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After levelling, the strip had a residual stress distribution. The longbow after cutting is predicted too. Recommendation for practical use were proposed. Table Selection of software product and subroutine. Analysis performed in this study substantiates the need for high fidelity vehicle level progressive damage analyses PDA structural models for use in the verification and validation of proposed sub-scale structural models and to support required full-scale vehicle level testing.
PDA results are presented that capture and correlate the responses of sub-scale 3-stringer and 7-stringer panel models and an idealized 8-ft diameter fuselage model, which provides a vehicle level environment for the 7-stringer sub-scale panel model. Two unique skin-stringer attachment assumptions are considered and correlated in the models analyzed: the TIE constraint interface versus the cohesive element COH3D8 interface.
Evaluating different interfaces allows for assessing a range of predicted damage modes, including delamination and crack propagation responses.
The constitutive models of the user defined materials can be programmed in the user subroutine UMAT. Many user defined As originally proposed by Alonso, utilizing a critical state framework The data includes gap relative displacement and load measurements from three locations on the pad. Thirteen sets of data, from pads with different serial numbers, were provided. The thirty-nine gap-load curves were extracted from the thirteen supplied Excel spreadsheets and analyzed, and from those thirty-nine one set of data, representing a qualitative mean,more » was chosen to calibrate the model.
The data was converted from gap and load to nominal engineering strain and nominal stress in order to implement it in Abaqus. Strain computations required initial pad thickness estimates. In order to overcome the prematurity and the worse convergence of the Simple Genetic Algorithm SGA , a new strategy how to improve the efficiency of the SGA has been put forward.
In the new GA, the selection probability and the mutation probability are self-adaptive. Taking the stability of the composite laminates as the target, the optimized laminates sequences and radius of the hatch are analyzed with the help of ABAQUS. Compared with the SGA, the new GA method shows a good consistency, fast convergence and practical feasibility.
The biphasic cartilage model proposed by Mow et al. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made.
This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.
Modeling and simulation of Charpy impact test of maraging steel using Abaqus. This work emphasizes the modeling and simulation of Charpy impact test to evaluate fracture energy at different pendulum velocities of armor maraging steel using ABAQUS.
To evaluate the fracture energy, V-notch specimen is fractured using the Johnson and Cook Damage model. The Charpy impact tests are of great importance related to fracture properties of steels. Xie and Biggers 18 look at the effect width-to-hole-diameter ratio on open- hole The subroutine UMAT is used to define the. Wu developed a transformation scheme to model viscoelatic deformation due to glacial loading by commercial finite element package - ABAQUS. Benchmark tests confirmed that this method works extremely well on incompressible earth model.
Their study implies that Wu's method of stress transformation is inadequate to model the load induced deformation of a compressible earth under the framework of ABAQUS. In light of this, numerical experiments are carried out to find if there exist other methods that serve this purpose. All the tested methods are not satisfying as the results failed to converge through iterations, except at the elastic limit. Those tested methods will be outlined and the results will be presented.
Possible reasons of failure will also be discussed. A comparison between two solution techniques to solve the equations of glacially induced deformation of an elastic Earth. International journal for numerical methods in engineering, 75 4 , Wu, P.
Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress. Geophysical Journal International, 2 , The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties.
The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilever beam. Nonlinear static post-buckling and random response analyses are demonstrated for the first specimen. Static deflection shape control is demonstrated for the cantilever beam.
The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.
The model is implemented and supported within the core of the commercial codes, so no user subroutines or external calculations are necessary.
The model and resulting structural analysis has been previously demonstrated and experimentally verified for thermoelastic, vibration and acoustic, and structural shape control applications. The commercial implementations are described in related documents cited in the references, where various results are also shown that validate the commercial implementations relative to a research code. This paper is a companion to those documents in that it provides additional detail on the actual input files and solution procedures and serves as a repository for ASCII text versions of the input files necessary for duplication of the available results.
High-temperature, gas-cooled reactors HTGRs are usually helium-gas cooled, with a graphite core that can operate at reactor outlet temperatures much higher than can conventional light water reactors. In HTGRs, graphite components moderate and reflect neutrons. During reactor operation, high temperature and high irradiation cause damage to the graphite crystal and grains and create other defects.
