Simulations of crack propagation in elastic–plastic graded materials

2004 ◽  
Vol 36 (7) ◽  
pp. 601-622 ◽  
Author(s):  
Zhiqiang Wang ◽  
Toshio Nakamura
Keyword(s):  
Crack Propagation ◽  
Graded Materials ◽  
Elastic Plastic

Inverse Analysis to Estimate Critical Crack Propagation Parameters for Elastic-Plastic and Graded Materials

2004 ◽  
Vol 261-263 ◽  
pp. 117-122
Author(s):  
Toshio Nakamura ◽  
Zi Qiang Wang
Keyword(s):  
Crack Propagation ◽  
Inverse Analysis ◽  
Crack Opening ◽  
Reaction Force ◽  
Accurate Estimation ◽  
Crack Advance ◽  
Inhomogeneous Materials ◽  
Graded Materials ◽  
Elastic Plastic ◽  
Fracture Parameters

Accurate crack propagation simulation requires critical fracture parameters to be known a priori. For elastic-plastic materials, two fundamental parameters are the separation energy and the peak stress required to generate new crack surfaces. In general, both are difficult to quantify since direct determinations are not possible in experiments. For inhomogeneous materials, such as graded materials, determination is even more complex since these parameters vary spatially. In this paper, a novel method based on an inverse analysis technique is proposed to estimate the fracture parameters of elastic-plastic and graded media. The method utilizes the Kalman filter to process measured data and extract best estimates of the unknown parameters. The accuracy of the method is examined in a verification study where a dynamically propagating crack in double cantilever beam type specimen is modeled. In the study, time variation records of crack opening displacement, opening strain, crack advance distance, and load point reaction force are used as possible measurements. Despite large noises in data, the results confirm accurate estimation. The estimates improve when multiple measurements are supplied to the inverse technique.

scholarly journals Comparative modelling of crack propagation in elastic–plastic materials using the meshfree local radial basis point interpolation method and eXtended finite-element method

2019 ◽  
Vol 6 (11) ◽  
pp. 190543 ◽  
Author(s):  
Yazhe Li ◽  
Nengxiong Xu ◽  
Jinzhi Tu ◽  
Gang Mei
Keyword(s):  
Finite Element Method ◽  
Crack Propagation ◽  
Extended Finite Element Method ◽  
Interpolation Method ◽  
Extended Finite Element ◽  
Elastic Plastic ◽  
Plastic Materials ◽  
Point Interpolation Method ◽  
Point Interpolation ◽  
Elastic Plastic Materials

The modelling and understanding of crack propagation for elastic–plastic materials is critical in various engineering applications, such as safety analysis of concrete structures and stability analysis of rock slopes. In this paper, the local radial basis point interpolation method (LRPIM) combined with elastic–plastic theory and fracture mechanics is employed to analyse crack propagation in elastic–plastic materials. Crack propagation in elastic–plastic materials is compared using the LRPIM and eXtended finite-element method (XFEM). The comparative investigation indicates that: (i) the LRPIM results are close to the model test results, which indicates that it is feasible for analysing the crack growth of elastic–plastic materials; (ii) compared with the LRPIM, the XFEM results are closer to the experimental results, showing that the XFEM has higher accuracy and computational efficiency; and (iii) compared with the XFEM, when the LRPIM method is used to analyse crack propagation, the propagation path is not smooth enough, which can be explained as the crack tip stress and strain not being accurate enough and still needing further improvement.

scholarly journals Study on Thermally Induced Crack Propagation Behavior of Functionally Graded Materials Using a Modified Peridynamic Model

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Fei Wang ◽  
Yu’e Ma ◽  
Yanning Guo ◽  
Wei Huang
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Functionally Graded Materials ◽  
Initial Temperature ◽  
Functionally Graded ◽  
Thermal Crack ◽  
Graded Materials ◽  
Ceramic Fracture ◽  
Thermally Induced ◽  
Peridynamic Model

Peridynamic (PD) theory is used to study the thermally induced cracking behavior of functionally graded materials (FGMs). A modified thermomechanical peridynamic model is developed. The thermal crack propagation of a ceramic slab in quenching is calculated to validate the modified PD model. The results predicted by the modified PD model agree with previously published numerical and experimental ones. Compared with the original PD model, the calculation accuracy of the modified PD model for thermal cracking is improved. The thermal cracking in FGMs is also simulated. The effects of material shape, initial temperature, and ceramic fracture toughness on thermal crack propagation behaviors are studied. It can be found that the thermal cracks in FGMs are still in periodical and hierarchical forms. The metal materials in FGMs can prevent crack initiation and arrest the long cracks. The crack number tends to be increased with the increasing initial temperature, while the strengthened ceramic fracture toughness can decrease it.

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