Draping simulation of carbon/epoxy plain weave fabrics with non-orthogonal constitutive model and material behavior analysis of the cured structure

2018 ◽  
Vol 110 ◽  
pp. 172-182 ◽  
Author(s):  
Min-Gu Han ◽  
Seung-Hwan Chang
Keyword(s):  
Constitutive Model ◽  
Behavior Analysis ◽  
Material Behavior ◽  
Plain Weave ◽  
Draping Simulation

Prediction of Stress Relaxation in Power Plant Components Based on a Constitutive Model

2017 ◽  
Author(s):  
Y. Kostenko ◽  
K. Naumenko
Keyword(s):  
Power Plant ◽  
Stress Relaxation ◽  
Constitutive Model ◽  
Evolution Equations ◽  
Material Behavior ◽  
Assessment Procedure ◽  
Reliable Prediction ◽  
Inelastic Material ◽  
Plant Components

Many power plant components and joint connections are subjected to complex thermo-mechanical loading paths under severe temperature environments over a long period. An important part in the lifetime assessment is the reliable prediction of stress relaxation using improved creep modeling to avoid possible integrity or functionality issues and malfunction in such components. The aim of this work is to analyze the proposed constitutive model for advanced high chromium steels with the goal of predicting stress relaxation over the long term. The evolution equations of the constitutive model for inelastic material behavior are introduced to account for hardening and softening phenomena. The material properties were identified for 9–12%CrMoV steels in the creep range. The model is applied to the stress relaxation analysis of power plant components. The results for long-term assessment, which are encouragingly close to reality, will be presented and discussed. An outlook on further developments of the model and assessment procedure is also provided.

Experimental and Numerical Study of Soft Tissue Surrogate Behavior Under Ballistic Loading

2012 ◽  
Author(s):  
Ericka K. Amborn ◽  
Karim H. Muci-Küchler ◽  
Brandon J. Hinz
Keyword(s):  
Soft Tissue ◽  
Constitutive Model ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Study ◽  
Constitutive Models ◽  
Material Behavior ◽  
Good Representation

Studying the high strain rate behavior of soft tissues and soft tissue surrogates is of interest to improve the understanding of injury mechanisms during blast and impact events. Tests such as the split Hopkinson pressure bar have been successfully used to characterize material behavior at high strain rates under simple loading conditions. However, experiments involving more complex stress states are needed for the validation of constitutive models and numerical simulation techniques for fast transient events. In particular, for the case of ballistic injuries, controlled tests that can better reflect the effects induced by a penetrating projectile are of interest. This paper presents an experiment that tries to achieve that goal. The experimental setup involves a cylindrical test sample made of a translucent soft tissue surrogate that has a small pre-made cylindrical channel along its axis. A small caliber projectile is fired through the pre-made channel at representative speeds using an air rifle. High speed video is used in conjunction with specialized software to generate data for model validation. A Lagrangian Finite Element Method (FEM) model was prepared in ABAQUS/Explicit to simulate the experiments. Different hyperelastic constitutive models were explored to represent the behavior of the soft tissue surrogate and the required material properties were obtained from high strain rate test data reported in the open literature. The simulation results corresponding to each constitutive model considered were qualitatively compared against the experimental data for a single projectile speed. The constitutive model that provided the closest match was then used to perform an additional simulation at a different projectile velocity and quantitative comparisons between numerical and experimental results were made. The comparisons showed that the Marlow hyperelastic model available in ABAQUS/Explicit was able to produce a good representation of the soft tissue surrogate behavior observed experimentally at the two projectile speeds considered.

Bodner-Partom Constitutive Model and Nonlinear Finite Element Analysis

1990 ◽  
Vol 112 (3) ◽  
pp. 287-291 ◽  
Author(s):  
F. A. Kolkailah ◽  
A. J. McPhate
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Finite Element Model ◽  
Numerical Technique ◽  
Element Model ◽  
Material Behavior ◽  
Model Parameters ◽  
Elastic Plastic

In this paper, results from an elastic-plastic finite-element model incorporating the Bodner-Partom model of nonlinear time-dependent material behavior are presented. The parameters in the constitutive model are computed from a leastsquare fit to experimental data obtained from uniaxial stress-strain and creep tests at 650°C. The finite element model of a double-notched specimen is employed to determine the value of the elastic-plastic strain and is compared to experimental data. The constitutive model parameters evaluated in this paper are found to be in good agreement with those obtained by the other investigators. However, the parameters determined by the numerical technique tend to give response that agree with the data better than do graphically determined parameters previously used. The calculated elastic-plastic strain from the model agreed well with the experimental strain.

