Micromechanical analysis of UD CFRP composite lamina under multiaxial loading with different loading paths

2021 ◽  
pp. 114024
Author(s):  
Jiayun Chen ◽  
Lei Wan ◽  
Yaser Ismail ◽  
Pengfei Hou ◽  
Jianqiao Ye ◽  
...  
Keyword(s):  
Multiaxial Loading ◽  
Micromechanical Analysis ◽  
Loading Paths ◽  
Cfrp Composite

scholarly journals Development of a kinematic hardening rule to assess ratcheting response of materials under various multiaxial loading spectra

2021 ◽  
Author(s):  
SeyedMahdi Hamidinejad
Keyword(s):  
Experimental Data ◽  
Dynamic Recovery ◽  
Kinematic Hardening ◽  
Multiaxial Loading ◽  
Steel Alloys ◽  
Modified Model ◽  
Hardening Rule ◽  
Loading Paths ◽  
Ratcheting Strain ◽  
Stress Cycles

The present thesis develops an Armstrong-Frederick (A-F) type coupled kinematic hardening rule to assess ratcheting response of steel alloys under various multiaxial loading paths. The hardening rule is constructed on the basis of the recently proposed Ahmadzadeh-Varvani (AV) hardening rule to further evaluate the ratcheting response of materials under multiaxial loading spectra. The modified model offers a simple framework with limited number of terms and coefficients in the dynamic recovery portion of the model. The dynamic recovery further holds inner product of plastic strain increment p dand backstress unit vector a a with different directions under multiaxial stress cycles enables the model to track different directions. Term 1/ 2 n. a a taking positive values less than unity for multiaxial loading conditions is to control the accumulation rate of ratcheting strain and to prevent the modified model to experience plastic shakedown over stress cycles in stage II. Term(2 n. a a ) taking the values between 1 and 3 under multiaxial loading, magnifies the effect of coefficient γ2 to take into account the nonproportionality effect of various loading paths and further to shift down the predicted ratcheting strain over the stress cycles. The predicted ratcheting curves by the modified rule were compared with those predicted based on earlier developed hardening rules of Ohno-Wang (O-W), Jiang-Sehitoglu (J-S), McDowell, and Chen-Jiao-Kim (C-J-K) holding relatively complex framework and more number of coefficients. The O-W, the J-S, McDowell and C-J-K models mainly deviated from the experimental ratcheting strain of steel alloys for various multiaxial loading histories, while the predicted curves of the modified model closely agreed with experimental data of steel samples over ratcheting stages. The predicted ratcheting curves based on the modified model closely agreed with experimental data of steel samples under various multiaxial step-loading histories. The modified model was also found capable of predicting ratcheting in the opposite direction as the tensile axial mean stress dropped in magnitude. The O-W, J-S, McDowell and C-J-K models holding more backstress components and coefficients require longer Central Processing Unit (CPU) time. While time required for ratcheting assessment using the modified hardening rule was found to be twice shorter due to its simpler framework and limited number of coefficients.

Experimental validation of shape memory material model implemented in commercial finite element software under multiaxial loading

2018 ◽  
Vol 29 (14) ◽  
pp. 2954-2965 ◽  
Author(s):  
Hamid Khodaei ◽  
Patrick Terriault
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Material Model ◽  
Multiaxial Loading ◽  
Finite Element Software ◽  
Loading Paths ◽  
Dependent Behavior ◽  
Path Dependent

Shape memory alloys are used in ever-increasing numbers of applications, such as implants made of porous shape memory alloys, where the material is subjected to complex loading conditions with various loading paths. Finite element simulation of such parts requires utilizing a constitutive model that is able to capture the multiaxial and path-dependent behavior of shape memory alloys. The main objective of this article is to investigate the accuracy of the constitutive model implemented in current commercial finite element software such as Ansys in predicting the shape memory alloys mechanical response under different multiaxial loading paths. To this end, several isothermal tests were conducted on thin-walled NiTi tubes with uniaxial, as well as multiaxial, path-varying loadings. The performance of the material model within Ansys was then investigated by finite element modeling of the sample tubes and performing simulations of the tests. Comparing the finite element results with experimental data, it was observed that while this model provided a close prediction of the uniaxial tensile superelastic response, it was not able to reproduce the multiaxial and path-dependent behavior of the shape memory alloy samples with sufficient accuracy. A brief discussion of the reasons behind the inaccuracy of the current model and potentially promising models for future investigation are provided.

