基于电压电荷法的静电放电能量检测方法

传统的静电放电能量检测方法多依赖于经验公式,方法简单,计算误差较大。根据电压电荷法计算静电放电能量的原理,设计并搭建了实验系统,开发了基于MATLAB APP Designer的静电放电能量计算软件,并结合静电火灾事故调查实例验证其的科学性,为静电事故的预防与调查提供技术手段。     

基于有限元分析的钢包回转台优化设计

某钢厂大包回转台由Daniel设计,2003年扩容后增加过渡段,造成大包回转台倾覆力矩增加,载荷频繁冲击造成过度段出现裂纹,采用有限元算法,建立实体模型,对载荷冲击对过度段影响进行模拟,进一步优化设计,延长大包回转台使用寿命。     

冷弯厚壁型钢轴压构件设计可靠度分析

在材性试验的基础上对冷弯厚壁型钢进行了轴压承载力试验及有限元分析。试验中发现：对于长细比较大、板件宽厚比较小的试件,破坏模式为整体失稳;对于长细比较小、板件宽厚比较大的方管柱,其破坏过程首先是柱中部产生很小的弯曲变形,随着荷载增大,整体弯曲变形也逐渐增大,并引起方管板件的局部屈曲。采用ANSYS软件进行有限元分析,其结果与试验结果接近,表明将残余应力引入有限元模型对冷弯厚壁型钢构件进行分析具有较高的精度。在此基础上,利用收集到的26组不同牌号、不同截面冷弯厚壁型钢的试验数据建立有限元模型,并引入已有的残余应力模型进行了大量的有限元分析,得到了多组冷弯厚壁型钢轴心受力构件的承载力。对冷弯厚壁型钢构件进行了设计可靠度分析,提出了Q235、Q345冷弯厚壁型钢的抗力分项系数和强度设计值的建议值,可为相关技术标准的修编提供依据。     

扩大十字形截面型钢混凝土柱-SRC梁节点抗震承载力试验研究

提出了内置扩大正、斜向十字形截面型钢混凝土柱-工字钢型钢混凝土（SRC）梁节点的构造方式。通过对4个内置扩大正十字形和斜向十字形截面的型钢混凝土柱-SRC梁节点试件和1个内置普通十字形截面型钢混凝土柱-SRC梁节点试件的低周反复荷载试验,研究了试件的破坏特征、滞回曲线、骨架曲线、剪切变形和钢材应变,分析了配钢形式、加载角度和构造措施（直接焊接、竖向隔板连接）对节点受力性能的影响,并在此基础上对节点核心区受剪承载力进行了计算。试验结果表明：上述两种新型截面型钢混凝土梁柱节点均发生节点区剪切破坏,达到极限状态时,节点区箍筋及型钢腹板应力均达到屈服强度,试件型钢及翼缘框内混凝土仍能承担较大荷载,并趋于稳定;新型SRC梁柱节点核心区剪力-剪切角滞回曲线饱满,无捏缩现象,其受剪承载力比相同破坏模式的普通型钢混凝土梁柱节点试件大;柱内采用斜向布置十字型钢以及梁柱正交时,节点试件的剪切承载力更大,所提出的两种构造措施对节点承载能力影响不大。     

CFRP条带加固损伤混凝土柱受压性能试验研究

通过对12根采用两种加固率(CFRP加固率30%和50%)加固不同损伤程度的混凝土圆柱进行轴心受压试验,研究持载状态下CFRP布条带约束损伤混凝土柱受压性能,分析损伤程度、初始应力和加固量对混凝土柱的受力性能影响及试件破坏特征。试验及分析结果表明:相同损伤程度的试件,其抗压承载力和延性随CFRP布加固量的增加而增大;CFRP布加固量相同的试件,其极限承载力随着混凝土柱损伤程度的增大而降低,且当损伤程度高于0.6时(混凝土柱出现竖向微裂缝),极限承载力下降较快;CFRP加固率不低于50%时,才能有效地约束混凝土柱,提高其极限承载能力和延性。     

正交异性钢-混凝土组合桥面板截面优化研究

为了比较正交异性钢-混凝土组合桥面板中各个截面参数对组合桥面板截面特性的影响,寻找较为合理的正交异性钢-混凝土组合桥面板的详细尺寸,计算推导了正交异性钢-混凝土组合桥面板的抗弯承载力表达式,分析了截面中不同混凝土厚度、钢板宽度等参数对承载力的影响,利用Matlab编写了计算程序并调用了优化工具箱,得到了不同跨径、不同梁高、不同应力限值下的合理截面尺寸。     

谈岩石隧道突水涌泥后处治措施

介绍了宝塔山隧道3号斜井XK0+283~XK0+291段大规模突水涌泥的过程,并分析了该坍塌段突水涌泥后的治理方案及施工技术要点,以期为今后处治同类工程问题提供参考借鉴。     

输煤管道工程中浅埋长距离小断面隧道施工工艺

以输煤管道项目洛河隧道工程为基础,结合地质条件及工程施工难点,介绍了浅埋长距离小断面隧道施工工艺,对隧道开挖、排渣、支护、通风、排水等系统进行了论述,分析了各工序施工难点和要点,总结了采用浅埋长距离小断面隧道施工工艺特点及效果,取得了良好的经济和社会效益。     

Effects of openings on the punching shear strength of RC flat‐plate slabs without shear reinforcement

Openings in RC flat‐plate slabs are one of the critical factors that influence the punching shear strength of the slab and determine its thickness in the vicinity of the slab‐column joint. This study experimentally investigates the effects of openings on the punching shear strength of flat‐plate slabs without shear reinforcement. Tests were performed on eight flat‐plate slab specimens considering the layout and number of openings as test variables. The failure characteristics of each specimen are examined, and the effects of the test variables on the punching shear strengths of the test specimens are investigated. The measured punching shear strengths of the test specimens are compared with the predictions of several concrete design codes, including the American Concrete Institute (ACI), Comité Euro‐International du Béton and Fédération Internationale de la Précontrainte (CEB‐FIP) model and fédération internationale du béton (fib) model codes. This indicates that the reductions in punching shear strength due to the existence of openings are generally proportional to the loss of effective critical sections, and an L‐shaped opening layout around the corner of the column may further reduce the punching shear strength and may contribute to the loss of effective critical sections due to the existence of openings. Copyright © 2015 John Wiley & Sons, Ltd.     

Experimental study on seismic performance of mega steel‐reinforced concrete columns subjected to cyclic loads

In recent years, mega steel‐reinforced concrete (SRC) columns have been applied in super tall buildings. The previous research on SRC columns mainly focuses on the components with simple arrangement of shaped steel, such as H‐shaped steel and cross‐shaped steel, with little attention paid to mega SRC columns, which always have complicated encased steel and large steel ratio. The cyclic loading tests were carried out on scaled mega SRC column models with different cross‐section type of encased steel and steel ratio. The principal damage states were investigated throughout the entire testing process. Based on the test results, the effects of steel ratio and the cross‐section type of encased steel on the damage characteristics, hysteretic behavior, ductility, secant stiffness degradation, energy dissipation capacity and maximum crack width were analyzed. The test results indicate that the steel ratio has significant effect on the seismic performance of mega SRC columns while the effect of cross‐section type of encased steel is not significant. Copyright © 2015 John Wiley & Sons, Ltd.