产品跌落冲击耐撞性能稳健设计研究进展

跌落冲击是物体在短时间内受到强大冲击力而运动状态发生急剧变化的现象,是导致产品特别是小型机电产品外表破损、功能失效的主要原因。近年来,国内外研究学者针对如何提高产品抗跌落冲击的本质耐撞性能进行了大量研究。笔者从研究对象、研究方法等角度,系统总结了产品跌落冲击耐撞性和产品耐撞性能稳健设计的研究现状,归纳了有待进一步研究的问题。     

响应表面法在薄壁构件耐撞性优化设计中的应用研究

汽车结构的耐撞性及碰撞吸能优化是现代汽车工业重要的研究内容。耐撞性的优化涉及材料与结构的众多参数。传统的设计、碰撞仿真及试验往往只能在一定程度上改善结构的碰撞性能而无法达到限定条件下的最优状态。利用国际上近年来新发展起来的一种优化理论方法--响应表面法,结合传统的优化手段以及非线性有限元程序对薄壁构件的耐撞性问题进行了优化研究。耐撞性优化的结果表明,该方法具有较高的精确性和有效性。     

A型不锈钢地铁车体耐撞性研究

轨道车辆车体基本性能的研究需要考虑多方面的因素,车体耐碰撞性是重要指标之一。以A型不锈钢地铁车体为研究对象,基于LS-DYNA碰撞仿真平台,分析了车辆在不同碰撞速度下车体的耐撞性能;然后,采用逼近法,获取了该型地铁车的最大碰撞安全速度,为车体的耐撞性设计提供了理论支撑。     

飞行器机身结构耐撞性分析与设计

耐撞性不仅是飞行器设计中的重要问题,而且还是其取得适航证的必要条件。该文对美国、欧盟和日本等在耐撞性研究方面的研究进行了总结,阐述了耐撞性设计中采用的数值模拟和试验研究方法及其主要问题。主要针对各种飞行器结构耐撞性设计方法进行介绍,对比了轻型固定翼飞机、直升机和大中型民用飞机的耐撞性设计特点。能量吸收结构是耐撞性设计的关键问题之一,对提高飞行器机身能量吸收能力的机身底部结构、机身加强框和客舱地板撑杆结构等设计方法进行详细介绍,总结了飞行器耐撞性可靠性分析和优化设计方法。最后对飞行器结构耐撞性设计的发展作了展望。     

基于LS-DYNA的移动硬盘跌落冲击耐撞性能分析

移动硬盘独特的机械工作方式和部件结构的复杂性决定其对振动冲击非常敏感。针对移动硬盘复杂的内部结构,遵循质量等效原则,基于ANSYS/LS-DYNA动力学分析软件建立非工作状态下的移动硬盘整体跌落冲击有限元模型,分析并确定移动硬盘跌落冲击耐撞性能评价指标。通过数值仿真,分析传动臂材料、传动臂形状以及跌落角度对移动硬盘耐撞性能的影响,为移动硬盘的耐撞性分析、评估与设计提供理论依据。     

复合材料加筋壁板鸟撞动响应分析

考虑复合材料蜂窝夹芯结构的冲击损伤,采用接触碰撞耦合方法研究了复合材料加筋壁板的抗鸟撞性能。鸟撞方式包括垂直冲击和斜冲击两种,复合材料的冲击损伤模型采用Chang-Chang模型,分析了三种鸟撞速度下鸟撞性能参数如复合材料壁板的失效单元数、鸟体剩余动能和筋条的变形,以及复合材料壁板和筋条在某一鸟撞速度下应力随筋条数的变化规律。计算结果表明：垂直冲击和斜冲击下复合材料加筋壁板的抗鸟撞性能不同,并非筋条越多越有利于改善抗鸟撞性能,筋条有时还可能起反作用。     

浅谈汽车前纵梁耐撞性结构改进

文章主要进行了汽车结构耐撞性研究,分析客车特别是轿车和微型客车的车身结构对碰撞能量的吸收特性,寻求改善车身结构耐撞性的方法,使得车身结构在外力冲击下能以预计的方式变形,其变形量能控制在一定的范围内,在保证乘员安全空间的前提下,车身变形吸收的能量最大,从而使传递给车内乘员的碰撞能量降低到最小,尽可能使乘员所受的加速度最小。     

基于拓扑优化与诱导结构的抗撞结构优化设计EI北大核心CSCD

鉴于耐撞性拓扑方法在实际使用中只能获得抗撞结构的初级拓扑构型,导致抗撞结构的碰撞安全性仍有进一步提升空间的问题,以耐撞性拓扑优化为基础,获得了抗撞结构的初级拓扑构型,在初级拓扑构型的适当位置设置诱导结构,得到最终吸能单元构型,再利用稳健性设计方法获取最终构型的最优尺寸参数,较好地弥补了基于最大吸能原则的耐撞性拓扑方法的不足。算例表明,所提的优化设计方法灵活有效,基于该方法得到的抗撞结构可以更好地满足设计要求。     

