振动筛上振动横梁的疲劳应力分析

根据疲劳应力理论对振动横梁进行了疲劳应力分析,并利用有限元软件Workbench对振动横梁进行了疲劳应力仿真,得到它在正常工作状态下的应力及安全系数分布图。在满足疲劳寿命要求情况下对振动横梁进行了最大循环应力分析,结果表明,振动横梁的疲劳特性符合寿命要求。     

钢混结合梁斜拉桥边跨现浇段支架数值分析

基于有限元分析软件MIDAS/civil对大桥边跨现浇段支架建立分析计算模型。建立模型时,支架底部边界条件设为固结,钢立柱、平联、主横梁、贝雷梁以及分配梁均采用梁单元模拟,钢立柱与主横梁、主横梁与贝雷梁、贝雷梁与分配梁之间均采用主从节点的刚性连接模拟。然后,对支架的强度、竖向位移和整体稳定性进行分析。结果表明:支架的个别构件受力和变形值较大,施工过程中应加强观测。     

基于传统方法和有限元仿真的某大型龙门架强度分析

利用UGNX6.0建立了某大型龙门架的三维模型.先用传统计算方法对设计的龙门架的横梁结构进行了强度计算,然后基于大型有限元计算软件MSC.NASTRAN对其强度进行了仿真计算.对两种方法的计算结果进行了比较,偏差只有3.9%,从而验证了龙门架强度校核结果的正确性,为以后此类龙门架结构的优化设计提供了理论参考.     

基于有限元的卧式过滤罐结构失稳分析

针对某企业的卧式过滤罐在使用过程中存在失稳、导致腿式支座横梁断裂的问题,利用Creo软件建立该结构的有限元模型,运用Ansys软件对工作过程中卧式结构过滤罐进行有限元模拟仿真,分析罐体、支座的应力与变形,探究其结构失稳的原因,并提出具体的改进方案。     

基于轻量化的物流栏板车车身结构有限元分析

为解决车辆负载过重问题,对铝合金栏板车车身及车架进行三维建模,利用HyperWorks 构建车身及车架的有限元模型。 模拟栏板车满载时的弯曲、扭转、紧急制动和紧急转弯4 种工况,施加相应的载荷与边界条件。 经过有限元仿真分析,获得了该车身(包括车架) 在不同工况下的应力分布状况,在存有较大设计余量的基础上,采用减薄壁厚和移动横梁的方法对车身结构改进。 结果表明:改进后的车身结构能够满足各典型工况的强度和刚度性能要求,质量比改进前减少了5.7%,从而为栏板车的结构设计和改进提供依据。     

塔式起重机的动力特性及地震响应分析

为了分析塔式起重机的动力特性及在不同水平下的地震响应,首先借助ANSYS有限元分析软件,对塔式起重机进行模态分析;其次对塔式起重机的有限元模型分别输入EI Centro、Taft及汶川什邡八角站三种激励地震波,分析塔身和水平横梁节点地震响应,最后讨论塔式起重机的抗震设计要点及隔震措施。结果表明：塔式起重机的塔臂疲劳主要由地震反应谱中的窄带过程控制,反之,塔臂的折断破坏是由宽带过程起主要作用。     

某柴油机连杆强度的有限元分析

有限元分析是柴油机零部件结构强度分析中一种实用、可靠的方法。以某柴油机连杆为研究对象,对其建立实体模型,并利用有限元分析的软件平台,对连杆强度进行分析。在应用有限元方法对柴油机连杆进行静力分析过程中,研究连杆在最大受压状态和最大受拉状态的两个极限受力状态情况,为连杆的改进和设计提供可靠的依据。     

某种皮带卷扬式吊具上横梁裂纹原因分析及加固技术

皮带卷扬式吊具是汽车工业等行业广泛应用的一种悬挂运行式生产设备。无论从安全,还是从设备可利用率等角度,其强度设计都至关重要。针对某种皮带卷扬式吊具上横梁出现裂纹的问题,首先通过受力分析及强度计算,说明了出现裂纹的原因,然后基于易操作性、工期及成本等考虑,给出了一种上横梁加固而非更换的维修方案,并对加固方案进行了校核计算。经生产实践检验,加固后吊具的功能、性能没有任何问题。文中采用的分析和解决问题的方法对处理类似工程问题具有一定的参考意义。     

