Application of nonlinear fatigue damage models in power electronic module wirebond structure under various amplitude loadings

This paper presents mean fatigue lifetime predic- tion of a wire-bond structure model in power electronic module using a failure physics approach that integrates high fidelity modelling and reduced order modelling. Loading current with variable amplitudes is applied to a finite element model of simplified wirebond structures. The resulting accumulated fatigue damage due to random loads is predicted by using reduced order modelling based on failure physics, a cycle counting algorithm, and various nonlinear fatigue damage models widely used in the literature. The reduced order mod- elling approach based on failure physics uses prediction data for the electro-thermo-mechanical behaviour of the wire-bond design of a power module obtained through non-linear transient finite element simulations, in particular for the fatigue life-time of the aluminium wire attached to the silicon chip of the wire in the module. The reduced order models that capture the black box function of the accumulated plastic strain are used in pre- dicting the mean fatigue life time of the wire bond structure under random loads. One of the widely used cycle counting algorithms, rainflow counting algorithm, is used to count cycles of the temperature profile at the specific point of the wire bond structure in a power electronic module. The cycle data from the rainflow algorithm mean life time of the wire bond structure are predicted with various cumulative fatigue models. Non-linear cumulative fatigue models such as damage curve approach （DCA）, double linear damage rule （DLDR）, and double dam- age curve approach （DDCA）, and linear cumulative fatigue damage model such as Palmgren-Miner rule are used to predict the mean fatigue life of the wire bond structure, and the results are compared.     

环境侵权精神损害赔偿自然人权利主体类型化探析

人类赖以生存的环境蕴涵着巨大的精神利益,这些利益理应为每个人所享有.探讨环境侵权精神损害赔偿自然人权利主体的类型化,既是对人获得良好生存环境和精神享受利益的关注,也是完善环境保护法与精神损害赔偿制度的重要方面.环境的污染和破坏必将损害人的环境性精神利益,从更全面地维护人获得良好生存环境和精神享受利益的角度看,环境侵权精神损害赔偿的权利主体应是自然人而非公民.将权利主体类型化为直接受害人与间接受害人,并探讨尚有争议的一些特殊群体,如第三人、后代人及胎儿、欠缺感知能力者等在其中的地位,将符合法理的纳入权利主体范围.     

拳击的运动损伤预防与恢复

运动损伤的预防与救护对于运动员意义重大。文中从分析拳击运动损伤的原因、类型,并根据自己多年从事比赛,训练的经验提出针对性的预防措施救治方法,为运动员及教练员的训练提供一定的参考。     

HERIe: A Web-Based Decision-Supporting Tool for Assessing Risk of Physical Damage Using Various Failure Criteria

ABSTRACT

HERIe is a web-based decision-supporting software tool to facilitate the management of collection environments by precise assessment of climate-induced risk of physical damage to vulnerable objects. The software translates the relative humidity and temperature data recorded in the environment of the analysed object into a strain history experienced by it, and estimates the risk of physical damage using selected failure criteria. As all information is pre-calculated for the user, no engagement in complex and time-consuming numerical simulations is required. HERIe is available for testing at herie.mnk.pl. Detailed information on the methodologies used by the software is available at the above website which also contains tutorial climates. The current work aims at refining HERIe by selecting the damage criteria not only from laboratory studies but also from direct monitoring damage accumulation in objects, especially using the acoustic emission method. The software has been expanded to include moisture-induced response of parchment to support managing environments in libraries and archives.     

山区农民服用假药行为的实证分析--对浙江省文成县山区农民服用假药的情况调查

本文以浙江省文成县山区农民服用假药的情况调查为基础，实证分析了山区农民服用假药的经济、社会、文化等方面的原因。山区尤其是欠发达地区农民主动服用假药及其对假药的信任和依赖暴露出我国在打击假药和发展农村医疗、社会保障、教育等社会事业方面的缺陷。笔者通过调查分析，提出了解决问题的对策与建议。     

浅淡民国文献的抢救与保护

民国时期出版的文献是一批非常重要的文献,其思想文化价值不在善本古籍之下。但是,由于民国时期的造纸状况和现代人对民国文献保护的意识不强,造成了民国文献的酸化和老化损毁状况极为严重。因此,加强对民国文献的抢救与保护具有十分重要的意义。本文旨在为民国文献的保护提出自己的一点见解,以供同行参考。     

有无正当理由违约中的损害赔偿——从案例分析的角度

通过对国际体育仲裁违约合同造成损害赔偿的案例分析,提出没有固定的规则可以适用所有的案例,唯一确定的是所谓的"积极利益"或"预期利益"原则。因此,裁定方确定赔偿金是以假设违约未发生,受害方应当获得利益大小为标准。任何人都不应当试图创设一个固定规则,因为尝试创设规则是不明智的,它将导致裁定方因固定规则被迫以某种方式裁定,并不能实现双方当事人及体育领域所追求的公正、合理的结果。文章认为由裁定方在考虑到所有情形的前提以积极利益原则为首要原则确定最合适的赔偿金。     

Report:Influence of freezing rate on cryo-damage of cementitious material

We report an experimental investigation on the impact of the freezing rate on the cryo-deformation and cryo-damage of cementitious materials. Saturated, dried and air-entrained mortar specimens are subjected to laboratory freeze-thaw cycles under three freezing rates without moisture exchange with the environment. In addition to basic mechanical properties and pore distribution, the measurement is also effectuated for freezing expansion, residual deformation of the specimens in each cycle. From the results it is observed that a high freezing rate does augment the freezing expansion of material while the cryo-damage is more important for a low freezing rate. Accordingly, both the freezing rate and freezing duration should be taken into account for the cyro-damage extent of cementitious materials.     

Social media crowdsourcing for rapid damage assessment following a sudden-onset natural hazard event

Rapid appraisal of damages related to hazard events is of importance to first responders, government agencies, insurance industries, and other private and public organizations. While satellite monitoring, ground-based sensor systems, inspections and other technologies provide data to inform post-disaster response, crowdsourcing through social media is an additional and novel data source. In this study, the use of social media data, principally Twitter postings, is investigated to make approximate but rapid early assessments of damages following a disaster. The goal is to explore the potential utility of using social media data for rapid damage assessment after sudden-onset hazard events and to identify insights related to potential challenges. This study defines a text-based damage assessment scale for earthquake damages, and then develops a text classification model for rapid damage assessment. Although the accuracy remains a challenge compared to ground-based instrumental readings and inspections, the proposed damage assessment model features rapidity with large amounts of data at spatial densities that exceed those of conventional sensor networks. The 2019 Ridgecrest, California earthquake sequence is investigated as a case study.     

四川省水上运动学校赛艇运动员损伤原因调查分析

本文通过运用问卷调查法、文献资料法、访谈法和统计法等研究方法,对四川省水上运动学校赛艇运动员常见运动损伤原因进行研究。研究发现：赛艇运动员在一年内都有损伤,容易损伤部位主要是腰部和肩部,出现损伤季节主要是10—12月和1—3月,损伤原因主要是身体疲劳。本次研究对赛艇运动员的损伤特点,提出相应的预防措施减少损伤,为更好的提高赛艇运动员水平提供科学的理论依据。