New approach for analysis of complex multiaxial loading paths

2014 ◽  
Vol 62 ◽  
pp. 21-33 ◽  
Author(s):  
V. Anes ◽  
L. Reis ◽  
B. Li ◽  
M. Fonte ◽  
M. de Freitas
Keyword(s):  
Multiaxial Loading ◽  
New Approach ◽  
Loading Paths

scholarly journals Development of a kinematic hardening rule to assess ratcheting response of materials under various multiaxial loading spectra

2021 ◽  
Author(s):  
SeyedMahdi Hamidinejad
Keyword(s):  
Experimental Data ◽  
Dynamic Recovery ◽  
Kinematic Hardening ◽  
Multiaxial Loading ◽  
Steel Alloys ◽  
Modified Model ◽  
Hardening Rule ◽  
Loading Paths ◽  
Ratcheting Strain ◽  
Stress Cycles

The present thesis develops an Armstrong-Frederick (A-F) type coupled kinematic hardening rule to assess ratcheting response of steel alloys under various multiaxial loading paths. The hardening rule is constructed on the basis of the recently proposed Ahmadzadeh-Varvani (AV) hardening rule to further evaluate the ratcheting response of materials under multiaxial loading spectra. The modified model offers a simple framework with limited number of terms and coefficients in the dynamic recovery portion of the model. The dynamic recovery further holds inner product of plastic strain increment p dand backstress unit vector a a with different directions under multiaxial stress cycles enables the model to track different directions. Term 1/ 2 n. a a taking positive values less than unity for multiaxial loading conditions is to control the accumulation rate of ratcheting strain and to prevent the modified model to experience plastic shakedown over stress cycles in stage II. Term(2 n. a a ) taking the values between 1 and 3 under multiaxial loading, magnifies the effect of coefficient γ2 to take into account the nonproportionality effect of various loading paths and further to shift down the predicted ratcheting strain over the stress cycles. The predicted ratcheting curves by the modified rule were compared with those predicted based on earlier developed hardening rules of Ohno-Wang (O-W), Jiang-Sehitoglu (J-S), McDowell, and Chen-Jiao-Kim (C-J-K) holding relatively complex framework and more number of coefficients. The O-W, the J-S, McDowell and C-J-K models mainly deviated from the experimental ratcheting strain of steel alloys for various multiaxial loading histories, while the predicted curves of the modified model closely agreed with experimental data of steel samples over ratcheting stages. The predicted ratcheting curves based on the modified model closely agreed with experimental data of steel samples under various multiaxial step-loading histories. The modified model was also found capable of predicting ratcheting in the opposite direction as the tensile axial mean stress dropped in magnitude. The O-W, J-S, McDowell and C-J-K models holding more backstress components and coefficients require longer Central Processing Unit (CPU) time. While time required for ratcheting assessment using the modified hardening rule was found to be twice shorter due to its simpler framework and limited number of coefficients.

Comparative Study of the Additional Hardening Effects of Three Structural Steels

2006 ◽  
Vol 514-516 ◽  
pp. 534-538
Author(s):  
Luís G. Reis ◽  
Bin Li ◽  
Manuel de Freitas
Keyword(s):  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Great Influence ◽  
Structural Steels ◽  
Loading Path ◽  
Multiaxial Loading ◽  
Cycle Fatigue ◽  
Proportional Loading ◽  
Loading Paths ◽  
Additional Hardening

For a safe and reliable design of components, it is needed to study the effects of multiaxial loading and particularly the non-proportional loadings on the fatigue damage. The objective of this paper is to evaluate and compare the additional hardening effects of proportional and non-proportional loading paths. Low-cycle fatigue behaviour of three structural steels: CK45 (ferritic-perlitic microstructure) normalized steel, 42CrMo4 (bainitic microstructure) quenched and tempered steel and stainless steel (austenitic microstructure) X10CrNiS 18 9 are studied under different proportional and non-proportional loading paths and different levels. A series of tests of biaxial low-cycle fatigue composed of tension/compression with static or cyclic torsion were carried out on a biaxial servo-hydraulic testing machine Instron 8088. The experiments showed that the three materials studied have very different additional hardening behaviour, under multiaxial cyclic loading paths. The local cyclic stress/strain states are influenced by the multiaxial loading paths due to interactions between the normal stress and shear stress during cyclic plastic deformation. The microstructure is an important key and has a great influence on the additional hardening. The additional hardening effect is dependent of the loading path and also the intensity of the loading.

High Fidelity Response and Failure Evaluation of Tapered Composite Components under Multiaxial Loading

2021 ◽  
Author(s):  
Jian Xiao ◽  
Phillip Liu ◽  
D.C. Pham ◽  
Jim Lua ◽  
Shenal Perera ◽  
...  
Keyword(s):  
High Fidelity ◽  
Multiaxial Loading ◽  
Failure Evaluation
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