基于加速模态差值法的桁架结构早期损伤识别研究

针对起重机械的桁架结构,分析了损伤的严重后果,提出了用加速模态差值法识别早期损伤.首先建立有限元模型,随机选取一根杆件,通过降低其刚度来模拟早期损伤;然后对未损桁架和损伤桁架分别进行模态分析,并提取两者的模态振型数据,通过计算机处理得到损伤前后的加速模态振型,然后进行对比分析,找出加速模态振型变化最大的节点,即为损伤节点,进而找到损伤杆件.实例分析表明,提出的方法合理可行.     

潜孔钻机钻臂虚拟样机建模与动力学仿真

研究潜孔钻机优化定位和结构设计问题,潜孔钻机钻臂是一种复杂的多关节机构的特点,传统的方法采用机器人动力学模型求解困难。为了提高设计的可靠性和有效性,提出一种虚拟样机技术进行设计,建立仿真系统。首先采用Pro/E和ADAMS建立钻臂虚拟样机模型,再结合实际工况对钻臂四个典型动作进行动力学仿真,得到各液压缸受力变化曲线。实验结果进行了对比。实验表明仿真模型和仿真结果合理可靠,为进一步进行钻臂设计和研究提供了可靠的参考依据。     

大型矿用液压挖掘机动臂系统仿真与实验研究

针对大型矿用液压挖掘机产品开发成本较高与开发周期较长的现象,以国内某企业125 t大型矿用液压挖掘机为研究对象,对其动臂系统进行分析。建立挖掘机三维模型与液压系统仿真模型,对其进行联合仿真,并通过试验进行验证。仿真与实验结果表明:仿真模型能正确模拟实际动臂液压系统,通过合理建模与仿真可对挖掘机液压系统进行深入的研究,并对企业今后设计制造挖掘机提供参考。     

方形焦罐吊杆偏移的原因与处理

介绍了方形焦罐出现吊钩偏移的原因和采取的相应改进措施。     

臂架疲劳试验台系统研究与仿真

基于臂架实测载荷及其响应信号的分析结论,设计出了满足要求加载形式的臂架疲劳试验台系统,并且利用AMESim软件,建立试验台液压系统的计算机仿真模型,进行了必要的系统动态仿真分析,为疲劳试验台的运行提供适合的控制策略。     

‘New Aging’: Designing Architecture for All Ages

The US is on the brink of demographic transformation, with the bulging generation of baby boomers about to reach retirement. In 2008, New York-based architects Hollwich Kushner (HWKN) anticipated this shift by instigating a ‘New Aging’ initiative that set out to explore imaginative solutions in architecture and urbanism to age-related challenges. Here Matthias Hollwich with Matthew Hoffman of HWKN explain why attitudes and approaches to ageing have to change; and why old age needs to be ‘acknowledged as a state of human existence’ that fully ‘deserves preparation, anticipation and excitement’.     

Design and development of large-scale in-situ PRACLAY heater test and horizontal high-level radioactive waste disposal gallery seal test in Belgian HADES

In Belgium,the Boom clay was selected as a potential host formation for the disposal of high-level radioactive waste（HLW）.To demonstrate the suitability of Boom clay for bearing thermal load induced by the HLW,a large-scale in-situ heater test,called PRACLAY heater test,will be conducted in the underground research laboratory（URL） in Mol.Owing to the limitations of the test（a short period of time compared with that considered in a real repository,different boundary conditions,etc.）,the test is designed to simulate,in a conservative way,the most critical state and phenomena that could occur in the host rock.The PRACLAY gallery was excavated at the end of 2007;the heating phase will begin in 2010 and will last for at least 10 years.The PRACLAY gallery itself leaves an opportunity to study the possibilities of sealing a disposal drift in Boom clay and testing the feasibility of hydraulic cut-off of any preferential pathway to the main access gallery through the excavation damage zone（EDZ） and the lining with a seal in a horizontal drift（horizontal seal）.Indeed,this is a generic problem for all deep geological disposal facilities for HLW.An annular seal made of compacted swelling bentonite will be installed in the front of the heated part of the PRACLAY gallery for these purposes.This paper provides detailed considerations on the thermo-hydro-mechanical（THM） boundary conditions for the design of the PRACLAY heater test and the seal test with the support of numerical calculations.It is believed that these important items considered in the PRACLAY heater test design also constitute key issues for the repository design.The outcome of the PRACLAY heater test will be an important milestone for the Belgian repository design.     

QLY2150型动臂风电吊机液压系统设计

QLY2150型动臂风电吊机是郑州新大方重工科技有限公司针对中国风场建设的需要,研制开发的具有自主知识产权的大型特种专用起重设备。吊机分上车和下车两部分,上车结构形式新颖,吊运吨位大,由微电系统控制、协调和实现各系统的功能,下车采用全液压传动,全车每一悬挂均可旋转100°,为独立回转型,可实现直行、以任意角斜行、横行3种转向模式,该机机械化和自动化程度高,是机电液控为一体的特种设备。介绍QLY2150型动臂风电吊机性能特点、技术参数,以及液压系统的工作原理和设计思路。     

On the chemo-thermo-hydro-mechanical behaviour of geological and engineered barriers

An overview of the recent findings about the chemo-hydro-mechanical behaviour of materials used for both geological and engineered barriers in nuclear waste disposal is presented, through some examples about the natural Boom Clay (BC) and compacted bentonite-based materials. For the natural BC, it was found that compression index identified from both oedometer and isotropic compression tests is similar and the compressibility of BC from the Mol site is higher than that of BC from the Essen site; the shear strength of Mol BC is also higher than that of the Essen BC, suggesting a significant effect of carbonates content; the thermal volume change is strongly overconsolidation ratio (OCR) dependent—low OCR values promote thermal contraction while high OCR values favour thermal dilation; the volume change behaviour is also strongly time dependent and this time dependent behaviour is governed by the stress level and temperature; the effect of pore-water salinity on the volume change behaviour can be significant when the smectite content is relatively high. For the bentonite-based materials, it was found that thermal contraction also occurs at low OCR values, but this is suction dependent—suction promotes thermal dilation. Under constant volume conditions, wetting results in a decrease of hydraulic conductivity, followed by an increase. This is found to be related to changes in macro-pores size—wetting induces a decrease of macro-pores size, followed by an increase due to the aggregates fissuring. The presence of technological voids can increase the hydraulic conductivity but does not influence the swelling pressure.     

动臂变幅起重机起重臂防后倾支撑装置的优化改进

由一起动臂变幅门座式起重机使用过程中起重臂折断事故引发思考,对起重臂防后倾支撑装置进行改进,提出在设计该装置时运用“优先破坏”原则,使该装置确实实现安全保护功能.