This cumulative structural damage during the reactor lifetime leads to changes in graphite properties, which can alter the ability to support the designed loads.
The aim of the present research is to develop a finite-element code using commercially available ABAQUS software for the structural integritymore » analysis of graphite core components under extreme temperature and irradiation conditions. In addition, the Reactor Geometry Generator tool-kit, developed at Argonne National Laboratory, is used to generate finite-element mesh for complex geometries such as fuel bricks with multiple pin holes and coolant flow channels. This paper presents the proposed concept and discusses results of stress analysis simulations of a fuel block with H grade material properties.
Toward high-speed 3D nonlinear soft tissue deformation simulations using Abaqus software. We aim to achieve a fast and accurate three-dimensional 3D simulation of a porcine liver deformation under a surgical tool pressure using the commercial finite element software Abaqus.
The liver geometry is obtained using magnetic resonance imaging, and a nonlinear constitutive law is employed to capture large deformations of the tissue.
Effects of implicit versus explicit analysis schemes, element type, and mesh density on computation time are studied. We find that Abaqus explicit and implicit solvers are capable of simulating nonlinear soft tissue deformations accurately using first-order tetrahedral elements in a relatively short time by optimizing the element size. This study provides new insights and guidance on accurate and relatively fast nonlinear soft tissue simulations. Such simulations can provide force feedback during robotic surgery and allow visualization of tissue deformations for surgery planning and training of surgical residents.
A powerful multidimensional fuels performance capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. The various modeling capabilities are demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multi-pellet fuel rod, during both steady and transient operation.
Computational results demonstrate the importancemore » of a multidimensional fully-coupled thermomechanics treatment. Interestingly, many of the inherent deficiencies in existing fuel performance codes e.
Nanoscale Transport Optimization. This is accomplished by employing a user defined subroutine for fluid properties at the interface within the finite element Model Components: As noted above the governing equation for the material system is given as, Test process, milestones and inputs are unknowns to first-time users of the Advanced Materials Laboratory.
It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user , major milestones, facility capabilities, and inputs required by the facility.
Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide. In this study, Schaperys nonlinear viscoelastic constitutive model is implemented into the commercial finite element FE software ABAQUS via user defined subroutine user material , or UMAT to analyze asphalt pavement subjected to heavy truck loa Micromechanics and constitutive models for soft active materials with phase evolution.
Soft active materials , such as shape memory polymers, liquid crystal elastomers, soft tissues, gels etc. Micromechanics analysis of heterogeneous materials based on finite element method is a typically numerical way to study the thermal-mechanical behaviors of soft active materials with phase evolution.
While the constitutive models that can precisely describe the stress and strain fields of materials in the process of phase evolution can not be found in the databases of some commercial finite element analysis FEA tools such as ANSYS or Abaqus , even the specific constitutive behavior for each individual phase either the new formed one or the original one has already been well-known. So developing a computationally efficient and general three dimensional 3D thermal-mechanical constitutive model for soft active materials with phase evolution which can be implemented into FEA is eagerly demanded.
This paper first solved this problem theoretically by recording the deformation history of each individual phase in the phase evolution process, and adopted the idea of effectiveness by regarding all the new formed phase as an effective phase with an effective deformation to make this theory computationally efficient.
A user material subroutine UMAT code based on this theoretical constitutive model has been finished in this work which can be added into the material database in Abaqus or ANSYS and can be easily used for most soft active materials with phase evolution.
Model validation also has been done through comparison between micromechanical FEA and experiments on a particular composite material , shape memory elastomeric composite SMEC which consisted of an elastomeric matrix and the crystallizable fibre.
Results show that the micromechanics and the constitutive models developed in this paper for soft active materials with phase evolution are completely relied on. A powerful multidimensional fuels performance analysis capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. This new capability is demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multipellet fuel rod, during both steady and transient operation.
