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.

Energy-based numerical modeling of the strain rate effect on fracture toughness of SA508 Gr. 1a

2017 ◽  
Vol 52 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Jong-Sung Kim
Keyword(s):  
Fracture Toughness ◽  
Strain Rate ◽  
Damage Model ◽  
Type Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Rate Dependent ◽  
Energy Concept ◽  
Axial Fracture ◽  
Dynamic Loading Conditions

This article presents an energy-based method to simulate ductile tearing under dynamic loading conditions. The strain rate–dependent material properties are characterized by the Johnson–Cook-type model. The damage model is defined based on the multi-axial fracture strain energy concept. The proposed damage model is applied to simulate the fracture toughness test of SA508 Gr. 1a under four different test speeds. Simulated results show a good overall agreement with the experimental results.

Changing the Hardness Automotive Steels at Different Strain Rate

2014 ◽  
Vol 635 ◽  
pp. 41-44
Author(s):  
Miroslav Német ◽  
Mária Mihaliková ◽  
Alexandra Kovalčíkova ◽  
Anna Lišková
Keyword(s):  
Strain Rate ◽  
Dynamic Loading ◽  
Automotive Industry ◽  
Interstitial Free ◽  
Loading Conditions ◽  
Product Testing ◽  
Dynamic Conditions ◽  
Interstitial Free Steel ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading

Currently, the automotive industry used sheets of different qualities. The most common include IF (inter Interstitial Free) steel and alloyed steel. Use the sheet quality depends on the point of application in the production car. Testing and product testing is a standard part of the process of innovation and production itself. Testing of automotive steels under dynamic conditions is increasingly important. Changing the hardness HV 1 was performed on the fractured bars on the static and dynamic loading conditions. Tests were made on steel IF and S 460.

Evaluation of Friction at High Strain Rate using the Split Hopkinson Bar

2015 ◽  
Vol 651-653 ◽  
pp. 108-113 ◽  
Author(s):  
Archimede Forcellese ◽  
Edoardo Mancini ◽  
Marco Sasso ◽  
Michela Simoncini
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strain ◽  
Outer Diameter ◽  
Loading Conditions ◽  
Split Hopkinson ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading ◽  
Frictional Behaviour

The present work aims at studying the influence of strain rate on the frictional behaviour of AA7075 aluminium alloy in the O-annealed temper state. To this purpose, ring compression tests were performed both under quasi-static and dynamic loading conditions. The high strain rate tests were carried out by means of the Split Hopkinson Tension-Compression Bar in the direct version. In both cases, hollow cylindrical samples, characterised by an initial outer diameter to inner diameter to height ratio of 6:3:2, were tested under dry condition and by lubricating with molybdenum disulphide grease. The different frictional behaviour exhibited by AA7075-O under quasi-static and dynamic loading conditions can be attributed to the strain rate effect both on the plastic flow behaviour of the deformed material, and on the thickness of the lubricant film.

Ductile Fracture Simulation Considering Strain Rate Loading Effect

2015 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Chang-Young Oh
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Dynamic Loading ◽  
Fracture Strain ◽  
Fracture Toughness Test ◽  
Loading Conditions ◽  
Loading Effect ◽  
Fracture Simulation ◽  
Dynamic Loading Conditions ◽  
Strain Model

This paper is based on a ductile failure simulation under dynamic loading conditions using finite element (FE) analyses. Recently a simple finite element method in a quasi-static test has been proposed to implement fracture simulation based on the well-known stress modified fracture strain model. The stress-modified fracture strain model is determined to be incremental damage in terms of stress triaxiality and fracture strain for dimple fracture from tensile test result with FE analyses technique. Since dynamic loading effect is especially important to assess pipe with crack-like defect, this work propose the integrated model which combines quasi-static with dynamic loading effect. In order to validate stress-modified fracture strain model in dynamic loading conditions, this paper compares results of FE analysis using proposed method with strain dependent smooth bar tests and notch tensile tests using Johnson-Cook equation. In conclusion, the stress-modified fracture strain model criterion can be calibrated by FE analyses with strain rate dependent fracture toughness test results.

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