FDS技术在钢铝混合车身上的应用

随着汽车轻量化的发展,新材料、新工艺不断被应用,高强钢、铝合金、镁合金及碳纤维等轻质材料应用比例越来越高。多元化的材料对连接工艺和技术也带来了新的挑战,传统的电阻点焊已不再适用,包括流钻螺钉(FDS)、自冲铆接、铝点焊、结构胶等连接新工艺逐渐被主机长广泛应用。文章基于某款钢铝混合的轻量化新能源车型,介绍了铝合金减震器塔与钢制车身的流钻螺钉FDS连接设计与应用,希望能给同行以参考。     

基于铝合金减振器塔的白车身模态分析与研究

为了确保白车身模态性能在设计阶段满足要求,在设计前期需要对白车身模态进行分析研究。论文首先利用有限元分析软件对搭载铝合金减振器塔的某钢铝混合白车身设计模型的模态进行仿真分析和摸底,再通过试验测试方法对实车的模态进行分析确认,两种方法相辅相成,为后期的产品优化提供有效数据支撑。结果表明:有限元分析结果精度高(有限元分析结果与试验测试结果基本相当,误差在2%左右),有限元分析软件强大的模拟计算能力使大量繁琐的工程问题简单化,可以节省大量的开发时间和成本;同时再结合试验测试对有限元分析结果进行校核修正,两种方法相结合可以为汽车设计方案的设计和优化提供行之有效的解决方案。     

大功率牵引变流器电流谐波最小PWM控制策略的研究与实现

大功率交流传动机车牵引传动系统受器件开关频率的限制,在高速运行区需要采用同步优化调制的方法来减小谐波,针对电流谐波最小PWM调制技术,对其控制原理进行了理论分析,论述了一种基于数字信号处理器DSP的数字实现方法,研究了不同调制模式之间的波形切换原则及控制策略,在谐波抑制性能方面与SHEPWM调制算法进行了对比分析,最后通过仿真和实验对理论分析的正确性和有效性进行了验证。     

基于泊位数的公交站点优化研究

随着城市的不断发展，优化公交站点对于提高城市线路的通行能力至关重要。本文从公交站点泊位数出发，对石家庄保龙仓购物广场站点进行调查数据并进行分析，运用模型计算该站的泊位数和线路数，并提出相应改善建议和优化方案，为石家庄市公交站点优化提供一定的理论和技术支持。     

Finite Element Optimization of Vee-ring Factor in Fine-blanking Process

The vee-ring is one of the most characteristic features of the fine-blanking process which is derived from the conventional blanking. With the vee-ring, a counter plate and some other working parameters, a component with a precise geometry and smoothly blanked surface can be produced without any major secondary operations. However, these working parameters are always empirically determined or determined by trial-and-error method, which is time-consuming and expensive. In this study, a numerical simulation method was used to analyze the effect of vee-ring factors on product quality, such as distance between vee-ring and punch, vee-ring height and blank holder force, so as to obtain as high clean cut ratio as possible. During the simulation, the model was assumed as axisymmetric one and the workpiece was considered as rigid plastic material, meanwhile the tools were defined as rigid bodies so as to shorten the computational time. A damage model taking into account the influence of hydrostatic stress was used to simulate material fracture in fine-blanking. The result obtained from the simulation indicated that with the help of vee-ring, the metal material near the shear band does not flow with the punch penetration and high compressive stress in the shear band is generated. Consequently, higher clean cut ratio can be obtained with a vee-ring model than the one obtained with a plane blank holder model. Furthermore, the longer the distance between vee-ring and punch is, the higher the height of roll-over becomes.     

哥们儿一场

这就是我和老道、伟哥的西藏行。出行之初的生张儿,现在已经是哥们儿一场。 "首席技工"伟哥下定决心去西藏后,选择同行伙伴就成了头等大事。倒是有不少人愿意与我同行,我却未必能带,万里行程,绝不是闹着玩的,万一有个闪失,对谁都没法交代。这时候是需要一份清醒的理智的。缜密考虑,圈定人选,力诚相邀,没戏——都有事务缠身,就我不务正业似的。网上征招,又是个比较传统的人,觉得那也不靠谱,怕千山万水之外被放了鸽子。     

A new approach of intelligent design and optimization for shell nosing

Preform design for shell nosing product without machining the inner surface after forming is an experience-extensive work. Generally, the initial design needs to be modified and simulated consequently to get proper preform and nosing die, and the iterative process is time consuming. This paper puts forward a new approach, in which the suitable initial design can be obtained by knowledge-based intelligent technology and the optimal design can be acquired by finite element method (FEM) based geometrical modification. With the CAX object model as the bridge of CAD and CAE, the CAD model with simulation knowledge can be transferred into CAE automatically, and the CAE result can be automatically utilized as well. Based on the comparison between the simulated shape and the desired shape, the dissatisfactory area will be modified. A new simulation and modification process will be carried out based on the modified design. The process is repeated iteratively to get the optimal design. This approach utilizes the commercial CAD and CAE software, without the need of complex back-forward FEM procedures. Based on the new approach, an in-home intelligent shell nosing design and optimization system is developed, and a case study proves that this system can reach a reasonable design efficiently.