Comparisons are made between discrete andmore » smeared-pellet simulations. Computational results demonstrate the importance of a multidimensional, multipellet, fully-coupled thermomechanical approach. In this section Previously a user -defined material model for orthotropic bimodulus materials was developed for linear and nonlinear stress analysis of composite structures using either shell or solid finite elements within a nonlinear finite element analysis tool.
Extensions of this user -defined material model to thermo-mechanical progressive failure analysis are described, and the required input data are documented. The extensions include providing for temperature-dependent material properties, archival of the elastic strains, and a thermal strain calculation for materials exhibiting a stress-free temperature. The Materials and Nondestructive Evaluation Laboratory process, milestones and inputs are unknowns to first-time users. The potential audience for this guide includes both internal and commercial spaceflight hardware developers.
It is intended to assist their project engineering personnel in materials analysis planning and execution. Material covered includes a roadmap of the analysis process, roles and responsibilities of facility and user , major milestones, facility capabilities, and inputs required by the facility.
Samples of deliverables, products, and inputs necessary to define scope of analysis, cost, and schedule are included as an appendix to the guide. Comparisons of node-based and element-based approaches of assigning bone material properties onto subject-specific finite element models. Subject-specific finite element FE models can be generated from computed tomography CT datasets of a bone. A key step is assigning material properties automatically onto finite element models, which remains a great challenge.
This paper proposes a node-based assignment approach and also compares it with the element-based approach in the literature. The node-based approach assigns the material properties to each node of the finite element mesh, while the element-based approach assigns the material properties directly to each integration point of an element. Both approaches are independent from the type of elements. A number of FE meshes are tested and both give accurate solutions; comparatively the node-based approach involves less programming effort.
The node-based approach is also independent from the type of analyses; it has been tested on the nonlinear analysis of a Sawbone femur. The node-based approach substantially improves the level of automation of the assignment procedure of bone material properties.
It is the simplest and most powerful approach that is applicable to many types of analyses and elements. Published by Elsevier Ltd. Spectrally formulated user -defined element in conventional finite element environment for wave motion analysis in 2-D composite structures. Wave propagation analysis in 2-D composite structures is performed efficiently and accurately through the formulation of a User -Defined Element UEL based on the wavelet spectral finite element WSFE method.
The WSFE method is based on the first-order shear deformation theory which yields accurate results for wave motion at high frequencies. The 2-D WSFE model is highly efficient computationally and provides a direct relationship between system input and output in the frequency domain.
The UEL is formulated and implemented in Abaqus commercial finite element software for wave propagation analysis in 2-D composite structures with complexities. Five numerical examples are presented in this article, namely undamaged plate, impacted plate, plate with ply drop, folded plate and plate with stiffener.
Wave motions predicted by the developed UEL correlate very well with Abaqus simulations. Critical assessment of this model identified The model also takes into account the plastic expansion or contraction of voids and therefore the stresses are appropriately modified to account for. The scope of this white paper is Documentation of the 1-D user element subroutine is This is followed Characteristics of shear damage for 60SnPb solder material.
This paper presents an investigation of the development of a continuum damage model capable of accurately analyzing shear damage in 60SnPb solder material. Based on the theory of damage mechanics, an internal state variable known as the damage variable is introduced to characterize material degradation caused by the change of material microstructures under load. A damage surface in stress space is proposed to quantify damage initiation and its successive expanding surfaces to represent damage hardening.
With the aid of irreversible thermodynamics, the damage-coupled constitutive equations and the damage evolution equations are established. A failure criterion is proposed based on themore » accumulation of overall damage in the material.
The program is applied to predict shear deformation in a notched specimen. The predicted failure mode and maximum load agree well with those measured experimentally. The effect of finite element meshing on the numerical results is also examined and discussed. The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented.
First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. User applications driven by the community contribution framework MPContribs in the Materials Project. The MP is a searchable database of electronic structure properties of over 65, bulk solid materials , which is accessible through a web-based science-gateway.
We describe the motivation for enabling user contributions to the materials data and present the framework's features and challenges in the context of two real applications. These use cases illustrate how scientific collaborations can build applications with their own ' user -contributed' data using MPContribs.
The Nanoporous Materials Explorer application provides a unique searchmore » interface to a novel dataset of hundreds of thousands of materials , each with tables of user -contributed values related to material adsorption and density at varying temperature and pressure.
