钢管混凝土构件在爆炸冲击荷载作用下的动力仿真分析

采用有限元分析软件ANSYS/LS-DYNA对圆钢管混凝土结构构件在爆炸冲击荷载作用下的动力响应特性进行了数值模拟.通过分析钢管混凝土构件在不同折合距离下的侧向位移和核心混凝土的失效破坏情况,得到在爆炸冲击荷载作用下随着折合距离的增大,钢管混凝土构件的整体变形逐渐减小,钢管和核心混凝土的破坏程度也逐渐减小,特别是当折合...     

冈管混凝土复合构件抗爆性能分析

采用有限元分析软件ANSYS/LS-DYNA对不同壁厚的圆钢管混凝土构件和单钢管构件在爆炸荷载作用下的动态响应进行了数值模拟.通过分析两种构件在相同爆炸荷载作用下的最大挠度,得出钢管壁厚1.8～2.5mm时,复合构件的抗载能力远大于单钢管构件,壁厚大于2.5 mm时,复合构件的优势明显减弱.最后根据多项式拟合的方法,得...     

爆炸荷载作用下SRC柱中混凝土的断裂破坏原理

以计算机模拟为手段,研究分析了SRC(Steel-Reinforced-Concrete,简称SRC)柱在爆炸冲击荷载作用下钢骨周围混凝土的断裂破坏原理.发现由于所受爆炸冲击波荷载性质的不同,SRC柱中的混凝土可以分为3种破坏模式:冲击波直接破坏、冲击波冲量破坏和冲击波能量破坏.该研究成果不仅为进一步研究SRC柱在爆炸冲击荷载作用下的破坏模式提供了研究基础,并且为SRC柱的抗爆设计和抗爆加固提供了指导作用.     

工业厂房钢管混凝土柱设计

结合工业厂房特点,分析了钢管混凝土柱材料的搭配,运用合理的设计方法,把钢管混凝土柱高承载的能力体现出来,满足现代工业厂房的要求,达到节约钢材的目的.     

预应力梁结构响应的简要荷载试验法研究

根据简要荷载试验方法,对预应力梁的结构响应进行了研究。采用单级加载的方法,以加载车在主梁控制截面处事先确定的几个停留位置,测量相应的各主梁控制截面处的挠度。依据实测主梁挠度,根据相关数理统计理论,建立主梁的荷载-挠度方程,对主梁在预期较高荷载标准车辆或重车作用下的跨中最大挠度进行预测,从而完成对钢筋混凝土简支梁桥的承载能力预测工作。通过与实桥试验数据对比可知,简要静荷载试验方法能对预应力混凝土梁在正常使用阶段的行为进行有效预测,易于在实际工程中的应用。     

吊索与钢管混凝土拱桥新型连接节点承载性能试验研究

随着经济的发展,我国的桥梁建设事业取得了较为重大的发展。其中,拱桥在建设的过程中需要面临一些技术方面的难题,针对其进行研究,对于拱桥的建设能够起到较为良好的现实作用。吊索与钢管混凝土连接点能够在技术方面为拱桥建设提供较为良好的支持。本文对吊索与钢管混凝土拱桥的关系进行探索,明确了吊索对钢管混凝土拱桥的作用,选取相应的实例,采取具备较强针对性的现实分析方法对其整体状况进行分析,最后对吊索与钢管混凝土拱桥新型连接节点设计与承载性能进行解析。     

点支式玻璃板在爆炸与冲击荷载下的动力特性

为了研究点支式玻璃板在动态荷载下的性能,基于玻璃板的动态响应理论,利用LS-DYNA有限元程序,对点支式玻璃板在冲击荷载及常规爆炸荷载下的抗爆性能进行分析,讨论了冲击荷载与常规爆炸荷载对点支式玻璃板动力响应的影响,以及玻璃板的动力放大系数及其与荷载峰值之间的关系,并与试验结果进行了对比分析。结果表明:近似于静力加载及冲击荷载下玻璃板的性能响应与试验结果吻合较好;加载时间对玻璃板的动态响应影响显著;不同的荷载作用方式,即冲击荷载和爆炸荷载对点支式玻璃板的位移响应不同;缓解点支式玻璃板支座处孔边应力集中能显著提高玻璃板的抗爆性能。     

原位荷载试验在工程检测鉴定和加固维修方面的应用研究

原位荷载试验是工程施工过程中确定承载能力的重要方法.以确定复合地基的承载能力和加固修复后的梁板承载能力为主要的研究载体,讨论原位荷载法在这两类常用应用场景中的具体应用方法,包括荷载检测方法、加载方式、试验数据的收集和分析等,为工程质量提供实际的参考.     

