Ductile Fracture under Dynamic Loading using a Strain-Rate Dependent Cohesive Model

2009 ◽  
Author(s):  
M. Anvari ◽  
I. Scheider ◽  
C. Thaulow
Keyword(s):  
Strain Rate ◽  
Ductile Fracture ◽  
Dynamic Loading ◽  
Cohesive Model ◽  
Rate Dependent

scholarly journals Numerical Study on the Dynamic Fracture Energy of Concrete Based on a Rate-Dependent Cohesive Model

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7421
Author(s):  
Penglin Zhang ◽  
Zhijun Wu ◽  
Yang Liu ◽  
Zhaofei Chu
Keyword(s):  
Strain Rate ◽  
Fracture Energy ◽  
Dynamic Fracture ◽  
Loading Rate ◽  
Numerical Study ◽  
Damage Zone ◽  
Concrete Fracture ◽  
Obvious Effect ◽  
Cohesive Model ◽  
Rate Dependent

As an important parameter for concrete, fracture energy is difficult to accurately measure in high loading rate tests due to the limitations of experimental devices and methods. Therefore, the utilization of numerical methods to study the dynamic fracture energy of concrete is a simple and promising choice. This paper presents a numerical investigation on the influence of loading rate on concrete fracture energy and cracking behaviors. A novel rate-dependent cohesive model, which was programmed as a user subroutine in the commercial explicit finite element solver LS-DYNA, is first proposed. After conducting mesh sensitivity analysis, the proposed model is calibrated against representative experimental data. Then, the underlying mechanisms of the increase in fracture energy due to a high strain rate are determined. The results illustrate that the higher fracture energy during dynamic tension loading is caused by the wider region of the damage zone and the increase in real fracture energy. As the loading rate increases, the wider region of the damage zone plays a leading role in increasing fracture energy. In addition, as the strain rate increases, the number of microcracks whose fracture mode is mixed mode increases, which has an obvious effect on the change in real fracture energy.

scholarly journals Anisotropic, rate-dependent ductile fracture of Ti-6Al-4V alloy

2021 ◽  
pp. 105678952110364
Author(s):  
Miguel Ruiz de Sotto ◽  
Véronique Doquet ◽  
Patrice Longère ◽  
Jessica Papasidero
Keyword(s):  
Strain Rate ◽  
Ductile Fracture ◽  
Stress Triaxiality ◽  
Clear Correlation ◽  
Local Loading ◽  
Lode Parameter ◽  
Absolute Value ◽  
Rate Dependent ◽  
Insight Into ◽  
Tension Maximum

An extensive experimental campaign was run to investigate the influence of the loading direction, stress state (triaxiality ratio ranging from −0.5 to 1), and strain rate (from 10−3 to 1.5x103s−1) on the ductile fracture of Ti-6Al-4V titanium alloy. Microscopic and macroscopic observations provided some insight into the shear-driven or micro-voiding-controlled damage mechanisms prevailing at low and high triaxiality ratios, respectively. Numerical simulations were run to determine the local loading paths to fracture in terms of plastic strain as a function of stress triaxiality ratio and Lode parameter. The ductility was found to be anisotropic, but only weakly dependent on the strain rate in the considered range. The anisotropy in ductility was different in tension (maximum along DD) and in compression (maximum along ND). The fracture strain decreased with the absolute value of the triaxiality, with a maximum close to zero. No clear correlation with the Lode parameter was found.

