Simulation of Post Failure Response in Fiber Composites

2011 ◽  
Author(s):  
Badrinath Veluri ◽  
Henrik Myhre Jensen
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Constitutive Model ◽  
Failure Mechanism ◽  
Inclination Angle ◽  
Layered Materials ◽  
Fiber Composites ◽  
Finite Element Code ◽  
Compressive Failure ◽  
Localization Of Deformation

This study focuses on the compressive failure mechanism in the form of kinkband formation in fiber composites. Taking into account the non-linearities of the constituents, a constitutive model for unidirectional layered materials has been developed and incorporated as a user material in a commercially available finite element code to study effects of kinkband inclination angle and micro-geometry on kinkband formation. The localization of deformation into a single kinkband is studied. In the post failure regime a state is reached where deformation in the kinkband gets stabilized and the kinkband broadens under steady-state conditions.

Constitutive Model of Solid Propellant with Mechanical Damage and Aging

2012 ◽  
Vol 198-199 ◽  
pp. 197-201 ◽  
Author(s):  
Xiao Jun Zhang ◽  
Xin Long Chang ◽  
Shi Ying Zhang ◽  
Shun Xiang Chen ◽  
Jie Tang Zhu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Constitutive Equations ◽  
Solid Propellant ◽  
Damage Mechanics ◽  
Engineering Application ◽  
Mechanical Damage ◽  
Finite Element Code ◽  
Nonlinear Characteristics

Mechanical damage and aging are the main mechanisms of nonlinear characteristics of solid propellant.A comprehensive big strain visco-elastic constitutive model with damage mechanics and aging was established, by using the visco-elastic constitutive equations form expressed by the generalized variable, introducing damage variables, and taking the relaxation modules after aging to characterize the aging. The correctness of the model was verified through experiments. the parameters need by modeling are easy to be got, and converted into the finite element code to do the simulation computation, then the model is suitable for the engineering application.

Constitutive Modeling for Impact Simulation of Random Fiber Composite Structures

1999 ◽  
Author(s):  
Haeng-Ki Lee ◽  
Srdan Simunovic
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Structures ◽  
Fiber Composite ◽  
Damage Model ◽  
Yield Function ◽  
Progressive Damage ◽  
Finite Element Code ◽  
Effective Yield ◽  
Damage Constitutive Model

Abstract A constitutive model for progressive crushing is presented to predict impact behavior and damage evolution in random carbon fiber polymer matrix composites (RCFPMCs). Based on the ensemble-volume averaging process and first-order effects of eigenstrains due to the existence of prolate fibers, an effective yield criterion is derived to estimate the overall elastoplastic damage responses. First, an effective elastoplastic constitutive damage model for aligned fiber-reinforced composites is proposed. A micromechanical damage constitutive model for RCFPMCs is then developed. The governing field equations and overall yield function for aligned fiber-orientations are averaged over all orientations to obtain the constitutive relations and effective yield function of RCFPMCs. Finally, the complete progressive damage constitutive model is implemented into finite element code DYNA3D to solve large scale problems such as automobile components and systems. An advantage of the progressive damage analysis is that the information from the progressive damage model can be implemented into finite element code as material input properties and thus the calculations required in the constitutive model can be greatly reduced.

Research on WALKER Constitutive Model Tangent Modulus

2012 ◽  
Vol 249-250 ◽  
pp. 113-117
Author(s):  
Yan Chen ◽  
Qing Wu Wang ◽  
Quan Shan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Constitutive Model ◽  
Constitutive Equations ◽  
Tangent Modulus ◽  
Finite Element Code ◽  
Numerical Examples ◽  
Rate Dependent ◽  
Backward Euler ◽  
Elasto Plasticity

In elasto-plasticity computation on materials by sub-increase finite element method, in general, it is necessary to calculate the consistent tangent modulus of elements. In this paper, based on the backward Euler integration, for an unified viscoplasticity constitutive equations, a new expression of consistent tangent modulus is derived for rate-dependent plasticity. The constitutive equations and consistent tangent modulus expression are implemented into a commercial finite element code-MARC. Numerical examples are given to verify the finite element implementation.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Steady-State Kink Band Propagation in Layered Materials

2018 ◽  
Vol 85 (6) ◽  
Author(s):  
Simon P. H. Skovsgaard ◽  
Henrik Myhre Jensen
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Finite Element Model ◽  
Analytical Model ◽  
Element Model ◽  
Kink Band ◽  
Layered Materials ◽  
Transcendental Equation ◽  
Experimental Findings ◽  
Good Agreement

Failure by steady-state kink band propagation in layered materials is analyzed using three substantially different models. A finite element model and an analytical model are developed and used together with a previously introduced constitutive model. A novel methodology for simulating an infinite kink band is used for the finite element model using periodic boundary conditions on a skewed mesh. The developed analytical model results in a transcendental equation for the steady-state kink band propagation state. The three models are mutually in good agreement and results obtained using the models correlate well with the previous experimental findings.

Dynamic out-of-plane compressive failure mechanism of C/C composite: Strain rate effect on the defect propagation and microstructure failure

2021 ◽  
pp. 1-31
Author(s):  
Fei Guo ◽  
Qingguo Fei ◽  
Yanbin Li ◽  
Nikhil Gupta
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Maximum Stress ◽  
Testing Machine ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Compressive Failure ◽  
Macro Scale ◽  
Out Of Plane

Abstract Out-of-plane compression experiments with the strain rate from 0.0001/s to 1000/s are performed on 3D fine weave pierced Carbon/Carbon (C/C) composite using a universal testing machine, a high-speed testing machine, and a split Hopkinson pressure bar (SHPB). The compressive failure mechanism of the composite is analyzed by multi-scale analysis method, which ranges from micro-scale defect propagation, through meso-scale microstructure failure, to macro-scale material failure. In order to predict the out-of-plane compressive properties of 3D fine weave pierced C/C composite at different strain rates, a strain-rate-dependent compressive constitutive model is proposed. The results show that the out-of-plane compressive behavior of the 3D fine weave pierced C/C composite is sensitive to strain rate. With increasing the strain rate, the initial compressive modulus, the maximum stress and the strain at the maximum stress increase. The difference in mechanical behavior between quasi-static and high strain rate compression is owing to the strain rate effect on the defect propagation of the 3D fine weave pierced C/C composite. The proposed constitutive model matches well with the experimental data.

A Crystallographic Model for Nickel Base Single Crystal Alloys

1988 ◽  
Vol 55 (2) ◽  
pp. 325-331 ◽  
Author(s):  
L. T. Dame ◽  
D. C. Stouffer
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Single Crystal ◽  
Three Dimensional ◽  
Rate Sensitivity ◽  
Mechanical Analysis ◽  
Orientation Dependence ◽  
Finite Element Code ◽  
Nickel Base ◽  
Octahedral Slip

The purpose of this research is to develop a tool for the mechanical analysis of nickel-base single-crystal superalloys, specifically Rene N4, used in gas turbine engine components. This objective is achieved by developing a rate-dependent anisotropic constitutive model and implementing it in a nonlinear three-dimensional finite-element code. The constitutive model is developed from metallurgical concepts utilizing a crystallographic approach. An extension of Schmid’s law is combined with the Bodner-Partom equations to model the inelastic tension/compression asymmetry and orientation-dependence in octahedral slip. Schmid’s law is used to approximate the inelastic response of the material in cube slip. The constitutive equations model the tensile behavior, creep response and strain-rate sensitivity of the single-crystal superalloys. Methods for deriving the material constants from standard tests are also discussed. The model is implemented in a finite-element code, and the computed and experimental results are compared for several orientations and loading conditions.

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