Progressive Damage Approach to Simulating Low Velocity Impact Response of Plain Weave C/SiC Composites

2010 ◽  
Vol 118-120 ◽  
pp. 241-245 ◽  
Author(s):  
Liu Ding Chen ◽  
Xiao Yan Tong ◽  
Xiang Zheng ◽  
Lei Jiang Yao
Keyword(s):  
Constitutive Model ◽  
Time History ◽  
Composite Plates ◽  
Experimental Results ◽  
Low Velocity Impact ◽  
Progressive Damage ◽  
Low Velocity ◽  
Velocity Impact ◽  
Plain Weave ◽  
User Subroutine

Based on progressive damage theory, a 3D laminated model with an orthotropic property in plane was established to simulate the response of plain weave carbon fiber reinforced silicon carbide(C/SiC) ceramic matrix composites(CMC) under low velocity impact(LVI). Intra-layer damage and inter-layer damage were taken into account, respectively. Three scalar damage variables, associated with the degradation of warp modulus, weft modulus and shear modulus, respectively, were proposed to characterize intra-layer damage evolutions. The intra-layer constitutive model was implemented into MSC.Dytran, via its user subroutine EXFAIL1. The potential delamination region was considered as a discrete cohesive zone. Three vector spring elements were placed into every two adjacent nodes to simulate the inter-layer joints. A scalar damage variables, associated with the degradation of the three vector spring elements, were brought forward to characterize the inter-layer damage evolutions. The inter-layer constitutive model was implemented into MSC.Dytran, via its user subroutine EXELAS. Damage area, indentation depth of C/SiC composite plates and time history of impact force were obtained to compare with experimental results. The numerical results show overall good agreement with experimental results.

A Second Generation of Numerical Implementation of Nonlinear Piezoelectric Models in Commercially Available Tools

2008 ◽  
Author(s):  
M. A. Siddiq Qidwai ◽  
V. G. DeGiorgi
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Domain Switching ◽  
Piezoelectric Materials ◽  
Nonlinear Behavior ◽  
Material Behavior ◽  
Device Performance ◽  
Performance Improvements ◽  
Rate Dependent ◽  
Theoretical Developments

Domain switching based nonlinear behavior is characteristic of relaxor-type piezoelectric material such as PMN-PT single crystals. These materials offer significant device performance improvements over traditional polycrystalline piezoelectric materials such as PZT-5A. The promise of increased performance of these materials has led to work in development of constitutive characterizations so that material behavior under load and material failure mechanisms can be understood and predicted. However, there is a gap between development of such theoretical developments and in workable manifestations available as part of commercial finite element codes for use in device design. In the current work, the authors extend previously documented implementation of a macro-mechanical constitutive model which addresses domain switching, into a commercially available finite element code. A rate dependent version of the constitutive model has been successfully realized and used to reproduce a variety of piezoelectric constitutive behaviors.

Computational Aspects in the Elasto/Viscoplastic Material Behavior of Solids

2012 ◽  
Vol 567 ◽  
pp. 192-199 ◽  
Author(s):  
Fabio de Angelis
Keyword(s):  
Constitutive Model ◽  
Material Behavior ◽  
Inelastic Behavior ◽  
Viscoplastic Material ◽  
Solid Materials ◽  
Numerical Examples ◽  
Computational Aspects ◽  
Computational Procedures ◽  
Consistent Tangent Operator ◽  
Algorithmic Procedure

In the present paper a computational algorithmic procedure is presented for modeling the elasto/viscoplastic behavior of solid materials. The effects of different loading programs on the inelastic behavior of rate-sensitive materials are analyzed with specific numerical examples. An appropriate solution scheme and a consistent tangent operator are applied which are capable to be adopted for general computational procedures. Numerical computations and results are reported which illustrate the rate-dependence of the constitutive model in use.

scholarly journals Effects of State Recovery on Creep Buckling Under Variable Loading

1990 ◽  
Vol 57 (2) ◽  
pp. 313-320 ◽  
Author(s):  
D. N. Robinson ◽  
S. M. Arnold
Keyword(s):  
Constitutive Model ◽  
Constitutive Relations ◽  
Thermal Recovery ◽  
Material Behavior ◽  
Creep Model ◽  
Rocket Engines ◽  
Variable Loading ◽  
State Recovery ◽  
Thermal Ratcheting ◽  
Creep Buckling

