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1.
为实现某新车型车身快速验证其碰撞性能以及后续优化其碰撞性能,通过SFE参数化模型数据库搭建了该车型的碰撞车身模型,再结合Isight DOE实验方法进行早期碰撞性能预研。研究结果表明:利用该方法能够很好地满足工程设计要求,且能够大幅缩短车身开发设计周期和降低开发成本。  相似文献   
2.
Crashworthiness simulation system is one of the key computer-aided engineering (CAE) tools for the automobile industry and implies two potential conflicting requirements: accuracy and efficiency. A parallel crashworthiness simulation system based on graphics processing unit (GPU) architecture and the explicit finite element (FE) method is developed in this work. Implementation details with compute unified device architecture (CUDA) are considered. The entire parallel simulation system involves a parallel hierarchy-territory contact-searching algorithm (HITA) and a parallel penalty contact force calculation algorithm. Three basic GPU-based parallel strategies are suggested to meet the natural parallelism of the explicit FE algorithm. Two free GPU-based numerical calculation libraries, cuBLAS and Thrust, are introduced to decrease the difficulty of programming. Furthermore, a mixed array and a thread map to element strategy are proposed to improve the performance of the test pairs searching. The outer loop of the nested loop through the mixed array is unrolled to realize parallel searching. An efficient storage strategy based on data sorting is presented to realize data transfer between different hierarchies with coalesced access during the contact pairs searching. A thread map to element pattern is implemented to calculate the penetrations and the penetration forces; a double float atomic operation is used to scatter contact forces. The simulation results of the three different models based on the Intel Core i7-930 and the NVIDIA GeForce GTX 580 demonstrate the precision and efficiency of this developed parallel crashworthiness simulation system.  相似文献   
3.
This paper presents an investigation on the structural behavior of flattened expanded metal tubes subjected to axial crushing. At first, the study is carried out experimentally to investigate the effect of the angle formed between the expanded metal cell and the applied load. Secondly, the results are compared with experimental results for standard expanded metal sheets. Thereafter, numerical analyses are conducted by means of nonlinear finite element models, to investigate the enhancement in the energy absorption characteristics due to flattening of the expanded metal. Both results, experimental and numerical show a significant increase in energy absorbing capacity and mean force for the flattened tubes.  相似文献   
4.
Foam-filled thin-walled structure and multi-cell thin-walled structure both have recently gained attentions for their excellent energy absorption capacity. As an integrator of the above two kinds of thin-walled structures, foam-filled multi-cell thin-walled structure (FMTS) may have extremely excellent energy absorption capacity. This paper firstly investigates the energy absorption characteristics of FMTSs by nonlinear finite element analysis through LS-DYNA. Based on the numerical results, it can be found that the FMTS with nine cells has the most excellent crashworthiness characteristics in our considered cases. Thus, the FMTSs with cell number n=9 are then optimized by adopting a multi-objective particle swarm optimization (MOPSO) algorithm to achieve maximum specific energy absorption (SEA) capacity and minimum peak crushing force (PCF). During the process of multi-objective optimization design (MOD), four kinds of commonly used metamodels, namely polynomial response surface (PRS), radial basis function (RBF), Kriging (KRG) and support vector regression (SVR) for SEA and PCF, are established to reduce the computational cost of crash simulations by the finite element method. In order to choose the best metamodel for optimization, the accuracies of these four kinds of metamodels are compared by employing the error evaluation indicators of the relative error (RE) and the root mean square error (RMSE). The optimal design of FMTSs with nine cells is an extremely excellent energy absorber and can be used in the future vehicle body.  相似文献   
5.
单胞及多胞铝合金薄壁梁吸能特性研究   总被引:1,自引:0,他引:1  
对单胞、方孔多胞及蜂窝多胞三种薄壁梁进行了不同碰撞形式的仿真计算;利用台车碰撞试验台对蜂窝铝与方管铝薄壁梁结构的变形模式和变形量进行分析。结果显示,在相同的初始碰撞动能情况下,方孔多胞结构的压溃量最小,且以叠缩压溃的稳定变形模式进行;而在压溃量相同时,方孔多胞结构的吸能量最大,碰撞过程的材料利用率最高,其碰撞力峰值与均值差别最小。因此,方孔多胞薄壁梁应用于车身结构可以显著提高车辆的耐撞性能。  相似文献   
6.