The Unified Theoretical and Experimental X-ray Spectroscopy application discusses a full workflow for the association, dissemination, and combined analyses of experimental data from the Advanced Light Source with MP's theoretical core data, using MPContribs tools for data formatting, management, and exploration.
The capabilities being developed for these collaborations are serving as the model for how new materials data can be incorporated into the MP website with minimal staff overhead while giving powerful tools for data search and display to the user community. The translation of these results is accomplished using a newly developed Python script. Full details of Our primary objective here is to report on these recent works conducted over the past decade, in the context of their incorporation into ABAQUS through the various user subroutines.
Representative results will be shown to demonstrate the features of the developed schemes. A numerical multi-scale model to predict macroscopic material anisotropy of multi-phase steels from crystal plasticity material definitions. A numerical multi-scale model is being developed to predict the anisotropic macroscopic material response of multi-phase steel. The embedded microstructure is given by a meso-scale Representative Volume Element RVE , which holds the most relevant features like phase distribution, grain orientation, morphology etc.
For the elasto-plastic response of the individual grains, single crystal plasticity based plastic potential functions are proposed as Abaqus material definitions. The plastic potential functions are derived using the Facet method for individual phases in the microstructure at the level of single grains. The proposed method is a new modeling framework and the results presented in terms of macroscopic flow curves are based on the building blocks of the approach, while the model would eventually facilitate the construction of an anisotropic yield locus of the underlying multi-phase microstructure derived from a crystal plasticity based framework.
Implicit and explicit solutions methods are used as appropriate. User subroutines Work is not Coupled material responses, such as electrical- thermal for capacitor materials or electrical. Waste minimization for commercial radioactive materials users generating low-level radioactive waste.
The objective of this document is to provide a resource for all states and compact regions interested in promoting the minimization of low-level radioactive waste LLW. This project was initiated by the Commonwealth of Massachusetts, and Massachusetts waste streams have been used as examples; however, the methods of analysis presented here are applicable to similar waste streams generated elsewhere. Massachusetts waste stream characterization data from key radioactive materials users in each category are used to illustrate the applicability of various minimization techniques.
The utility group is not included because extensive information specific to this category of LLW generators is available in the literature. Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. Abaqus is used at the global scale to model the overall composite structure.
A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.
This paper presents a viscoplasticity model taking into account the effects of change in grain or phase size and damage on the characterization of creep damage in 60SnPb solder. Based on the theory of damage mechanics, a two-scalar damage model is developed for isotropic materials by introducing the free energy equivalence principle.
The damage evolution equations are derived in terms of the damage energy release rates. In addition, a failure criterion is developed based on the postulation that a material element is said to have ruptured when the total damage accumulated in the element reaches a critical value. To illustrate the application of the model, several example cases are introduced to analyze, both numerically and experimentally, the tensile creep behaviors of the material at three stress levels.
The model is then applied to predict the deformation of a notched specimen under monotonic tension at room temperature 22 C. The results demonstrate that the proposed model can successfully predict the viscoplastic behavior of the solder material. To ensure desirable outcome of hydraulic fracturing based on ultra-short radius radial systems, it is required to investigate the stress distribution regularity and stability of the cement sheath. On the basis of the theoretical model of the cement sheath stress distribution, a reservoir mechanical model was built using the finite element software, ABAQUS , according to the physical property of a certain oil reservoir of the Shengli oilfield.
The stress distribution of the casing-cement-sheath-formation system under the practical condition was simulated, based on which analyses were conducted from multiple points of view. Results show that the stress on the internal interface of the cement sheath exceeds that on the external interface, and fluctuates with higher amplitudes, which means that the internal interface is the most failure-prone.
The unevenness of the cement sheath stress distribution grows with the increasing horizontal principal stress ratio, and so does the variation magnitude. This indicates that higher horizontal principal stress ratios are unfavourable for the structural stability of the cement sheath.
Both the wellbore quantity of the URRS and the physical property of the material can affect the cement sheath distribution. At last, the impact level of the above factor was analysed, with the help of the grey correlation analysis.