基于Patran有限元法的焊接螺钉强度分析

在参照焊接螺钉焊接强度实验的基础上,提出了一种基于Patran有限元法的焊接螺钉强度分析方法。首先建立焊接螺钉的三维模型,并通过属性选择、网格划分建立有限元分析模型,通过对边界条件和载荷的设置完成强度求解,然后将有限元分析结果和实验结果进行了对比。同时也分析了气孔缺陷对焊接螺钉强度的影响,该方法对焊接螺钉的设计以及焊接缺陷风险评估具有重要指导意义。     

带无限刚体结构位移法计算分析

为研究无限刚体对结构内力的影响,利用位移法对刚架在荷载作用进行计算分析,并将传统手算结果与ANSYS有限元分析进行比较.计算结果表明,一般不单独取刚结点为隔离体建立平衡条件,可取无限刚体或带有无限刚体的横梁;直接由平衡条件建立位移法基本方程不需要作基本结构在单位位移及荷载作用弯矩图,计算速度较快:当横梁全部为无限刚体时,柱端弯矩趋向为0,相当于提供竖向链杆支座;在结构设计过程中要注意杆件材料刚度变化对结构内力的影响;ANSYS分析结构内力速度较快,数据结果与手算结果一致.     

SKMB-200型转向架构架强度与结构优化仿真分析

以应用于CRH380A型动车组上的SKMB-200型动力转向架构架为研究对象,基于UIC615-4标准计算4种模拟运营工况载荷及一种超常载荷,继而确定仿真分析所需的边界条件.静强度仿真结果表明:模拟运营工况下,构架的最大应力分别为225.7、209.0、250.3和196.2 MPa,超常载荷工况下构架的最大应力为30...     

钢筋增强ECC梁受弯性能的试验及数值研究(英文)

为了研究钢筋增强ECC梁受弯性能,进行了钢筋增强ECC梁和普通钢筋混凝土梁受弯的对比研究.结果表明,相比普通钢筋混凝土梁,钢筋增强ECC梁的受弯承载力和延性分别提高了24.8%和187.76%,并且在梁中用ECC代替混凝土可有效延缓裂缝的发展.此外,采用简化的ECC本构模型对钢筋增强ECC及混凝土梁的受弯性能进行了非线性有限元分析,模拟结果与试验结果吻合较好,在服役期间钢筋增强ECC梁的裂缝可以控制在0.4 mm以下.ECC材料的使用可明显提高梁的抗弯承载力、变形能力、延性等受弯性能.     

Behavior of preloaded RC beams strengthened with CFRP laminates

INTRODUCTION Externally bonded fiber reinforced polymer (FRP) composites can be used to improve the flexural strength of structural members. To evaluate the flex-ural performance of the strengthened members, it is necessary to study the flexural stiffness of FRP- strengthened RC members at different stages, such as pre-cracking, post-cracking and post-yielding. Up to now, only very few studies were focused on the structural members strengthened under pre-loading or pre-cracking (Arduin…     

Shear behavior of novel prestressed concrete beam subjected to monotonic and cyclic loading

Prestressed steel ultrahigh-strength reinforced concrete (PSURC) beam is a new type of prestressed concrete beam, which not only has a considerable compressive strength attributed to the ultrahigh strength concrete, but also ensures a certain degree of ductility at failure due to the existence of structural steel. Five of these beams were monotonically tested until shear failure to investigate the static shear performance including the failure pattern, load-deflection behavior, shear capacity, shear crack width and shear ductility. The experimental results show that these beams have superior shear capacity, crack control ability and shear ductility. To study the shear performance under repeated overloading, seven PSURC beams were loaded in cyclic test simultaneously. The overall shear performance of cycled beams is similar to that of uncycled beams at low load level but different at high load level. The shear capacity and crack control ability of cycled beams at high load level are reduced, whereas the shear ductility is improved. In addition, the influences of variables including the degree of prestress, stirrup ratio and load level on the shear performance of both uncycled and cycled beams were also discussed and compared, respectively.     

