新型点阵夹层防撞梁与负泊松比吸能盒复合总成开发与吸能性能

为高效解决车身结构抗撞性和轻量化同步实现的难题，以乘用车前防撞梁与吸能盒为例，将点阵夹层结构与负泊松比结构用于其设计，并考察新型复合总成的吸能性能。以传统高强钢方案作为对标基准，获取待开发总成的性能设计依据。基于高强钢总成40%重合率碰撞试验，完成有限元模型的精度验证，进而获得全宽碰撞的结构响应特征及吸能参考数值，用于指导新型总成的开发。通过数值模拟算例，分析新型复合总成对冲击输入能量的适应性及吸能量对负泊松比吸能盒壁厚的敏感性，从而提出增加吸能盒封板与防撞梁支撑的改进方案。改进后的点阵夹层防撞梁具有更佳的承载刚度与载荷传递能力，总成变形模式愈加合理；改进前、改进方案1与改进方案2的总成吸能量分别占输入总能量的11.5%、68.2%与92.76%，高于高强钢方案的64.09%；改进方案2较高强钢方案减重32.9%。复合前防撞总成的台车试验与仿真结果对比显示：输入能量、碰撞初速度、总成吸能量、平均压溃量、平均碰撞力与回弹速度等指标的偏差绝对值均小于5%。结果表明：采用点阵夹层结构与负泊松比结构后，新型复合总成的吸能性能与轻量化水平均优于高强钢方案，2类结构适合于车辆承载与吸能结构，复合总成的设计方法与开发流程适用于相关新型结构的开发。

Development and Energy-absorption Performance of a Novel Composite Assembly Consisting of a Lattice Sandwich Anti-collision Beam and Crash Box with Negative Poisson's Ratio

In order to efficiently and simultaneously solve the problems of realization of crashworthiness and lightweight car body structure, the lattice sandwich structure and negative Poisson's ratio structure were used in the design of the front crash beam and energy absorption box for passenger cars. In addition, the energy absorption performance of the new composite assembly was investigated. Using the traditional high-strength steel scheme as a benchmark, the performance design basis for the assembly to be developed was obtained. Based on a high-strength steel assembly collision test with a 40% coincidence rate, the accuracy of the finite element model was verified. The structural response characteristics and energy absorption reference values of full-width collisions were obtained, which can be used to guide the development of new assemblies. The adaptability of the new composite assembly to input energy from impact was analyzed using numerical simulation, as well as the sensitivity of energy absorption to the wall thickness of the negative Poisson's ratio energy absorption box. Subsequently, an improvement scheme for adding an energy absorption box sealing plate and an anti-collision beam support was proposed. The improved lattice sandwich anti-collision beam has better bearing stiffness and load transfer capacity, and the deformation mode of the assembly is more reasonable. The energy absorption of the assembly before improvement, with improvement scheme 1, and with improvement scheme 2 accounts for 11.5%, 68.2%, and 92.76% of the total input energy, respectively. This result is higher than the 64.09% resulting from the high-strength steel scheme. Compared with the high-strength steel scheme, the improved scheme 2 reduces the weight by 32.9%. A comparison between the trolley test and the simulation results of the composite front anti-collision assembly shows that the absolute deviation of the input energy, initial collision speed, energy absorption of the assembly, average crushing amount, average collision force, and rebound speed are all less than 5%. The results show that the energy absorption performance and lightweight level of the new composite assembly are better than those of high-strength steel after adopting the lattice sandwich structure and negative Poisson's ratio structure. These two types of structures are suitable for load-bearing vehicles and energy-absorbing structures. The design method and development process of the composite assembly are suitable for the development of related new structural assemblies.