Simulating Hypervelocity Impact and Material Failure in Glass

2018 ◽  
Author(s):  
Andrew J. Birnbaum ◽  
John C. Steuben ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos
Keyword(s):  
Strain Rate ◽  
Soda Lime ◽  
Material Model ◽  
Hypervelocity Impact ◽  
Shock Propagation ◽  
Material Failure ◽  
Explicit Finite Element ◽  
Static Responses ◽  
Inherent Strain ◽  
Permanent Densification

Simulating hypervelocity impact introduces a host of complexities due to inherent strain, pressure and strain rate sensitivities. Brittle materials, and glasses in particular, exhibit significant deviations from their respective quasi-static responses, displaying permanent densification, gradual softening, and significant variation in response depending on the degree of material damage. This work seeks to examine the evolution of material failure due to hypervelocity impact of a spherical steel projectile in to a soda-lime target plate over a range of impact velocities via the utilization of a scalable, explicit finite element code, Velodyne, and a high strain rate, brittle material model. It is shown that, by analyzing both the evolutionary instantaneous and accumulated failure behaviors, the resulting performance is profoundly effected by target/projectile geometries, as well as the complex behaviors observed with respect to shock propagation, reflection and interference.

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.

Influence of strain rate, temperature and fatigue on the radial compression behaviour of Norway spruce

Holzforschung ◽  
2017 ◽  
Vol 71 (6) ◽  
pp. 505-514 ◽  
Author(s):  
Carolina Moilanen ◽  
Tomas Björkqvist ◽  
Markus Ovaska ◽  
Juha Koivisto ◽  
Amandine Miksic ◽  
...  
Keyword(s):  
Strain Rate ◽  
Linear Model ◽  
Norway Spruce ◽  
Material Model ◽  
Radial Compression ◽  
Compression Tests ◽  
Static Compression ◽  
Rate Dependent ◽  
Compression Model ◽  
Wood Compression

Abstract A dynamic elastoplastic compression model of Norway spruce for virtual computer optimization of mechanical pulping processes was developed. The empirical wood behaviour was fitted to a Voigt-Kelvin material model, which is based on quasi static compression and high strain rate compression tests (QSCT and HSRT, respectively) of wood at room temperature and at high temperature (80–100°C). The effect of wood fatigue was also included in the model. Wood compression stress-strain curves have an initial linear elastic region, a plateau region and a densification region. The latter was not reached in the HSRT. Earlywood (EW) and latewood (LW) contributions were considered separately. In the radial direction, the wood structure is layered and can well be modelled by serially loaded layers. The EW model was a two part linear model and the LW was modelled by a linear model, both with a strain rate dependent term. The model corresponds well to the measured values and this is the first compression model for EW and LW that is based on experiments under conditions close to those used in mechanical pulping.

Strength Simulation of Woven Fabric Composite Materials With Material Nonlinearity Using Micromechanics Based Model

2000 ◽  
Author(s):  
A. Tabiei ◽  
G. Song ◽  
Y. Jiang
Keyword(s):  
Finite Element ◽  
Shear Failure ◽  
Material Model ◽  
Failure Criteria ◽  
Woven Fabric ◽  
Woven Composites ◽  
Explicit Finite Element ◽  
Representative Cell ◽  
Pure Matrix ◽  
Transverse Failure

Abstract The objective of the current investigation is to predict failure strength of woven composites, which considers the two-dimensional extent of woven fabric, based on micro-mechanics. The formulation has an interface with nonlinear finite element codes. At each load increment, global stresses and strains are communicated to the representative cell and subsequently distributed to each subcell. Once stresses and strains are associated to a subcell they can be distributed to each constituent of the subcell (i.e. fill, warp, and resin). Consequently micro-failure criteria (MFC) are defined for each constituents of a subcell and the proper stiffness degradation is modeled. Different stages of failure such as warp transverse failure, fill transverse failure, failure of pure matrix in longitudinal and shear, shear failure in fill and warp, and fiber in fill and warp in longitudinal tension are considered. Good correlation is observed between the predicted and the experimental results presented in the published literature. This material model is suitable for implicit failure analysis under static loads and is being modified for explicit finite element codes to deal with problems such as crashworthiness and impact.