Structural alloys embody internal mechanisms that allow recovery of state with varying stress and elevated temperature; that is, they can return to a softer state following periods of hardening. Such material behavior is known to strongly influence structural response under some important thermomechanical loadings; for example, those involving thermal ratcheting. Here, we investigate the influence of dynamic and thermal recovery on the creep buckling of a column under variable loading. The column is taken as the idealized (Shanley) sandwich column. The constitutive model, unlike the commonly employed Norton creep model, incorporates a representation of both dynamic and thermal (state) recovery. The material parameters of the constitutive model are chosen to characterize NARloy-Z, a representative copper alloy used in thrust nozzle liners of reusable rocket engines. Variable loading histories include rapid cyclic unloading/reloading sequences and intermittent reductions of load for extended periods of time; these are superimposed on a constant load. The calculated results show that state recovery significantly affects creep buckling under variable loading. Failure to account for state recovery in the constitutive relations can lead to nonconservative predictions of the critical creep-buckling time.

scholarly journals Super-resolving material microstructure image via deep learning for microstructure characterization and mechanical behavior analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jaimyun Jung ◽  
Juwon Na ◽  
Hyung Keun Park ◽  
Jeong Min Park ◽  
Gyuwon Kim ◽  
...  
Keyword(s):  
Deep Learning ◽  
Behavior Analysis ◽  
Super Resolution ◽  
Local Stress ◽  
Mechanical Analysis ◽  
Microstructure Characterization ◽  
Material Behavior ◽  
Fe Model ◽  
Materials Research ◽  
Resolution Imaging

AbstractThe digitized format of microstructures, or digital microstructures, plays a crucial role in modern-day materials research. Unfortunately, the acquisition of digital microstructures through experimental means can be unsuccessful in delivering sufficient resolution that is necessary to capture all relevant geometric features of the microstructures. The resolution-sensitive microstructural features overlooked due to insufficient resolution may limit one’s ability to conduct a thorough microstructure characterization and material behavior analysis such as mechanical analysis based on numerical modeling. Here, a highly efficient super-resolution imaging based on deep learning is developed using a deep super-resolution residual network to super-resolved low-resolution (LR) microstructure data for microstructure characterization and finite element (FE) mechanical analysis. Microstructure characterization and FE model based mechanical analysis using the super-resolved microstructure data not only proved to be as accurate as those based on high-resolution (HR) data but also provided insights on local microstructural features such as grain boundary normal and local stress distribution, which can be only partially considered or entirely disregarded in LR data-based analysis.

scholarly journals Characterization of the Elastoplastic Response of Low Zn-Cu-Ti Alloy Sheets Using the CPB-06 Criterion

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3072
Author(s):  
Alister ◽  
Celentano ◽  
Signorelli ◽  
Bouchard ◽  
Pino ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Material Characterization ◽  
Yield Function ◽  
Alloy Sheet ◽  
Material Behavior ◽  
Bulge Test ◽  
Ti Alloy ◽  
Elastoplastic Behavior ◽  
Zinc Alloys ◽  
Hardening Law

Unlike other HCP metals such as titanium and magnesium, the behavior of zinc alloys has only been modeled in the literature. For the low Zn-Cu-Ti alloy sheet studied in this work, the anisotropy is clearly seen on the stress-strain curves and Lankford coefficients. These features impose a rigorous characterization and an adequate selection of the constitutive model to obtain an accurate representation of the material behavior in metal forming simulations. To describe the elastoplastic behavior of the alloy, this paper focuses on the material characterization through the application of the advanced Cazacu-Plunket-Barlat 2006 (CPB-06 for short) yield function combined with the well-known Hollomon hardening law. To this end, a two-stage methodology is proposed. Firstly, the material characterization is performed via tensile test measurements on sheet samples cut along the rolling, diagonal and transverse directions in order to fit the parameters involved in the associate CPB-06/Hollomon constitutive model. Secondly, these material parameters are assessed and validated in the simulation of the bulge test using different dies. The results obtained with the CPB-06/Hollomon model show a good agreement with the experimental data reported in the literature. Therefore, it is concluded that this model represents a consistent approach to estimate the behavior of Zn-Cu-Ti sheets under different forming conditions.

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