An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions.
Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. For textile materials , comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension.
Computer codes were developed to perform the analysis. User Test Planning Guide. Revision 1. This report describes User Education Resources USER , an Australian database containing both print and audiovisual materials related to library instruction.
Intended to make a wide range of ideas readily available to librarians interested in educating library patrons, USER collects catalog guides, classification guides, evaluation forms, floor…. Identifies and describes sublevels of novices using a database management package, clustering those whose interaction is effective, partially effective, and totally ineffective. Among assistance documentation, functional tree diagrams FTDs were more beneficial to partially effective users than traditional reference material.
The results have…. Long-term injection and storage of CO2 in deep underground reservoirs may significantly modify the geomechanical behavior of rocks since CO2 can react with the constituent phases of reservoir rocks and modify their composition.
This can lead to modifications of their geomechanical properties i. This paper attempts to elucidate the geochemical effects of CO2 on geomechanical properties of typical reservoir rocks by means of numerical analyses using the STOMP- ABAQUS sequentially coupled simulator that includes the capability to handle geomechanics and the reactive transport of CO2 together with a module EMTA to compute the homogenized rock poroelastic properties as a function of composition changes.
The ABAQUS models then read STOMP output data for cell center coordinates, gas pressures, aqueous pressures, temperatures, saturations, constituent volume fractions, as well as permeability and porosity that are affected by chemical reactions. Explicit and implicit springback simulation in sheet metal forming using fully coupled ductile damage and distortional hardening model. The springback is an important phenomenon which accompanies the forming of metallic sheets especially for high strength materials.
A quantitative prediction of springback becomes very important for newly developed material with high mechanical characteristics. In this work, a numerical methodology is developed to quantify this undesirable phenomenon. The most important ingredient of this methodology consists on the use of highly predictive mechanical model. A thermodynamically-consistent, non-associative and fully anisotropic elastoplastic constitutive model strongly coupled with isotropic ductile damage and accounting for distortional hardening is then used.
An algorithm for local integration of the complete set of the constitutive equations is developed. This algorithm considers the rotated frame formulation RFF to ensure the incremental objectivity of the model in the framework of finite strains. Finally, the purpose of this work is to evaluate the reliability of different methods predict efficiently springback in sheet metal forming. The model is implemented using Abaqus user element subroutine and verified against the experimental ABAQUS and other commercially available finite element codes do not have the capability to solve general electromigration problem directly.
Hazardous Materials Control Module. Author s 8. Performing Organization After presenting. Formability of steel and aluminium alloys in hot stamping and cold die quenching processes is studied in this research. Viscoplastic-damage constitutive equations are developed and determined from experimental data for the prediction of viscoplastic flow and ductility of the materials. An FE process simulation model and numerical procedures are established for the modeling of hot stamping processes for a spherical part with a central hole.
Different failure modes failure takes place either near the central hole or in the mid span of the part are obtained. To validate the simulation results, a test programme is developed, a test die set has been designed and manufactured, and tests have been carried out for the materials with different forming rates.
It has been found that very close agreements between experimental and numerical process simulation results are obtained for the ranges of temperatures and forming rates carried out. Federal Register , , , , For Applied Materials China , Inc Acceptable noise level ANL with Danish and non-semantic speech materials in adult hearing-aid users. The acceptable noise level ANL test is used for quantification of the amount of background noise subjects accept when listening to speech.
ANL was measured in three conditions in both ears at two test sessions. ANLs were similar to results with American English speech material. The coefficient of repeatability CR was 6. The magnitude of the CR indicates that ANL with Danish and non-semantic speech materials is not suitable for prediction of individual patterns of future hearing-aid use or evaluation of individual benefit from hearing-aid features. The SME provides an integrated set of management tools that can be used by software development managers in their day-to-day management and planning activities.
This document provides an overview of the SME, a description of all functions, and detailed instructions concerning the software's installation and use. A multi- user real time inventorying system for radioactive materials : a networking approach.
A computerized system for radioisotope management and real time inventory coordinated across a large organization is reported. It handles hundreds of individual users and their separate inventory records. Use of highly efficient computer network and database technologies makes it possible to accept, maintain, and furnish all records related to receipt, usage, and disposal of the radioactive materials for the users separately and collectively.