Finite Element Modeling of Non-Orthogonal Loosely Woven Fabrics in Advanced Occupant Restraint Systems

2001 ◽  
Author(s):  
Romil R. Tanov ◽  
Marlin Brueggert
Keyword(s):  
Finite Element ◽  
Material Model ◽  
General Purpose ◽  
Woven Fabrics ◽  
Element Analysis ◽  
Correct Operation ◽  
Explicit Finite Element ◽  
Analysis Scheme ◽  
Occupant Restraint Systems ◽  
Protection Devices

Abstract The behavior of loosely woven fabrics differs significantly from other types of woven fabrics. Its unique characteristics have been successfully utilized for the correct operation of some recently developed occupant protection devices for the automotive and heavy machine and truck industry. However, this behavior cannot be efficiently modeled using the currently available material models within a finite element analysis scheme. Therefore, the aim of this work is to present the basics of a formulation of a material model for the analysis of loosely woven fabrics and its implementation in a general-purpose explicit finite element code. To assess the performance of the model, results from the simulation are presented and compared to real test data.

scholarly journals Fatigue life time modelling of Cu and Au fine wires

2018 ◽  
Vol 165 ◽  
pp. 06002
Author(s):  
Golta Khatibi ◽  
Ali Mazloum-Nejadari ◽  
Martin Lederer ◽  
Mitra Delshadmanesh ◽  
Bernhard Czerny
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Load Ratio ◽  
Life Time ◽  
Material Model ◽  
Cycle Fatigue ◽  
Rate Dependency

In this study, the influence of microstructure on the cyclic behaviour and lifetime of Cu and Au wires with diameters of 25μm in the low and high cycle fatigue regimes was investigated. Low cycle fatigue (LCF) tests were conducted with a load ratio of 0.1 and a strain rate of ~2e-4. An ultrasonic resonance fatigue testing system working at 20 kHz was used to obtain lifetime curves under symmetrical loading conditions up to very high cycle regime (VHCF). In order to obtain a total fatigue life model covering the low to high cycle regime of the thin wires by considering the effects of mean stress, a four parameter lifetime model is proposed. The effect of testing frequency on high cycle fatigue data of Cu is discussed based on analysis of strain rate dependency of the tensile properties with the help of the material model proposed by Johnson and Cook.

A simple ballistic material model for soda-lime glass

2009 ◽  
Vol 36 (3) ◽  
pp. 386-401 ◽  
Author(s):  
M. Grujicic ◽  
B. Pandurangan ◽  
N. Coutris ◽  
B.A. Cheeseman ◽  
C. Fountzoulas ◽  
...  
Keyword(s):  
Soda Lime ◽  
Material Model ◽  
Soda Lime Glass

Microplane Model for Fracturing Damage of Triaxially Braided Fiber-Polymer Composites

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Ferhun C. Caner ◽  
Zdeněk P. Bažant ◽  
Christian G. Hoover ◽  
Anthony M. Waas ◽  
Khaled W. Shahwan
Keyword(s):  
Present Model ◽  
Material Model ◽  
Multiscale Model ◽  
Stress And Strain ◽  
Band Model ◽  
Braided Composites ◽  
Microplane Model ◽  
Explicit Finite Element ◽  
Crack Band ◽  
Strain Tensors

A material model for the fracturing behavior for braided composites is developed and implemented in a material subroutine for use in the commercial explicit finite element code ABAQUS. The subroutine is based on the microplane model in which the constitutive behavior is defined not in terms of stress and strain tensors and their invariants but in terms of stress and strain vectors in the material mesostructure called the “microplanes.” This is a semi-multiscale model, which captures the interactions between inelastic phenomena such as cracking, splitting, and frictional slipping occurring on planes of various orientations though not the interactions at a distance. To avoid spurious mesh sensitivity due to softening, the crack band model is adopted. Its band width, related to the material characteristic length, serves as the localization limiter. It is shown that the model can realistically predict the orthotropic elastic constants and the strength limits. More importantly, the present model can also fit the tests of size effect on the strength of notched specimens and the post-peak behavior, which have been conducted for this purpose. When used in the ABAQUS software, the model gives a realistic picture of the axial crushing of a braided tube by a divergent plug.

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