泡沫填充多边形单锥管与双锥管斜向加载下耐撞性分析

锥形泡沫填充结构结合了泡沫填充结构与锥形结构的优势,具有优异的吸能性和抵抗失稳变形的能力。研究了具有不同横截面的泡沫填充多边形单锥管(FSPTTs)与泡沫填充多边形双锥管(FBPTTs)在四种冲击角度下的耐撞性。采用多准则评估方法(COPRAS)对不同横截面的泡沫填充单锥管与泡沫填充双锥管的综合耐撞性进行了评估。评估表明:综合考虑多种冲击角度时,圆形截面泡沫填充单锥管较其他截面泡沫填充单锥管具有更好的耐撞性;圆形截面泡沫填充双锥管较其他截面泡沫填充双锥管具有更好的耐撞性。最后,针对圆形截面泡沫填充单锥管与圆形截面泡沫填充双锥管,以最大比吸能和最小峰值力为目标,采用非支配遗传算法对这两种结构在四种冲击角度下进行了多目标优化。结果表明:当冲击角度从0°变化到10°时,两种结构的Pareto曲线变化不大,而当冲击角度从10°变化到30°时,冲击角度对Pareto曲线形状和位置有显著影响;在冲击角度为0°和10°时,圆形截面泡沫填充双锥管的耐撞性优于圆形截面泡沫填充单锥管,而在冲击角度为20°和30°时,圆形截面泡沫填充单锥管的耐撞性优于圆形截面泡沫填充双锥管。实际应用中,可以根据工程需要选择合适的结构。     

汽车车身耐撞性设计参数的区间稳健性优化

基于区间分析,提出了一种考虑公差的汽车车身耐撞性稳健优化设计模型,可在有效降低耐撞性能对设计参数波动敏感性的同时实现公差范围的最大化。该模型首先利用对称公差来描述汽车碰撞模型中车身关键耐撞部件的主要尺寸、位置和形状等设计参数本身的不确定性,然后将参数设计和公差设计相结合,建立了以稳健性评价指标和公差评价指标为优化目标,设计变量名义值和公差同步优化的多目标优化模型。再次,利用区间可能度处理不确定约束,将该优化模型转换为确定性多目标优化模型。最后,将该模型应用于两个汽车耐撞性优化设计问题,并通过序列二次规划法和改进的非支配排序遗传算法进行求解,结果表明该方法及稳健优化设计模型可行且实用。     

Multiobjective optimization of multi-cell sections for the crashworthiness design

Plastic deformation of structures absorbs substantial kinetic energy when impact occurs. For this reason, energy-absorbing components have been extensively used in the structural design of vehicles to intentionally absorb a large portion of crash energy to reduce the severe injury of occupants. On the other hand, high peak crushing force may to a certain extent indicate the risk of structural integrity and biomechanical damage of occupants. For this reason, it is of great significance to maximize the energy absorption and minimize the peak force by seeking for optimal design of these components. This paper aims to design the multi-cell cross-sectional thin-walled columns with these two crashworthiness criteria. An explicit finite element analysis (FEA) is used to derive higher-order response surfaces for these two objectives. Both the single-objective and multi-objective optimizations are performed for the single, double, triple and quadruple cell sectional columns under longitudinal impact loading. A comparative analysis is consequently given to explore the relationship between these two design criteria with the different optimization formulations.     

Reliability-enabled changes in the design and manufacture of commercial electronic products

It has now become possible to design electronic products that have only a small probability of failing in a period of technologically useful life, if these products are to be used in an environment controlled for human comfort. Such product designs, even ones containing considerable complexity, can use combinations of ASIC and semi-custom VLSI devices, damage-resistant packaging and fault-tolerant techniques to achieve breakthrough reliability. The theme of this paper is that once field failures can be reduced to small fractions of the units produced, by means of such design approaches, then major changes and their accompanying cost savings become possible in the manufacture and support of these electronic products. Although some extra design validation steps will be needed, the resulting opportunities can be very significant for companies that design and manufacture electronic products. This reliability-enabled strategy is fully described in this paper.     

Optimizing the design and impact behavior of a polymeric enclosure

This paper focuses on the application of finite element analysis to design an electronic enclosure with improved impact resistance properties. With the growing push towards miniaturization there is a constant decrease in the wall thickness of the enclosure applications. This necessitates use of ribs to enhance the impact resistance. This study aims at investigating optimal design of ribs for improving impact resistance. The ‘DSGZ’ phenomenological constitutive model, which uniformly describes the entire range of stress–strain constitutive relationship of polymers under any monotonic loading mode is used to predict the plastic failure energies. Several simulation runs were performed based on the design parameters using a 2³ factorial design of experiments. The results from these simulations were used to analyze and study the various design parameters and its influence on the impact energy. It was found that when designing enclosures with ribs with an objective to maximize the impact failure energy, stress should be laid on optimizing the ratio of wall thickness to rib height within permissible limits while center-to-center spacing between the ribs and rib thickness do not have a significant effect.     