Stress-state and strain-rate dependent ductile fracture of dual and complex phase steel

2018 ◽  
Vol 116 ◽  
pp. 11-32 ◽  
Author(s):  
Borja Erice ◽  
Christian C. Roth ◽  
Dirk Mohr
Keyword(s):  
Stress State ◽  
Strain Rate ◽  
Ductile Fracture ◽  
Complex Phase ◽  
Rate Dependent

scholarly journals Rate Dependent Multicontinuum Progressive Failure Analysis of Woven Fabric Composite Structures under Dynamic Impact

2004 ◽  
Vol 11 (2) ◽  
pp. 103-117 ◽  
Author(s):  
James Lua ◽  
Christopher T. Key ◽  
Shane C. Schumacher ◽  
Andrew C. Hansen
Keyword(s):  
Composite Materials ◽  
Strain Rate ◽  
Dynamic Loading ◽  
Damage Model ◽  
Woven Fabric ◽  
Loading Conditions ◽  
Rate Dependent ◽  
Fabric Composite ◽  
Dynamic Loading Conditions ◽  
Marine Composite

Marine composite materials typically exhibit significant rate dependent response characteristics when subjected to extreme dynamic loading conditions. In this work, a strain-rate dependent continuum damage model is incorporated with multicontinuum technology (MCT) to predict damage and failure progression for composite material structures. MCT treats the constituents of a woven fabric composite as separate but linked continua, thereby allowing a designer to extract constituent stress/strain information in a structural analysis. The MCT algorithm and material damage model are numerically implemented with the explicit finite element code LS-DYNA3D via a user-defined material model (umat). The effects of the strain-rate hardening model are demonstrated through both simple single element analyses for woven fabric composites and also structural level impact simulations of a composite panel subjected to various impact conditions. Progressive damage at the constituent level is monitored throughout the loading. The results qualitatively illustrate the value of rate dependent material models for marine composite materials under extreme dynamic loading conditions.

Strain-rate dependent material properties of selective laser melted AlSi10Mg and AlSi3.5Mg2.5

2020 ◽  
Vol 62 (6) ◽  
pp. 573-583
Author(s):  
Andreas Lutz ◽  
Lukas Huber ◽  
Claus Emmelmann
Keyword(s):  
Strain Rate ◽  
Material Properties ◽  
Rate Dependent

Strain-Rate Dependent Deformation Behavior in WC-10 wt%Ni 3Al Cermet Micropillars Under Uniaxial Compression

2019 ◽  
Author(s):  
Minai Zhang ◽  
Xin Wang ◽  
Alexander D. Dupuy ◽  
Julie M. Schoenung ◽  
Xiaoqiang Li
Keyword(s):  
Strain Rate ◽  
Uniaxial Compression ◽  
Deformation Behavior ◽  
Rate Dependent

scholarly journals Identification of the LLDPE Constitutive Material Model for Energy Absorption in Impact Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1537
Author(s):  
Luděk Hynčík ◽  
Petra Kochová ◽  
Jan Špička ◽  
Tomasz Bońkowski ◽  
Robert Cimrman ◽  
...  
Keyword(s):  
Strain Rate ◽  
Material Model ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Stress Strain ◽  
Rate Dependent ◽  
Constitutive Material Model ◽  
Principal Directions ◽  
Constitutive Material

Current industrial trends bring new challenges in energy absorbing systems. Polymer materials as the traditional packaging materials seem to be promising due to their low weight, structure, and production price. Based on the review, the linear low-density polyethylene (LLDPE) material was identified as the most promising material for absorbing impact energy. The current paper addresses the identification of the material parameters and the development of a constitutive material model to be used in future designs by virtual prototyping. The paper deals with the experimental measurement of the stress-strain relations of linear low-density polyethylene under static and dynamic loading. The quasi-static measurement was realized in two perpendicular principal directions and was supplemented by a test measurement in the 45° direction, i.e., exactly between the principal directions. The quasi-static stress-strain curves were analyzed as an initial step for dynamic strain rate-dependent material behavior. The dynamic response was tested in a drop tower using a spherical impactor hitting a flat material multi-layered specimen at two different energy levels. The strain rate-dependent material model was identified by optimizing the static material response obtained in the dynamic experiments. The material model was validated by the virtual reconstruction of the experiments and by comparing the numerical results to the experimental ones.

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