Crash analysis and energy absorption characteristics of S-shaped longitudinal members

Pirmohammad

Lat. Am. j. solids struct.

2017

To mitigate shock forces in collision events, thin-walled members are used as energy absorber. In this article, crashworthiness of single-cell and multi-cell S-shaped members with various crosssections including triangular, square, hexagonal, decagon and circular were investigated under axial dynamic loading using finite element code LS-DYNA. Furthermore, crashworthiness of the S-rails with the same outer tubes and different inner ones was studied as well. The multi-cell members employed in this task were doublewalled tubes with several ribs connecting the inner and outer tubes together. Modified multi criteria decision making method known as complex proportional assessment (COPRAS) was used to rank the members using three conflicting crashworthiness criteria namely specific energy absorber (SEA), peak crash force (Fmax) and crash force efficiency (CFE). Moreover, the multi-cell S-shaped members were found to perform better than single-cell ones in terms of crashworthiness. In addition, the multi-cell S-rail with decagonal cross-section was found as the best energy absorber, and also the Srail having the same inner and outer tube with decagonal crosssection displayed desirable crashworthiness performance. Optimum geometry of this S-rail was eventually obtained from the parametric study.

Section: Parametric Studysupporting

confidence: 62%

Crashworthiness Analysis of S-Shaped Structures Under Axial Impact Loading

Pirmohammad

Lat. Am. j. solids struct.

2017

Journal of Al-Azhar University Engineering Sector

“…The Ford finite element model of NHTSA [1] is an LS-DYNA input deck. The LS-DYNA finite element software is considered industry standard for both crash simulation and modeling [16]. ANSYS LS-DYNA [21] offers much higher usability especially for ANSYS user base.…”

Section: Finite Element Modelmentioning

confidence: 99%

“…The total weight is about 1782 kg [14]. The Shell elements [16], integration points through thickness [16], and spot welds [16, 17, and 18] are also changed to speed up the calculations and reduce the simulation run time on the computer. These changes are shown below in Table 1.…”

Section: Finite Element Modelmentioning

confidence: 99%

See 1 more Smart Citation

On the Evaluation of “Nhtsa” Automotive Fe Model in Head on Crash Using Ansys Ls-Dyna System Against “Iihs” Test.

Salem

2019

Simulations of automotive crash are now a well-established instrument for ensuring occupants safety at most types of crash scenarios and improving the car design accordingly when needed. Many Automotive crash simulation's systems are available currently, where each system strives to attain ease of use, high accuracy, and consuming the least possible computer time in running the crash scenario. However, most of these systems are used independently. A unique exception of these systems is ANSYS LS-DYNAYwhere the two systems can be used as one unit in ANSYS explicit module, where one can combine the ease of use of ANSYS with the world class suite of LS-DYNA.This system is quite straightforward to modify the car model, change elements attributes, redefine the elements integration rule, and spotweld definitions to achieve less running time while keeping almost the same accuracy. This paper presents an evaluation of a modified National Highway Traffic Safety Administration (NHTSA) finite element model of Ford truck structure.The model structure is first imported to ANSYS LS-DYNA simulation system to facilitate its handling, modification, and applying different simulation scenarios. Then after modification, it is evaluated through the following three steps: first, evaluated against the ability to rollover almost free of stresses, second, evaluated in a head on crash test at low speeds such as 5 miles/hours.This scenario can happen while moving out of the drive way or in a parking lot area, and third, evaluated in a head on crash test against rigid fixed barrier with 35 miles/hour test simulating the Insurance institute for highway safety (IIHS) test. The results show that the modified model is quite capable of capturing the main characteristics of the three tests adequately.

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

“…[17,18]. Enerji sönümleyicilerinin içerisini hücreli [19,20] bir yapıda yapmak veya köpük malzemeler [21][22][23] ile doldurmak enerji sönümleme kapasitesini arttırmaktadır. Hou ve arkadaşları [24] değişik hücre yapısına sahip enerji sönümleyicilerini farklı et kalınlık ve genişliğe göre modelleyerek en yüksek özgül enerji sönümleme kapasitesi ile ezilme kuvveti verimini elde edebilmek amacıyla optimizasyon çalışması gerçekleştirmişlerdir.…”

Section: Gi̇ri̇ş (Introduction)unclassified

Değişik geometrilere sahip enerji sönümleyici profillerin açılı yükler altında performanslarının incelenmesi

Altın¹

2018

Crashworthiness comparison of different configuration circular profiles Different deformation angles  Crush force efficiency and specific energy absorptionIn the scope of the study, ten energy absorber designs with different geometrical features with square and circular cross sections were designed and energy absorbing performances under different oblique loads were investigated by the finite elements method. Energy absorbing profiles were deformed by a rigid plate with 0°, 15° and 30° angles along 120 mm. The specific energy absorption and crush force efficiency values for each energy absorbing profile were investigated by the analyzes made. According to the results obtained, it is determined that the circular-section energy absorbers provide higher performance in all cases. Figure A. (a) Sectional view of finite element model for energy absorbing profile under oblique loading (b) top views of energy absorbing profilesPurpose: This paper presents a numerical study, where explicit dynamic finite element analysis (FEA) are performed by using LS-DYNA to simulate the crashworthiness performance of energy absorbing profiles (Figure A) under oblique (0°, 15° and 30°) impact loading. Theory and Methods:The crashworthiness responses of energy absorbing profiles under oblique loading are analyzed using the nonlinear explicit FEA software LS-DYNA. The material model used is "MAT_24_PIECEWISE_LINEAR_PLASTICITY" and the columns are modeled with four-noded shell elements using Belytschko-Tsay element formulation with five integration points through the thickness. After convergence, an element size of 2 mm was found to produce suitable results. The energy absorbing profile material was 6063, which is widely used in the automobile industry owing to its lightweight and energy absorbing capacity. The moving plate is assigned a downward velocity of 2 mm/ms to crush the profiles over the fixed plate. Results:Crush force efficiency and specific energy absorption capacity have changed for each profile as the deformation angle changes. The crashworthiness performance of the DT4 profile has the best specific energy absorption capacity (33,03 kj/kg) and crush force efficiency (% 85) under oblique loading. Conclusion:The different oblique loading conditions in terms of loading angle have significant effects on SEA and CFE. The deformation mode seems to depend on both load angle.