PurposeThis study investigated the change in the fatality and severe injury risks in rear impacts with vehicle model years (MY) grouped prior to, during the phase-in and after the revision to FMVSS 301.MethodsFARS and NASS-CDS data were used to determine the injury risks of non-ejected occupants in light vehicles involving non-rollover, rear impacts. The data were analyzed by MY groups: 1996–2001, 2002–2007 and 2008+ to represent the years prior to, during the phase-in and post-revision phase-in of FMVSS 301. The 1996–2013 FARS data were analyzed for rear crashes defined by the initial crash direction (IMPACT1) and direction with most damage (IMPACT2) to the rear. Fatality risk was determined by the number of fatally injured occupants per all occupants with known injury status.The 1994–2013 NASS-CDS was analyzed for rear crashes defined by the damage area variable. The risk of severe injury (MAIS 4+F) was determined as the number of occupants with MAIS 4+F injury per all occupants with known injury status. The distribution of rear crashes was determined by impact location and crash severity. NASS-CDS electronic cases with 2008+ MY vehicles were analyzed to evaluate the vehicle and occupant performance.ResultsThe fatality risk was 20.6% in the 1996–2001, 17.3% in the 2002–2007 and 15.0% in the 2008+ MY vehicles using FARS with the initial crash direction variable (IMPACT1) to the rear. There was a 27.1% reduction in risk with post-FMVSS 301 vehicles 2008+ MY. The risk was 19.0%, 15.4% and 12.8% with the most damage variable (IMPACT2) to the rear. There was 32.8% reduction in risk with 2008+ MY vehicles.The NASS-CDS analysis showed that the risk of severe injury (MAIS 4+F) was 0.27 ± 0.05% for 1996–2001, 0.30 ± 0.13% for 2002–2007 and 0.08 ± 0.04% for 2008+ MY year vehicles. There was a 70.2% reduction in the risk for severe injury with 2008+ MY vehicles.The NASS-CDS case review of MAIS 4+F injury in rear impacts of 2008+ MY vehicles that comply with the revised FMVSS 301 indicated that the crashes were very severe and generally involved significant 2nd row intrusion.ConclusionsThe revision to FMVSS 301 has effectively reduced the risks for fatal and severe injury in vehicles compliant with the revision (2008+ MY). The reduction was 27.1–32.8% in fatality risk using FARS data and 70.2% in severe injury risk using the NASS-CDS when compared to vehicles prior to the phase-in of the revised FMVSS 301 (1996–2001 MY vehicles). It is not possible to parse the effects of other design changes in seats and restraint systems that also increased safety over the study years.  相似文献   
7.
为了提高轿车侧面耐撞性,设计耐撞性能强的B柱成为主要课题之一.目前的优化方法很难将B柱侵入量和侵入速度同时控制在理想范围内.因此,提出泡沫铝材料填充在汽车B柱内代替B柱加强板的方法,缓冲侧面碰撞冲击.通过建立泡沫铝有限元模型与材料特性分析,确定仿真泡沫铝主要材料参数.进而根据中国新车评价规程C-NCAP要求,建立轿车整车侧面碰撞有限元模型,采用LS-DYNA软件进行仿真分析.结果表明,泡沫铝填充后的B柱侵入量和侵入速度都有明显降低.泡沫铝材料塑性变形和整体弯曲变形能够吸收1.51kJ的能量,是B柱加强板的3倍.填充泡沫铝前后仿真结果表明,轿车B柱填充泡沫铝是一种提高轿车侧面耐撞性的方法.  相似文献   
8.
For the classic thin-walled energy absorber, the energy dissipation during a collision is concentrated over relatively narrow zones. This means that a great deal of materials of the columns do not participate in the plastic deformation or not enter into the large plastic deformation stage. To expand the plastic deformation zones and improve the energy absorption efficiency, a new type of kagome honeycomb sandwich bitubal circular column is presented in this paper. This innovative impact energy absorber is made of two circular aluminum tubes filled with core shaped as a large-cell kagome lattice. The interaction effect, deformation mode and energy absorption characteristics of the composite structure are investigated numerically. Observing the collapsing process, it is found that the kagome lattices buckle first, which triggers the outer and inner skin tubes to fold locally. This behavior increases the plastic deformation areas. Moreover, the presence of the outer and inner tubes strengthens the buckling capacity of kagome cell. Furthermore, the folded tube walls intrude into the gap of the honeycomb cell, which further retards the collapse of the honeycomb cell. So the interaction effects between the honeycomb and column walls greatly improve the energy absorption efficiency. In addition, the effects of geometrical parameters of the kagome honeycomb on the structural crashworthiness are studied. It is found that the cell wall thickness and cell distribution (cell number in the circumferential direction) have distinct effects on the specific energy absorption. Besides, we also studied the foam-filled column with the same foam density as the kagome honeycomb and compared it with the kagome sandwich structure. It is found that the kagome sandwich column has higher mean crash force and better energy absorption characteristics.  相似文献   
9.
武装直升机抗坠毁设计研究   总被引:5,自引:0,他引:5  
介绍了武装直升机抗坠毁的概念设计原理 ,提出了抗坠毁设计中的一些关键问题 ,为武装直升机抗坠毁设计提供理论指导。  相似文献   
10.
In the paper, crashworthiness of the S-shaped rail extracted from the frontal frame in a car is studied. In order to reduce the peak impact force while increasing the total absorbed energy, the hybrid materials are employed in that rail, where aluminum alloy is used for its front part and advanced high strength steel (AHSS) for its back part. By designing 16 experiments based on orthogonal experiment, the effect of five influence factors with four levels on the crash performance of the steel–aluminum hybrid S-shaped front rail is emphatically investigated. These influence factors include the different material types of aluminum alloy and AHSS, the sheet thicknesses of the two parts, and length proportion for the aluminum part. The AHSS includes dual-phase (DP) steel, transformation induced plasticity (Trip) steel and Mart steel; the aluminum alloy series include 5000 and 6000 series. The research result shows that the use of steel–aluminum hybrid materials can reduce the peak impact force and the total weight for the S-shaped front rail, while the total absorbed energy can be greatly increased, so the crashworthiness and lightweight of the S-shaped front rail are significantly improved.  相似文献   
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