Elemental Water Impact Test: Phase 3 Plunge Depth of a 36-Inch Aluminum Tank Head

Spacecraft are being designed based on LS-DYNA water landing simulations. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 3 featured a composite tank head that was tested at a range of heights to verify the ability to predict structural failure of composites. To support planning for Phase 3, a test series was conducted with an aluminum tank head dropped from heights of 2, 6, 10, and 12 feet to verify that the test article would not impact the bottom of the test pool. This report focuses on the comparisons of the measured plunge depths to LS-DYNA predictions. The results for the tank head model demonstrated the following. 1. LS-DYNA provides accurate predictions for peak accelerations. 2. LS-DYNA consistently under-predicts plunge depth. An allowance of at least 20% should be added to the LS-DYNA predictions. 3. The LS-DYNA predictions for plunge depth are relatively insensitive to the fluid-structure coupling stiffness

Ability of ANSYS/LS-DYNA software for simulation of mechanoprocessing

Рассмотрены функциональные возможности программного комплекса ANSYS/LS-DYNA для моделирования процессов механической обработки конструкционных материалов, а также роль внедрения актуальных компьютерных программ в современном учебном процессе.The paper describes the functionality of the software package ANSYS/LS-DYNA for the structural materials machining simulation, also applying of the new computer programs in the modern educational process have been discussed

Numerical simulation of impact with the barriers

Hlavním cílem dané práce je provedení numerické simulace v programovém prostředí ANSYS LS-DYNA. Pro tyto účely byly zvoleny dva typy silničních svodidel s úrovní zadržení H2: JSNH4/H2 a JSAM-2/H2. Cíl dané práce úzce souvisí s dílčími úkoly, mezi kterými je sestavení výpočtových modelů, nastavení příslušných parametrů modelů, provedení výpočtů, vyhodnocení a porovnání dosažených výsledků. V dané práce byly použity programy ANSYS Workbench a LS-DYNA. Na základě stanovené síly nárazu, výsledného průhybu jednotlivých částí konstrukce a vypočtené vnitřní energie bylo provedeno vyhodnocení výsledků.The main aim of the present master's thesis is to perform numerical simulation in ANSYS LS-DYNA. For these purposes two types of safety barriers are used: JSNH4/H2 and JSAM-2/H2. The aim is closely connected with such objectives as safety barrier geometrical model creation, setting parameters of crash tests, calculation performance, data analysis and results evaluation. In this work ANSYS Workbench and LS-DYNA have been used. On the basis of impact forces, body displacement and internal energy obtained during numerical simulation the results evaluation is fulfilled

К вопросу создания интегрированных специализированных систем для моделирования процессов пробивания преград

У статті описано ефективну технологію автоматизації досліджень процесу пробиття бронеперешкод. Створено методику та спеціалізований модуль, що інтегрує розрахунки в системах ANSYS, LS-DYNA. Проведено тестові розрахунки.In the article effective technology of automation of research process of armor obstacles breaching is described. A method and specialized module which integrates calculationsin ANSYS and LS-DYNA systems are created. Test computations are conducted

Dynamic delamination of aeronautic structural composites by using cohesive finite elements

Cohesive finite elements are used to model impact induced delamination prediction of T800/21M unidirectional laminated composite. DCB, ELS and MMB tests are used to identify cohesive element parameters. Results from experiments and numerical prediction of impact induced delamination by commercially available code LS-DYNA are compared

Benchmarking of three parallelized implementations of LS-Dyna on a HPC server cluster

This paper discusses the benchmarking of three parallelized implementations of the popular LS-Dyna® finite element code (Livermore Software Technology Corp.) on the STePS2 high performance computing (HPC) server cluster. SMP, MPP and SMP-MPP hybrid implementations of LS-Dyna® are benchmarked over various numbers of nodes, cpus and cpu cores. The STePS2 HPC cluster consists of a dual-cpu head node and 16 homogeneous dual-cpu compute nodes. All nodes are interconnected via an Infiniband® network fabric. All cpus are quad-core Intel Xeon 64-bit and the operating system(s) is the ROCKS cluster management software implemented through Redhat Enterprise Linux 5 (x86_64). SMP, MPP and MPP-SMP hybrid implementations of LS-Dyna were compiled for use with the HPMPI message passing interface

Quasi-Static 3-Point Reinforced Carbon-Carbon Bend Test and Analysis for Shuttle Orbiter Wing Leading Edge Impact Damage Thresholds

Static 3-point bend tests of Reinforced Carbon-Carbon (RCC) were conducted to failure to provide data for additional validation of an LS-DYNA RCC model suitable for predicting the threshold of impact damage to shuttle orbiter wing leading edges. LS-DYNA predictions correlated well with the average RCC failure load, and were good in matching the load vs. deflection. However, correlating the detectable damage using NDE methods with the cumulative damage parameter in LS-DYNA material model 58 was not readily achievable. The difficulty of finding internal RCC damage with NDE and the high sensitivity of the mat58 damage parameter to the load near failure made the task very challenging. In addition, damage mechanisms for RCC due to dynamic impact of debris such as foam and ice and damage mechanisms due to a static loading were, as expected, not equivalent

The influence of joints and composite floor slabs on effective tying of steel structures in preventing progressive collapse

The event of the terrorist attack at 11th September 2001 in the USA has attracted increasing attention of researchers and engineers on progressive collapse of structures. It has gradually become a general practice for engineers to consider progressive collapse resistance in their design. In this paper, progressive collapse of steel frames with composite floor slabs is simulated by the finite element method. The numerical results are compared with test results. The influence of the joints and the concrete slabs on the effective tying of steel beams is investigated through parametric studies. From the analysis, methods of preventing progressive collapse that can be considered in design and when retrofitting existing structures are proposed. The results show that retrofitting a structure with pre-stressed steel cables and an increase of crack resistance in the concrete near joints can effectively improve effective tying of a structure, which results in an enhanced structural capacity in preventing progressive collapse

On the response of impacting compliant flex run

Damage caused by impacts of structures can result in catastrophic failure, including huge loss of life. A typical example involves a Flexrun which is particularly vulnerable to several impacts on the ground surface. It is, therefore, becoming increasingly important to be able to model and predict such phenomena. The impact of an impacting compliant system such as a Flexrun on the ground surface is simulated by the general purpose explicit dynamic finite element program LS-DYNA. The complicated geometry has been modeled in Solid Edge ST6 before being imported into LS PrePost/LS-DYNA for the required analysis. The response characteristics of the Flexrun show the effect of impacting velocity on strain and stress histories of the mechanism. Results reveal that within the impacting velocity of 15m/s, the effective stress and strain responses remain unchanged.Keywords: compliant mechanism, impact-contact, LS-DYNA, hyperelastic, Flex-Ru

Sheet forming simulations of automotive parts using different yield functions

In this work, the influence of the yield function on finite element (FE) forming simulation results for two auto-body panels, hood inner and door outer, was investigated. Simulations were conducted with different yield functions, Hill's1948. Yld91 and Yld2000-2d, which are available in the PAM-STAMP and LS-DYNA commercial codes. Although moderate, some differences in the results were observed.open111Nsciescopu