Plastic deformation of ship plate subjected to repeated patch loads at different locations - Elastoplastic numerical analysis and design equation

Ship structures may be subjected to repeated random patch loads at different locations. Under these circumstances, ship plates will have large accumulated permanent deformations, which will result in some serious negative effects on their work and safety performance. Therefore, the elasto-plastic response of ship structure under repeated patch loads at different locations are studied by using finite element method. The permanent deformations of plate in the whole loading and unloading process are investigated. In addition, the residual stress and plastic strain states of the panel and stiffeners are studied based on a typical wheel-on-deck interaction scenario. Moreover, according to Hughes's hypothesis, the equivalent method between repeated patch loads at different locations and full uniform pressure load is studied. Considered the influence of plate slenderness, the improved formula for equivalent load coefficient is proposed, showing a good correlation with experimental data and numerical results. The proposed equivalent method can be used for estimating the permanent deformations of ship structures under repeated patch loads at different locations in ship life.     

塑料排水板在软土路基处理中的应用

应用塑料排水板来处理软土路基,原理是将地基中的水排出、土颗粒有效固结,使地基强度提高,主要适用于不能满足工后沉降要求的一般路段。通过丹海高速公路项目塑料排水板工程实例,对塑料排水板处理软土路基的设计、施工、质量检验等进行了简要介绍。     

抗震设计中结构延性与地震作用关系分析

利用延性理论,研究地震作用力对高层结构的影响,从分析延性的各因素入手,构建相应的理论体系,得出相应的延性系数,对高层结构延性研究有一定的参考意义。     

大跨度隧道动态施工力学响应的数值分析

文章以重庆建新坡隧道为例,对大跨度隧道施工过程中的围岩应力和塑性区变化进行了FLAC3D三维数值模拟分析,揭示了围岩应力和塑性区的分布规律,为大跨度隧道工程设计和施工提供参考依据。     

考虑塑性变形的振动压路机非线性动力学仿真

借助于土壤变形的一种塑性模式，提出了一种振动压路机压实过程的非线性动力学模型。在此基础上，借助计算机技术，探讨了振动压实中机架与振动轮的运动规律，并对激振力减少、土壤刚度变大和塑性变形增大等情况进行了仿真研究，发现了一些对压路机设计有参考价值的新现象     

塑料土工格栅加筋土抗拉拔特性试验研究

塑料土工格栅的加筋效果好于其它筋材的原因在于其表面结构特性,它与土之间不仅存在表面摩擦力,而且还存在着镶嵌咬合力,从而增强两者的相互联系,提高接触效率。通过筋材拉出行为试验,进行塑料土工格栅受拉时表面摩擦力分布特征的研究。提出将塑料土工格栅与土体之间摩擦应力的发展过程分为四个阶段的观点,即起始阶段、发展阶段、局部屈服和完全屈服阶段。指出在高围压或长埋深的情况下,筋材会出现拉断破坏,这时的摩擦应力至多经历前三个阶段,而不具备完整的四阶段应力发展模式。     

Analytical modelling of ship bottom grounding considering combined surge and heave motions

This paper provides a new contribution to the analytical treatment of ship grounding accidents. New formulations are proposed to assess the resisting force of outer/inner bottom plating and transverse floors when the vessel undergoes combined surge and heave motions during the grounding event. Considering shallow and sharp rocks described by parabolic functions, analytical solutions are derived from plastic limit analysis and validated by comparison to non-linear finite element simulations. A failure criterion is also proposed to trigger the rupture of the bottom plating and all the derived closed-form expressions are implemented into an in-house solver. The solver is then coupled to a 6-DOFs external dynamics program, which allows to account for the action of the surrounding water. Resulting tool is first validated on a full scale cruise ship by comparison to finite element results. It appears than although some discrepancies arise, especially in the response of transverse floors after rupture, the bottom damage distribution seems to be well predicted. Finally, the developed tool is used to quickly predict the grounding response of different types of ships and the influence of their mass and hydrodynamic properties on the damage extent is investigated.     

塑料铁皮罐压扁打包机的研究和设计

目前市场上机械化的压扁机已应用得十分普遍了,但基本上都是体积庞大、笨重,费用高昂,是专业处理废弃物的设备。文章研究与设计一种专门针对汽车行业的塑料罐和铁皮罐的压扁打包机,体型小巧简单,对废弃品进行压扁和打包,减少存储空间,节约存放和运输成本。     

浅谈汽车外饰塑料件设计缺陷

在汽车造型设计中,汽车造型样式研究可用于指导汽车外观设计。汽车造型风格是对汽车性能、时期特征、市场美学、制造技术工艺、材料应用、人体工程学等因素的综合表达。对汽车外饰塑料零件的设计的理解和认识对于汽车造型设计很重要。文章将研究汽车外饰塑料零件的设计缺陷,为汽车外饰塑料件设计的理论知识奠定基础。     

一种基于车轮固定的汽车防晒装置的设计

本文介绍了一种基于车轮固定的汽车防晒装置,装置利用汽车车轮固定,即防防晒篷被盗,也防汽车被盗,隔热防晒效果可使驾驶台的温度下降16℃,可收放在汽车后背箱内,5座(含)以下小型客车都可使用。