The aging process of a proton exchange membrane fuel cell(PEMFC)affects its output performance,and in order to accurately control output power,it is necessary to consider the aging and power degradation trends of the PEMFC.In this paper,the power-current curve is used as an indicator of the state of health(SOH).Based on previous studies,improvements have been made by considering changes in open-circuit voltage during the aging process.The number of aging factors in the aging model has been increased and the mapping relationship between the PEMFC power and the aging of the internal components is established.A semi-mechanical power degradation model is derived based on polarization curves,and an aging rate model has been designed using the particle filter algorithm.Combining the power decay analysis,the paper estimated the fuel cell's SOH.Simulations were carried out on the test dataset and compared with experimental test data.The results show that the method can predict the long-term performance decay model.Furthermore,compared with existing research methods,the proposed method estimates the SOH and performance decay trend of PEMFCs more accurately through the use of aging rate reference values and the power decay model.With reduced training time,there is an improvement in estimation accuracy.Especially when the training time is 100 hours and the estimation time is 250 hours,the error's relative decrease rate reaches 65.69%.
Numerical study on impact damage characteristics of automotive coatings is significant for the material development and structural design of the coatings. A finite element model is proposed for the single-impact damage of automotive coatings, and an in-house explicit finite element program is used to solve the impact problem. The predicted polymer-ply failure patterns and coating delamination area radius are in good agreement with the experimental outcomes, which verifies the capacity of the proposed method in the impact damage analysis of automotive coatings.
针对目前儿童座椅常存在因结构设计不合理而导致的保护效果差的问题,基于MADYMO建立了包含台车座椅、某款典型儿童座椅、五点式安全带、P3儿童假人的儿童约束系统模型,根据GB 27887标准进行正面碰撞台车试验,基于试验结果从假人运动轨迹和损伤指标两方面对模型进行了验证.结果表明,建立的儿童约束系统模型能较真实地反映实车碰撞过程,具有较高的准确性.在模型验证的基础上,针对碰撞中座椅上部存在变形量过大的问题,提出了在椅背顶部后侧加装加强板,并将椅背与椅盆连接处位置原有的凹槽贯通的改进方案,对改进后的儿童座椅进行了不同加速度下正面碰撞工况的仿真分析和安全性评估.结果表明,改进方案能在座椅质量不增加的前提下,有效减少椅背的变形量,确保碰撞中座椅结构的完整性和儿童的安全,达到了预期的防护效果.研究结果可为儿童座椅的设计和改进提供支撑和参考.
为了从海量自然驾驶数据中有效提取典型驾驶场景,提出一种基于驾驶行为基元的典型驾驶场景识别与提取方法,搭建了具有多类场景覆盖及通用程度高的典型驾驶场景自动化识别与提取框架,解决了当前方法仅适用特定单一场景提取,无法从大规模数据中高效提取场景的问题.
车辆的振动舒适性不仅影响乘客的乘坐体验,对于雷达车等装载精密设备的特种车辆而言,车辆的振动噪声还会影响雷达的正常工作或降低指挥官间的沟通质量.车身附加结构阻尼是改善车辆乘坐舒适性的一种有效措施,以某类雷达车车身地板为研究对象,详细研究了附加结构阻尼层的布置优化方法,认为拓扑优化设计方法是附加结构阻尼层优化布置的有效方法.在此基础上进一步研究了附加自由阻尼层的局部约束化优化方法,探讨了局部约束化对自由阻尼层性能的影响.
