汽车前端薄壁结构斜向耐撞性研究与优化设计

发布时间：2018-04-27 12:41

本文选题：薄壁结构 + 耐撞性　；参考：《湖南大学》2016年硕士论文

【摘要】：安全性设计是现代汽车设计中的关键环节,如何提高汽车的耐撞性成为了研究的热点问题。薄壁吸能结构因其良好的能量吸收能力被广泛应用在汽车、船舶、轨道交通、航空航天等领域。对汽车车身上的薄壁结构进行耐撞性研究和优化设计,可以有效地提高汽车的耐撞性能。现实交通事故形式复杂,冲击载荷工况多种多样。薄壁管是汽车车身上最为典型的结构形式,其性能好坏显著影响着汽车的碰撞安全。前人对薄壁管的研究主要针对轴向压缩工况,但现实中汽车斜角碰撞的工况更为普遍,所以对薄壁管斜向冲击载荷作用下的耐撞性能研究具有重要意义。本文以薄壁管为研究对象,采用有限元数值仿真以及近似代理模型技术等设计方法作为研究手段,对影响薄壁管斜向冲击下吸能性能的相关结构和材料参数进行分析和优化设计。首先,通过参数分析研究薄壁管结构参数对斜向碰撞的性能表现的影响,为后续薄壁管斜向耐撞性设计提供参考。研究发现锥形薄壁管相较于一般薄壁直管具有更好的抗弯折能力,因此使用该种构型的薄壁管作为耐撞性设计初始结构。对泡沫铝填充的薄壁管进行耐撞性分析,比较密度以及填充方式对耐撞性的影响,提出了泡沫铝密度梯度填充的构型。对密度梯度填充型式的薄壁管进行碰撞仿真,发现其在轴向和斜向碰撞过程中均有良好的性能表现。进一步对多胞薄壁管进行耐撞性研究。研究表明多胞结构在轴向碰撞中变形模式较为稳定,本文对7种构型锥形多胞锥形薄壁管进行斜向耐撞性分析,选取吸能潜力最佳的结构,采用代理模型技术和诱导变形的方法,对锥形多胞结构进行参数优化设计,在兼顾轴向耐撞性的同时显著提升斜向耐撞性。根据美国正面30°斜角碰撞法规要求,对某款整车进行耐撞性分析。依据之前对薄壁结构斜向耐撞性的研究结论,对影响整车安全性能的关键部件进行结构改进,采用泡沫铝填充以及使用高强度钢的方法,较为明显地改善了整车在斜角碰撞时的性能表现。验证了本文的研究方法和结论具有一定的实际工程意义。
[Abstract]:Safety design is a key link in modern automobile design. How to improve the crashworthiness of vehicles has become a hot issue. Thin-walled energy absorption structures are widely used in automobile, ship, rail transit, aerospace and other fields because of their good energy absorption capacity. The crashworthiness research and optimization design of the thin-walled structure on the automobile body can effectively improve the crashworthiness of the vehicle. The real traffic accident forms are complex, the impact load condition is various. Thin-wall tube is the most typical structural form of automobile body, and its performance has a significant impact on vehicle collision safety. Previous researches on thin-walled tubes are mainly aimed at axial compression conditions, but in reality the oblique impact conditions are more common, so it is of great significance to study the crashworthiness of thin-walled tubes under oblique impact loads. In this paper, the thin-walled tube is used as the research object, the finite element numerical simulation and the approximate agent model technology are used as the research means. The related structure and material parameters which affect the energy absorption performance of thin wall tube under oblique impact are analyzed and optimized. Firstly, the influence of structural parameters on the performance of oblique impact of thin-walled tubes is studied by parameter analysis, which provides a reference for the design of oblique crashworthiness of thin-walled tubes. It is found that the conical thin-walled tube has better bending resistance than that of the general thin-walled tube. Therefore, the thin-walled tube with this configuration is used as the initial crashworthiness design structure. The crashworthiness analysis of thin-walled tubes filled with aluminum foam was carried out, and the effects of density and filling mode on the crashworthiness were compared, and the configuration of density gradient filling of aluminum foam was put forward. The impact simulation of thin-walled tube filled with density gradient is carried out, and it is found that it has good performance in the process of axial and oblique impact. Furthermore, the crashworthiness of polycellular thin-walled tubes was studied. The results show that the deformation mode of polycell structure is stable in axial impact. In this paper, the oblique crashworthiness analysis of seven kinds of conical conical thin-walled tubes is carried out, and the structure with the best energy absorption potential is selected. The method of agent model and induced deformation is used to optimize the parameters of the conical polycell structure, which can significantly improve the oblique crashworthiness as well as the axial crashworthiness. According to the American law of 30 掳angle collision, the crashworthiness of a vehicle is analyzed. Based on the previous research results on the oblique crashworthiness of thin-walled structures, the structural improvement of the key components affecting the safety performance of the whole vehicle is carried out, and the method of filling with aluminum foam and using high strength steel is adopted. It obviously improves the performance of the whole vehicle during the oblique impact. It is verified that the research method and conclusion of this paper have some practical engineering significance.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.82

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