The antiwear and antifriction coating, which contains TiB2 and Nickel-coated graphite, has been obtained on stainless steel 9Cr18 by laser cladding. The processing method, microstructure, interface, microhardness, tri...The antiwear and antifriction coating, which contains TiB2 and Nickel-coated graphite, has been obtained on stainless steel 9Cr18 by laser cladding. The processing method, microstructure, interface, microhardness, tribological properties and the forming mechanisms of the coating are analyzed. Results show that the microstructure of the clad coating are mainly long plume-like primary phase sosoloid Ni-Fe which form the matrix framework, while the in-situ anomalous synthetical TiC grains and uhrafine TiB2 grains uniformly disperse among the framework. The hardness and wear resistance of the coating has been greatly improved, which can be attributed to the reinforcement mechanism of TiC, TiB2, FeC, Fe3C and Cr23 C6. etc. At the same time, the coating has friction-reducing ability.展开更多
选择了配备有P1和P3的双电机插电式混合动力汽车(plug-in hybrid electric vehicle,PHEV)作为研究平台。在能量回收过程中,P1和P3电机可以同时进行,相比其他构型而言有着更加明显的能量回收优势。车辆制动过程中,当P1电机效率高于P3时,...选择了配备有P1和P3的双电机插电式混合动力汽车(plug-in hybrid electric vehicle,PHEV)作为研究平台。在能量回收过程中,P1和P3电机可以同时进行,相比其他构型而言有着更加明显的能量回收优势。车辆制动过程中,当P1电机效率高于P3时,优先选用P1电机进行制动,P3电机提供剩余所需制动力;当P3电机效率高于或等于P1时,则优先选用P3电机进行制动,P1电机弥补剩余所需的制动力。以搭载AMT(电控机械制动变速箱)的双电机插电式混合动力汽车为研究对象,在保证制动安全性的前提下,为尽可能地回收能量,提出一种基于双电机能量回收的前后轴制动力分配、机电制动力分配以及双电机制动力分配的多级制动力分配策略。结合Matlab/Simulink搭建整车模型,并进行仿真分析。仿真结果显示,制动能量回收率最高能达到66.56%,回收效果良好。展开更多
在工程问题中,尽管积累了大量的实验、仿真和设计经验,传统的设计方法仍然面临着知识利用率不高的挑战。为了有效利用知识信息来加速装备的设计与开发,一种基于知识挖掘的高维模型表示(High dimensional model representation,HDMR)优...在工程问题中,尽管积累了大量的实验、仿真和设计经验,传统的设计方法仍然面临着知识利用率不高的挑战。为了有效利用知识信息来加速装备的设计与开发,一种基于知识挖掘的高维模型表示(High dimensional model representation,HDMR)优化方法被提出。首先,引入了一种改进的多元模型筛选策略,以提高HDMR子项的构建效率和预测精度。之后,提出了一种基于知识挖掘的优化策略。该策略使用全局代理模型替代真实函数,以最优样本为中心点构建HDMR子项,并在每个子项代表的维度上分别寻找局部最优点,并通过置信度对比挖掘全局潜在较优点,以加速算法寻优。最终,利用该方法开展翼身融合水下翔机(Blended-wing-body underwater glider,BWBUG)外形优化设计。在满足体积约束的条件下,将滑翔机的升阻比提升了5.04%,优于无知识辅助下升阻比提升2.93%的优化结果,验证了所提方法中知识挖掘的作用。展开更多
文摘The antiwear and antifriction coating, which contains TiB2 and Nickel-coated graphite, has been obtained on stainless steel 9Cr18 by laser cladding. The processing method, microstructure, interface, microhardness, tribological properties and the forming mechanisms of the coating are analyzed. Results show that the microstructure of the clad coating are mainly long plume-like primary phase sosoloid Ni-Fe which form the matrix framework, while the in-situ anomalous synthetical TiC grains and uhrafine TiB2 grains uniformly disperse among the framework. The hardness and wear resistance of the coating has been greatly improved, which can be attributed to the reinforcement mechanism of TiC, TiB2, FeC, Fe3C and Cr23 C6. etc. At the same time, the coating has friction-reducing ability.
文摘选择了配备有P1和P3的双电机插电式混合动力汽车(plug-in hybrid electric vehicle,PHEV)作为研究平台。在能量回收过程中,P1和P3电机可以同时进行,相比其他构型而言有着更加明显的能量回收优势。车辆制动过程中,当P1电机效率高于P3时,优先选用P1电机进行制动,P3电机提供剩余所需制动力;当P3电机效率高于或等于P1时,则优先选用P3电机进行制动,P1电机弥补剩余所需的制动力。以搭载AMT(电控机械制动变速箱)的双电机插电式混合动力汽车为研究对象,在保证制动安全性的前提下,为尽可能地回收能量,提出一种基于双电机能量回收的前后轴制动力分配、机电制动力分配以及双电机制动力分配的多级制动力分配策略。结合Matlab/Simulink搭建整车模型,并进行仿真分析。仿真结果显示,制动能量回收率最高能达到66.56%,回收效果良好。