舰载电子设备抗冲击设计概要

舰载电子设备是舰船信息化建设的基础,在实际工作环境中,不可避免地会受到水下爆炸冲击作用,如果结构设计不当,将使其受到损害以至失效。从舰船冲击环境和电子设备的抗冲击要求出发,概要性地提出舰载电子设备抗冲击设计的基本原则,指出在电子机柜设计、冲击下工程材料的动态特性及采用隔振器进行抗冲击防护设计三方面的要点,并对采用冲击试验机对舰载电子设备抗冲击能力进行考核时冲击试验机的选择和相关冲击标准进行介绍。     

高性能零件的性能与几何参数一体化 精密加工方法与技术

随着高端装备和产品的不断发展,对装备和产品制造的性能要求也越来越多和越来越高,涌现出一大批高性能指标要求的关键零部件,其加工已由以往的单纯几何形状和尺寸精度要求,跃升为以性能要求为主、性能与几何参数一体化的精密加工要求。这些高性能零件多呈精密复杂曲面、超高精度,以及材料超硬、超脆、超黏等难加工特征,其性能受几何、材料等多因素耦合作用,采用传统工艺进行精密加工制造十分困难,存在废品率高、加工效率低,特别是性能指标难以保证等难题。从高端制造装备业的需求出发,提出并阐明了高性能零件的特点、分类以及数字化可控去除加工方式的内涵,在此基础上指出了四类高性能零件精密加工所涉及的关键问题,并着重介绍了这些问题的研究现状、存在的难点和可行的解决方案,为面向高性能要求的性能与几何参数一体化的加工理论、方法和工艺技术体系的建立提供参考,以解决高性能零件的精密制造难题。     

CRUSHING BEHAVIOUR OF ALUMINIUM HONEYCOMBS UNDER IMPACT LOADING

Understanding the crushing behaviour of honeycombs under dynamic loading is useful for crash simulations of vehicles and for design of impacting energy absorbers. Available experimental techniques, however, are not always able to provide satisfactory precision for tests on honeycombs under impact loading. This paper presents a new application of the Split Hopkinson Pressure Bar (SHPB) for testing honeycombs. Viscoelastic bars are used to improve the accuracy of measurements, and a generalised two-strain measurement method is applied to obtain a sufficient measurable maximum crush (up to 80%). Original experimental data (especially in the in-plane crushing directions) under impact loading are then reported. Differences between quasi-static and dynamic results are discussed.     

Development of a Drop Tester for Portable Electronic Products

1 IntroductionRapid developments in the electronics industry have brought about a huge increase in the usage ofportable electronic products such as cellular phones and PDA,MP3, pagers. These products are sus-ceptible to accidental drop impact which can cause various functional and physical damage such as in-terconnect breakage, shield-housing fracture, Liquid Crystal Display (LCD) cracking, solder jointbreaking and battery separation in cellular phones. These products can be subjected to v…     

基于 HP VEE 的电磁辐射自动测试软件设计

介绍了信息电子设备电磁辐射测试的条件、要求和测试方法. 详细讨论了如何用 HP VEE 可视化编程语言实现基于 GPIB 总线的电磁辐射自动测试软件设计的思路、结构及组成. 本文的设计方法和设计思路适用于计算机系统以及其他电子设备的电磁辐射测试.     

Application of hardware reliability calculation procedures according to ISO 26262 standard

The second edition of standard ISO 26262 (ed. 2018) for functional safety assessment in the automotive industry requires a hardware evaluation using the probabilistic metric for random hardware failures (P_MHF). The standard for mentioned purpose highly recommends the fault tree analysis (FTA) utilization but does not give any specific calculation example. Therefore, this article describes computational procedures with derivation and explanation of mathematical formulas for various hardware architectures of electronic systems. Described formulas consider impact of multiple failures and impact of elf-tests, but formulas are relatively simple. This simplicity allows them to be used in the early stages of hardware development when frequent hardware design changes can be expected. Thus, the article with attached case study is intended not only for scientists but also for developers of critical safety–related electronic systems in the automotive industry.     

电子电气产品中限用物质的国际标准化研究

电子电气产品中限用物质的管理是电工行业面临的新挑战,为了帮助业界全面、正确地做好应对工作,需要对相关国际标准化工作的动态进行分析和研究。作为新成立的国际电工委员会电子电气产品和系统的环境标准化技术委员会,正在开展一系列的标准化起草工作,旨在系统地解决电工产品的环境问题。为了维护我国的产业利益,我国参与了IEC/TC111标准制定工作并积极提交新标准提案。在中国的机械拆分提案中首次提出非均质检测单元、最小拆分单元、风险评估、归类合并等概念,并得到成员国的普遍接受。