Radioisotope decay is automatically calculated by the program, so that it can make the up-to-date radioisotope inventory data of an entire institution available immediately. The system is specifically designed to allow use by large numbers of users about and accommodates high volumes of data input and retrieval without compromising simplicity and accuracy. Overall, it is an example of a true multi- user , on-line, relational database information system that makes the functioning of a radiation safety department efficient.
SPECabq v. The SPEC model was published in the open literature in The subroutine is used to analyze the thermomechanical behavior of isotropic polymers predicting things like how a polymer may undergo stress or volume relaxation under different temperature and loading environments.
This subroutine enables the ABAQUSmore » finite element code to be used for analyzing the thermo-mechanical behavior of samples and parts that are made from glassy polymers. The entire model 22 including the boundary. The new model was used to simulate the thermally reversible flow behaviour for C-S type two-step deformation, and the results are A tangent modulus method [48] was used for the time This approach was motivated by modern understanding of dislocation mechanisms for Ni3Al.
Owing to the attendant large strains and This finding is consistent with the In accordance with the previously observed larger thermal - expansion effects in Al, Figure 5 b shows that the. Zhang, K. Simulation of microplasticity -induced deformation in uniaxially strained ceramics by 3-D Voronoi. Thermal analysis of friction riveting of dissimilar materials. Friction riveting is a new technique which finds its applications in a variety of domains, where there is a need to join dissimilar materials for the sake of achieving weight reduction of the components produced especially in the fields of aerospace and automobile.
In this present work, a numerical simulation on the heat transfer analysis has been done to predict the variation of temperature on the surface of the components being joined. Owing to the applications, Aluminum rivet is chosen for friction riveting on Poly Methyl Metha Acrylate base material.
Abaqus explicit version 6. Heat flux at the joint interface has been computed and thermal distribution at the work material is predicted. Nemeth, Noel N. A finite element FE model is developed for the progressive failure analysis of fiber reinforced polymer laminates. The gradual degradation of the material properties is controlled by the individual fracture energies of fiber and matrix.
The failure and damage in composite laminates containing a central hole subjected to uniaxial tension are simulated. The numerical results show that the damage model can be used to accurately predicte the progressive failure behaviour both qualitatively and quantitatively.
Users ' input has been utilized to help: 1 design the…. Material modeling of biofilm mechanical properties. A biofilm material model and a procedure for numerical integration are developed in this article.
They enable calculation of a composite Young's modulus that varies in the biofilm and evolves with deformation. Compressive, tensile, and shear loads are imposed, and the way the biofilm mechanical properties evolve is assessed. Results show that the local values of Young's modulus increase under compressive loading, since compression results in the voids "closing," thus making the material stiffer.
For the opposite reason, biofilm stiffness decreases when tensile loads are imposed. Furthermore, the biofilm is more compliant in shear than in compression or tension due to the how the elastic shear modulus relates to Young's modulus.
M50 steel V-Ring raceways, and extended the bearing life prediction methods of Ioannides and Harris 10 to predict the remaining useful life of Second Edition, , Cambridge University Finite Element Model Geometry Figure 6. Tracings of spall edges from M50 and Pyrowear bearing steels. Author s S. Performing Organization Rapt. Dress ESA WANG 1I. While many surveys aim primarily at measuring general user satisfaction, this survey is dedicated to understanding music users ' needs, usage patterns, and preferences towards various collections.
Findings showed dissimilar use behavior and perceived importance of materials between academic- and performance-oriented music users. Needs for different…. After a The majority of creep tests are uniaxial compressive tests Kennedy, and Perry Volume 1: Main Text.
The heat transfer capability of ABAQUS uses the finite element method to numerically solve the governing differential The different concrete mixture. Proceedings of the U. Circumferential, or cross-barrel The code will perform static, dynamic, and thermal anal- ysis on a broad range of structures In this investigation, a thermo-mechanical model of pebble beds is adopted and developed based on experiments by Dr. The framework of the present material model is composed of a non-linear elastic law, the Drucker-Prager-Cap theory, and a modified creep law.