柱形爆炸容器的振动特性研究

根据唐纳尔简化理论，推导了柱形爆炸容器固有频率的计算公式。在三次不同当量的化爆试验中，测量了容器爆心截面部位的环向应变，研究了应变的响应行为，对应变波形进行了频谱分析。     

混凝土搅拌车关键部位动态应变测试实验研究

混凝土搅拌车副车架和支撑部位动态应力和应变的实际变化,对车架的设计和设备的使用非常重要。采用现成的应变遥测装置Torque Trak9000,对混凝土搅拌车在实际工况下的多点应变进行了测试和研究,测试结果可以为设计部门、制造厂家和使用单位提供依据。     

钢珠对磁力抛光工艺影响规律的实验研究

磁力抛光机利用磁场的力量,引导磨具(磁针)做快速旋转运动而抛光工件。为了使磁力抛光机对45钢轴的抛光效果及效率更佳,从理论上分析了磁力抛光的工作原理、磁力抛光过程中磨具的运动方式和影响磁力抛光效率的因素,提出加入钢珠会提升抛光效果及效率,并对45钢轴进行磁力抛光实验。实验结果表明:加工频率、磁针长度均对抛光效果及效率有不同程度的影响;加入钢珠后,抛光效果及效率都有提升;最佳磁针与钢珠的质量混合比例为1∶3。     

硬车代磨表面粗糙度试验研究

使用硬质合金刀具、陶瓷刀具和PCBN刀具对渗碳淬硬钢20CrMnTi进行干式车削试验,通过测量不同切削条件下的表面粗糙度值,得出切削速度、进给量对表面粗糙度的影响规律,验证了以车代磨的干式切削渗碳淬硬钢20CrMnTi的可行性.     

淬硬钢Cr12高速铣削力实验研究

对淬硬钢Cr12进行了高速铣削实验研究,研究了铣削速度、背吃刀量、进给速度对铣削力的影响。研究表明:铣削力随着铣削速度的增加而减小,当铣削速度增加到一定的值后其下降趋势变得平缓;铣削力随背吃刀量的增大而增大,且变化显著;铣削力随进给速度的增加而增加,但增加不大。     

The study of cooling channel optimization in blast furnace cast steel stave based on heat transfer analysis

The three-dimensional heat transfer and thermal stress of a steel cooling stave in a blast furnace at Maanshan Iron and Steel Co. Ltd. are built. The temperature and thermal stress fields of cooling stave are calculated by using finite element method software ANSYS. The results show the rise in maximum temperature and thermal stress of the stave hot surface is not high when cooling pipe is replaced by cooling elliptical tube. Because of the decrease in the cross-sectional area for cooling elliptical tube, the thickness of the cooling stave is reduced and cooling water flow is saved. As a result, the iron-making cost can be reduced.     

The influence of elastic shear deformation on the transverse shear failure of a fully clamped beam subjected to idealized blast loading

The influence of elastic shear deformation on the transverse shear response of a fully clamped beam is investigated in the present paper. The beam is made from a rigid, perfectly plastic material and subjected to a uniformly distributed pressure pulse loading. The elastic shear deformation is idealized by an elastic, perfectly plastic spring with a constant spring coefficient. Analytical solutions are obtained for the transverse shear response, which are then used to predict the occurrence of a transverse shear failure. The method presented in the paper may be extended to study the blast-induced shear failure of other structural elements when the elastic shear deformation needs to be considered.     

Experimental studies on performance of reinforced concrete beam strengthened with CFRP under cyclic loading using FBG array

Investigations are increasingly being carried out in the area of utilizing Fiber Reinforced Plastic (FRP) materials for retrofitting and repairing existing damaged concrete structures due to their excellent properties. Favorable mechanical and material characteristics of FRP composites make them attractive for strengthening applications, whereas relatively higher material costs, insufficient knowledge in mechanics of their behavior, long-term durability and lack of related design codes are the issues that need to be addressed for mainstream application of these materials. Although there has been growing interest and field applications of strengthening concrete structures using Carbon Fiber Reinforced Plastic (CFRP) sheet/plate, very little information exists regarding the flexural fatigue behavior of reinforced concrete beams strengthened with CFRP. A common cause of failure in such strengthened members is associated with the debonding of CFRP substrate from the concrete in an abrupt manner. In order to understand the mechanism of debonding in strengthened concrete structures, embedment of strain sensors (Fiber Bragg Grating (FBG) array) between the concrete and CFRP is proposed in this paper. Due to the compatibility with CFRP material and being small in size, fiber optic sensor is a good choice for embedding at the interface to measure interfacial strain. This paper presents the experimental studies carried out on CFRP strengthened concrete members subjected to cyclic loading. A special emphasis has been placed on understanding the failure pattern using the embedded FBG sensors. Based on the studies it is concluded that the strain at the interface of CFRP strengthened concrete members can be measured.     

Experimental study on the cyclic deformation and plastic flow of U71Mn rail steel

The strain cyclic characteristics and ratcheting behaviour of U71Mn rail steel were experimentally investigated under uniaxial cyclic loading at room temperature. The effects of cyclic strain amplitude, mean strain, strain rate and their histories on strain cyclic characteristics were studied. The effects of stress amplitude, mean stress and their histories on the ratcheting under asymmetrical stress cycling were also analysed. Then, the interaction between strain cycling and stress cycling was discussed, too. Based on the experimental stress–strain data, the plastic flow properties of U71Mn rail steel under cyclic loading were analysed. Plastic modulus and its evolution rule were calculated from experimental data and were discussed under strain and stress cycling, respectively. It is shown that both the strain cyclic characteristics and ratcheting depend not only on current loading state, but also greatly on previous loading history. Under asymmetrical stress cycling, the evolution rule of plastic modulus is different from that under strain cycling. The strain cyclic characteristics and ratcheting behaviour of the material can be described essentially by the evolution of plastic flow.