Değişik geometrilere sahip enerji sönümleyici profillerin açılı yükler altında performanslarının incelenmesi

Abstract

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.

A review of performance improvement approaches on crash boxes

“…İTK' nin artması, yüksek kuvvetin çarpışma kutusunun arkasındaki parçalara ve sürücüye yükün iletileceği anlamına gelir. Bu sebeple, çarpışma kutularında ÖEE değerinin olabildiği en yüksek değerlerde olması istenirken, İTK' nin minimumda tutulması hedeflenir [21,60]. ÖEE' den ödün verilecek olsa da zayıflatıcı ve çökmeyi kontrol edici bazı tasarımsal eklemelere ihtiyaç duyulur.…”

“…Bu değer, çarpışma kutusunun arkaya doğru ve yolcuya ne seviyelerde ve ne kadar dengeli kuvvet ilettiğinin bir göstergesidir. ÖEE ise bir çarpışma kutusunun sönümlediği enerji miktarının kütlesine oranıdır ve araçlarda hafifliğin önemini de dikkate alır [3, [21][22][23].…”