Furthermore, the volumetric inelastic strain dependent thermal conductivity of beryllium pebble beds is taken into account and full thermo-mechanical coupling is considered. Investigation showed that the Drucker-Prager-Cap model implemented in ABAQUS can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importancemore » with respect to the application of pebble beds in fusion blankets.
An elastic predictor radial return mapping algorithm is used to solve the non-associated plasticity iteratively, and a proper tangent stiffness matrix is obtained for cost-efficiency in the calculation.
An explicit creep mechanism is adopted for the prediction of time-dependent behaviour in order to represent large creep strains in high temperature. The oedometric compression tests and creep tests of pebble beds at different temperatures are simulated with the help of the present UMAT and UMATHT routines, and the comparison between the simulation and the experiments is made.
It is challenging for primary care physicians PCPs to review and apply the growing amount of clinical evidence available. Printed educational materials PEMs , which synthesize evidence, are often ineffective at improving knowledge, possibly due to poor design and limited uptake.
In this study, we collected PCP preferences for the design and content of physician-oriented PEMs and determined key attributes that may increase their usability and uptake. Focus groups included discussion about whether and how participants use PEMs, feedback on three examples of PEMs, and a discussion on general format and design preferences in PEMs. We analyzed focus group transcripts using a thematic analysis and summarized results in a list of user preferences.
Four focus groups were held with 13 PCPs. We found that participants only read PEMs relevant to their patients and prefer short, concise documents, with links to sources that can provide more detailed information. Simplicity of materials was important, with many participants preferring PEMs without lengthy backgrounds or scientific explanations. Most participants wanted to see key messages highlighted to easily assess the relevance of the materials to their practice. Some participants shared physician-oriented PEMs with patients.
This study shows that PCPs may prefer shorter, simpler, and more concise documents that have less scientific detail but provide references to further information sources. It is important to understand end user preferences for the design and content of these materials to enhance their uptake. Splitting, ultimate failure load and the damage path in center notched composite specimens subjected to in-plane tension loading are predicted using progressive failure analysis methodology.
A 2-D Hashin-Rotem failure criterion is used in determining intra-laminar fiber and matrix failures. A 2-D finite element model is used for predicting the intra-laminar damages. The importance of modeling delamination in progressive failure analysis methodology is recognized for future studies.
The use of an explicit integration dynamics code for simple specimen geometry and static loading establishes a foundation for future analyses where complex loading and nonlinear dynamic interactions of damage and structure will necessitate it.
As a result, a Langragian treatment of the structure is preferred. Therefore, a finite element solver with the capability of This is followed by a remapping The hydrostatic behavior of. Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam.
Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS , finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element.
Numerical analysis of strain localization for transversely isotropic model with non-coaxial flow rule. To analyse the strain localization behavior of geomaterials, the forward Euler schemes and the tangent modulus matrix are formulated based on the transversely isotropic yield criterion with non-coaxial flow rule developed by Lade, the program code is implemented based on the user subroutine UMAT of ABAQUS.
The influence of the material principal direction on the strain localization and the bearing capacity of the structure are investigated and analyzed. Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of geostructures.
A hybrid modeling system designed to support decision making in the optimization of extrusion of inhomogeneous materials. Mathematical models and a hybrid modeling system are developed for the implementation of the experimental-calculation method for the engineering analysis and optimization of the plastic deformation of inhomogeneous materials with the purpose of improving metal-forming processes and machines.
Practical application of the software solution is exemplified by modeling the process of extrusion of a bimetallic billet. The results of the engineering analysis and optimization of the extrusion process are shown, the material damage being monitored. Mechatronic Materials and Systems. One side of the structure is fully clamped, while the other is free to displace. As in prior assessments [ To simulate the complete system, the core and the Kagome face members are modeled using linear To simulate the complete actuation system, the core and Kagome members are modeled using linear Timoshenko-type beams, while the solid.
Wheelchair propulsion exposes the user to a high risk of shoulder injury and to whole-body vibration that exceeds recommendations of ISO Reducing the mechanical work required to travel a given distance WN-WPM, weight-normalized work-per-meter can help reduce the risk of shoulder injury, while reducing the vibration transmissibility VT of the wheelchair frame can reduce whole-body vibration.
