Finite Element Simulation of Damage Evolution in Dynamically Loaded Structures

2009 ◽  
Author(s):  
R. Schmidt ◽  
M. Stoffel
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Damage Evolution ◽  
Element Simulation ◽  
Dynamically Loaded

Numerical simulation of ductile fracture in polyethylene pipe with continuum damage mechanics and Gurson-Tvergaard-Needleman damage models

2019 ◽  
Vol 233 (12) ◽  
pp. 2455-2468
Author(s):  
Yi Zhang ◽  
P-Y Ben Jar ◽  
Shifeng Xue ◽  
Lin Li
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Constitutive Equations ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Experimental Testing ◽  
Monotonic Loading ◽  
Test Method ◽  
Strain Level ◽  
Element Simulation

A phenomenon-based hybrid approach of experimental testing and finite element simulations is used to describe the fracture behavior of pipe-grade polyethylene. The experimental testing adopts a modified D-split test method to stretch the pipe ring (notched pipe ring) specimens that have symmetric, double-edged flat notches along the pipe direction. Two series of experimental testing were conducted: (1) monotonic loading till fracture and (2) monotonic loading to a predefined strain level, keeping constant displacement for a period of time, and then unloaded. Crosshead speeds of 0.01, 1, and 100 mm/min were used in both series of tests. Likewise, two series of finite element simulation were conducted to establish the constitutive equations, either with or without considering damage evolution during the deformation process. The constitutive equation without the consideration of damage was established using results from the first series of experimental testing, and that with damage was inspired from the second series which showed the decrease in unloading modulus with the increase of crosshead speed or the predefined strain level. The results show that with the consideration of damage evolution, the constitutive equations enable the finite element simulation to determine the whole stress–strain relationship during both necking and fracture processes.

Behavior of polyethylene under different triaxial stress states: An experimental and numerical study

2020 ◽  
pp. 146442072097058
Author(s):  
Limei Han ◽  
Yi Zhang ◽  
Shifeng Xue ◽  
Bo Zhou ◽  
Cuiwei Liu
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Damage Evolution ◽  
Fracture Strain ◽  
Damage Model ◽  
Stress Triaxiality ◽  
True Stress ◽  
Triaxial Stress ◽  
Element Simulation ◽  
Stress States

The behavior of a semi-crystalline polymer under different triaxial stress states is studied through the combination of experimental testing and finite element simulation. Polyethylene round bar specimens with four different notch radii were stretched at crosshead speed of 1 mm/min until fracture. The continuum damage mechanics damage model and Gurson–Tvergaard–Needleman damage model were proposed and applied to the finite element simulation. The results of engineering stress–displacement curves determined from finite element simulation match experimental results. Finite element simulation without considering damage and with the consideration of damage was conducted to determine the damaged and undamaged true stress–strain relationship of polyethylene materials, respectively. Damage evolution model was established based on the degradation of true stress. The finite element model was further applied to study the distribution of stress triaxiality for specimens with different notch radii and the effect of stress triaxiality on damage evolution, critical damage parameters, and fracture strain. The results show that the distribution of the stress triaxiality on the cross section of the specimen is not uniform, and as the stress triaxiality increases, the position where the maximum stress triaxiality occurs moves from the center point to two-third the radius from the center. Furthermore, the damaged true stress and the undamaged true stress increases with the decrease of the stress triaxiality when the strain is below 0.3, but decreases with the increase of stress triaxiality when the strain is larger than 0.3. In addition, it was found that the greater the stress triaxiality, the earlier the onset of damage and the faster the evolution, but the smaller the fracture strain.

scholarly journals Effect of Stress Triaxiality on Plastic Damage Evolution and Failure Mode for 316L Notched Specimen

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1067 ◽  
Author(s):  
Peng ◽  
Wang ◽  
Dai ◽  
Liu ◽  
Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Failure Mode ◽  
Damage Evolution ◽  
Stress Triaxiality ◽  
Image Correlation ◽  
Void Coalescence ◽  
Notched Specimen ◽  
Plastic Damage ◽  
Element Simulation

To reveal the effect of stress triaxiality on plastic damage evolution and failure mode, 316L notched specimens with different notch sizes are systematically investigated by digital image correlation (DIC) observation, plastic damage analysis by finite element simulation, and void mesoscopic observation. It was found that the plastic damage evolution and failure mode are closely related with notch radius and stress triaxiality. The greater the stress triaxiality at the root is, the greater the damage value at the root is and the earlier the fracture occurs. Moreover, void distribution by mesoscopic observation agrees well with damage distribution observed by finite element simulation with the Gurson-Tvergaard-Needleman (GTN) damage model. It is worth noting that, with the increase in stress triaxiality, the failure mode of notched specimen changes from ductility fracture with void coalescence at the center position to crack initiation at the notch root, from both mesoscopic observation and damage simulation.

Sign in / Sign up

Export Citation Format

Share Document