Shear Strength of Reinforced Concrete Beams Under Sea Water

The marine structures such as harbour,pier and inshore concrete terrace are exposed in adverse circumstances in a long period of time . Owing to the attack of external corrosive medium, their safety, durability and reliability decline. Especially the reinforced concrete(RC) structures in the wave splash area are more likely to be subjected to destruction and the loss is vast. Now the safety ,durability and reliability of structure have become increasingly an important subject to be studied. By way of the soaking and drying cycle test on the different mix proportions oblique section of 10 pieces of RC beams suffered artificial sea water(ASW) corrosion under 0,35,70,105,140 times of dry-wet cycles, the compared results of exerting pressure test of these beams under simply supporting were investigated. The law about the changes of the mechanical performance for RC beams with different mix proportions under different time periods for suffering corrosion of dry-wet cycles is as follows: the resistivity to ASW corrosion of the concrete specimens with various water cement ratio(various initial strength) is different ; the characters of oblique section failure for RC beams attacked by sea water are about the same as those for ordinary RC beam; along with the extension of the time for sea water attack, the bearing capacity for oblique section of RC beams varies wave upon wave. The specimens attacked by sea water for about 35 times of corrosion cycle achieve minimum bearing capacity.     

贝塞尔光束在湍流大气中传输的实验研究

高斯光束通过螺旋相位板和轴棱锥可获得高阶贝塞尔光束。在实验室模拟大气湍流并研究了贝塞尔光束在湍流大气中的传输特性。着重讨论了湍流扰动强弱及拓扑荷数变化对贝塞尔光束传输特性的影响。实验表明,湍流强弱及拓扑荷数变化都会影响贝塞尔光束的传输,大气湍流会降低贝塞尔光束的相干性。     

Flexural Behaviour of High－Strength Steel Fiber－Reinforced Concrete Beams

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玻璃纤维布加固的钢筋混凝土梁试验研究与抗弯承载力计算

对9根玻璃纤维布加固的钢筋混凝土梁和3根对比梁进行了抗弯性能试验研究. 试验中考虑了配筋率、加固量、剪跨比与混凝土强度等级4个参数. 试验结果表明, 经玻璃纤维布加固的钢筋混凝土梁抗弯承载力有显著提高; 混凝土强度、配筋率、加固量对极限荷载有显著影响; 剪跨比对加固梁的破坏形态有影响. 根据不同的破坏模式, 提出了抗弯承载力计算方法.     

Effect of corrosion on bond behavior and bending strength of reinforced concrete beams

There is growing concern for corrosion damage in reinforced concrete structures with several decades’ service. Pullout tests and beam tests were carried out to study the effect of reinforcement corrosion on the bond behavior and bending strength of reinforced concrete beams. The bond strength of plain bars and concrete initially increases with increasing corrosion, then declines. The turning point depends on the cracking of the concrete cover. The bond strength of deformed bars and concrete increases with corrosion up to a certain amount, but with progressive increase in corrosion, the bond strength decreases, and the cracking of the concrete cover seems to have no effect on the bond strength. On the basis of test data, the bond strength coefficient recommended here, which, together with the bond strength of uncorroded steel bars and concrete, can be used to easily calculate the bond strength of corroded steel bars and concrete. The bond strength coefficient proposed in this paper can be used to study the bond stress-slip relationship of corroded steel bars and concrete. The bending strength of corroded reinforced concrete beams declines with increasing reinforcement corrosion. Decreased bending strength of corroded RC beam is due to reduction in steel bar cross section, reduction of yield strength of steel bar, and reduction of bond capacity between steel bar and concrete. Project supported by Cao Guanbiao Key Technology Development Founding of Zhejiang University and Construction Ministry of China.     

GFRP加固混凝土梁受弯性能试验研究

对15根玻璃纤维布加固的钢筋混凝土梁进行了试验研究。试验结果表明,玻璃纤维布加固的钢筋混凝土梁抗弯承载力显著提高,加固效果明显,但要有足够的粘贴长度以避免发生剥离破坏。