New materials such as titanium and carbon are used in today's wheelchairs and are advertised to improve both parameters, but current knowledge on this matter is limited. In this study, WN-WPM and VT were measured simultaneously and compared between six folding wheelchairs 1 titanium, 1 carbon, and 4 aluminium.
Ten able-bodied users propelled the six wheelchairs on three ground surfaces. The subjects discussed include the following: 1 statics and buckling, 2 vibrations and dynamics, 3 substructing, 4 new capability, 5 user 's experience, and 6 system experience. A simple continuum damage mechanics CDM based 3D progressive damage analysis PDA tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code.
This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions.
Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads. Cyclic softening based on dislocation annihilation at sub-cell boundary for SA Grade-6 C-Mn steel. In this work, the response of SA Grade-6 C-Mn steel subjected to uniaxial and in-phase biaxial tension-torsion cyclic loading is experimented and an attempt is made to model the material behaviour.
The relevant material parameters are extracted from the appropriate experimental results and metallurgical investigations. The material model is plugged as user material subroutine into ABAQUS FE platform to simulate pre-saturation low cycle fatigue loops with cyclic softening and other cyclic plastic behaviour under prescribed loading.
The stress-strain hysteresis loops and peak stress with cycles were compared with the experimental results and good agreements between experimental and simulated results validated the material model. Turon s methodology for determining optimal analysis parameters for the simulation of progressive delamination is reviewed. The Abaqus cohesive element, COH3D8, and a user -defined cohesive element are used to develop finite element models of the double cantilever beam specimen, the end-notched flexure specimen, and the mixed-mode bending specimen to simulate progressive delamination growth in Mode I, Mode II, and mixed-mode fracture, respectively.
The predicted responses are compared with their analytical solutions. The results show that for single-mode fracture, the predicted responses obtained with the Abaqus cohesive element correlate well with the analytical solutions.
For mixed-mode fracture, it was found that the response predicted using COH3D8 elements depends on the damage evolution criterion that is used. The energy-based criterion overpredicts the peak loads and load-deflection response. The results predicted using a tabulated form of the BK criterion correlate well with the analytical solution and with the results predicted with the user -written element.
A 3D moisture-stress FEM analysis for time dependent problems in timber structures. This paper presents a 3D moisture-stress numerical analysis for timber structures under variable humidity and load conditions. An orthotropic viscoelastic-mechanosorptive material model is specialized on the basis of previous models. Both the constitutive model and the equations needed to describe the moisture flow across the structure are implemented into user subroutines of the Abaqus finite element code and a coupled moisture-stress analysis is performed for several types of mechanical loads and moisture changes.
The presented computational approach is validated by analyzing some wood tests described in the literature and comparing the computational results with the reported experimental data.
Fracture simulation of restored teeth using a continuum damage mechanics failure model. The aim of this paper is to validate the use of a finite-element FE based continuum damage mechanics CDM failure model to simulate the debonding and fracture of restored teeth. Fracture testing of plastic model teeth, with or without a standard Class-II MOD mesial-occusal-distal restoration, was carried out to investigate their fracture behavior.
The material parameters needed for the CDM model to simulate fracture are obtained through separate mechanical tests. The predicted results are then compared with the experimental data of the fracture tests to validate the failure model. To learn more, view our Privacy Policy.
To browse Academia. Faisal Khan. The multi-accident catastrophe which occurred in a refinery at Vishakhapatnam, India, on September 14, , claiming 60 lives and causing damages to property worth over Rs million, is the most recent example of the damage potential of domino effect.
But, even as the domino effect has been documented since , very little attention has been paid towards modeling this phenomena. In this paper we have provided a conceptual framework based on sets of appropriate models to forecast domino effects, and assess their likely magnitudes and adverse impacts, while conducting risk assessment in a chemical process industry.
The utilizability of the framework has been illustrated with a case study. Maria Laura Mastellone. S-z Aq. Aijaz Khoso. Log in with Facebook Log in with Google.
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