2mm HM连接器短路失效分析

通过对2mm HM连接器发生安装短路失效分析发现:连接器端子间多余物是引起该短路故障的主要原因。该多余物为连接器端子冲压时因冲裁不彻底而残留的金属屑。卡在连接器端子与塑胶壳体间的金属屑,在PCBA组装压接过程中,刺破PCB阻焊膜,与顶层铜箔相连,造成短路失效。只有严格控制连接器生产工艺,加强质量检验,才能避免连接器安装短路故障的发生。     

Short- and long-term performance of the “Tecnaria” stud connector for timber-concrete composite beams

The paper presents the results of some experimental tests performed on the shear stud connection system for timber-concrete composite beams manufactured by the Tecnaria Ltd. Some push-out specimens constructed using both normal weight (NW) and light weight (LW) concrete were subjected to collapse and long-term creep tests. During the collapse test, the connector exhibited significant strength and stiffness. In the creep test performed in constant environmental conditions, delayed (creep) deformations took place mainly during the first days after loading. The next part of the creep test, conducted under cycles of environmental relative humidity, was characterized by an increase in delayed deformations (the so-called mechano-sorptive effect) due to the hygroscopic behaviour of timber around the connector. The amount of delayed deformation depended upon the cycle duration and was negligible for short period (less than one week) cycles. The use of LW concrete instead of␣NW concrete was found not to significantly affect␣the performance of the connection system␣neither in the long-term, nor in the collapse tests.     

Microstructure of External Stress Whiskers and Mechanical Indentation Test Method

Lead-free commercial products have been dramatically increasing in the world markets as the restriction of certain hazardous substances (RoHS) directive in the European Union has been enacted. At the same time, the problem of “tin whiskers” has become one of the most serious problems in the industry. Growth of tin whiskers is believed to be related to residual stress inside the tin plating film and external compressive stress. Whiskers in fine-pitch connectors have affected the practical production of advanced digital equipment. The Japan Electronics and Information Technology Industries Association (JEITA) has proposed a new testing method to evaluate tin whiskers, especially for the fine-pitch connectors. This paper describes the microstructures of external stress whiskers and the mechanical indentation test method.     

钢结构柱脚抗剪键设计方法研究

为确定钢结构柱脚中抗剪键的设计难题，考虑抗剪键与混凝土的协同作用效应，基于Timoshenko梁理论，分别按混凝土应力 应变关系的线弹性和非线性模型推导了抗剪键设计埋深的微分方程.对非线性模型的微分方程采用Galerkin法简化为代数方程，通过数值计算得到了抗剪键的理论埋深值，并建立了可供实际应用的计算表格.计算结果表明，按线弹性理论计算的抗剪键埋深偏小，偏于不安全.抗剪键的设计埋深主要与抗剪键的截面有效回转半径、考虑抗剪键与混凝土相对刚度的抵抗惯性矩及抗剪键承担的剪力大小等3个因素有关     

典型电缆连接器的装配质量控制措施

电缆连接器广泛应用于航空航天、军工、电子产品等领域,为了保证产品的质量,提高产品的可靠性,有必要对其进行研究.主要介绍了XKE型和SCSI型及J30J型电缆连接器的特性、用途和装配工艺控制措施.通过实际应用,取得了较好的效果.     

基于ANSYS的光纤连接器端面抛光仿真研究

主要利用ANSYS软件对光纤连接器抛光时端面接触压强分布的仿真分析,又与实际情况进行比较,证明分析是正确的,从而为光纤连接器端面抛光的优化分析提供了充分的理论依据。     

电连接器接触件应力场的数值分析与试验验证

利用ANSYS对某型号电连接器接触件应力场进行分析,以寻找应力变化规律.对接触件应力场分布特点、插孔形变、接触压力随温度升高的变化规律进行了仿真研究,并进行数据分析与接触压力的试验验证.结果表明:随着温度升高,插孔最大形变量增加,最大接触压力和接触压力区域都有所减少;尺寸较小的接触件插孔槽缝底部最大等效应力随温度升高增幅较大,交变载荷作用时易出现疲劳、破裂等,属产品失效薄弱点.通过分析得知最大等效应力值随温度上升而变化的趋势取决于温度软化效应和热应力增强作用的综合结果;仿真结果能较好地反映电连接器的工作应力状态,接触压力试验验证了有限元仿真方法的可行性.     

管线焊制三通的价值

介绍了中、高压管线系统中焊制三通的具体制造情况，该三通具有合理的对口标准、严格优选的焊接工艺和热处理工艺，并且克服了延迟裂纹及拘束应力过大等不利因素。经实际生产证明，焊制三通只需铸造三通及锻造三通1/10的制造费用，就可长期安全运行。     

波纹连接器圆弧密封环槽加工的车床夹具设计

波纹连接器的毛坯精密铸造而成,材料为Q235-A。根据波纹连接器零件的结构特点,合理选择工件的定位与夹紧方式,设计出车床夹具的结构图。该夹具采用两端夹紧方法,结构简单、操作方便,降低了工人的劳动强度,提高了生产效率。     

接线片多工位级进模设计

分析了接线片零件的成形工艺，详细介绍了排样设计、工艺计算、模具结构设计、以及一些常见问题的处理方法。