共查询到20条相似文献，搜索用时 218 毫秒
1.
《东南大学学报》2021,(1)
运用外推缺口应力法研究了铸钢节点环形对接焊缝的疲劳寿命.首先分析了焊接铸钢节点有限元模型的网格敏感性以确定最优网格尺寸.基于焊接铸钢节点有限元模型焊趾和焊根处的应力场分析,使用外推缺口应力法的sharp模型推导有效缺口应力法rounded模型的有效缺口应力,其关键问题是计算外推点C,而参数C与焊接铸钢节点的几何参数之间具有指数函数关系.通过设置不同的几何参数值,确定相应的C值,通过多元线性回归分析可得到外推点C与几何参数之间的函数关系.最后,基于有效缺口应力疲劳参量,根据IIW规范评估了典型铸钢节点环形对接焊缝的疲劳寿命.研究结果表明,外推缺口应力法有效地简化了有效缺口应力的计算过程,同时可准确地评估铸钢节点环形对接焊缝的疲劳设计寿命. 相似文献
2.
《实验室研究与探索》2013,(12)
对低碳钢材料带孔薄壁圆管试样采用逐级加载试验方法,得出其在室温下的单轴循环应力-应变本构关系。利用有限单元法对圆管试样进行弹塑性分析,采用Von Mises屈服准则、多线性随动强化模型,并结合试验获得的本构关系来定义材料的弹塑性特性。拉扭应变载荷加载在柱坐标下进行,采用一端固定,另一端加轴向位移与周向位移的方式。分别在纯拉、纯扭以及拉-扭比例加载下计算出应力应变场,获得不同受力情况下不同孔径尺寸试样在缺口处的应力应变分布。计算结果为多轴加载疲劳试验和复杂应力状态下工程零部件的疲劳寿命预测与分析提供基本数据。 相似文献
3.
基于ABAQUS有限元分析方法,对两种热处理工艺下的16 Mn钢中MnS夹杂物在同一拉伸载荷作用下的应力和应变分布进行了研究。结果表明,两种晶粒尺寸的材料在长条形MnS夹杂物附近存在着垂直于加载方向的X形状的Mi-ses应力和PEEQ集中区。但细晶的16Mn钢中MnS引起的应力和应变集中程度要明显大于粗晶的16Mn钢中MnS引起的应力和应变集中,其原因与细晶强化有关。 相似文献
4.
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196.2MPa,超常载荷工况下构架的最大应力为307.6MPa,均小于构架主材料SMA490BW型耐候钢的许用应力。在超常载荷工况下进行结构优化分析,分别设定侧梁上下盖板和内外侧板的厚度为设计变量、最大等效应力为约束条件、构架最小质量为目标函数。优化结果表明:优化后构架总质量减少109 kg,较优化前降低6.8%;构架最大等效应力为329.98 MPa,仍满足其强度要求。对构架结构参数的优化可有效降低SKMB-200型转向架的簧下质量,进而提升其动力学性能,可为动车组转向架结构优化提供参考。 相似文献
5.
采用有限元分析软件ANSYS8．0对铸铁机链板进行了静力分析和敏感度分析,获得了在载荷作用下结构的应力、应变值和影响应力变化的敏感参数,为结构的优化设计选择设计变量提供了依据。并对结构进行了优化设计,达到了合理而又经济的使用材料之目的。 相似文献
6.
《西安文理学院学报》2016,(2)
减振器座是车身结构重要部分之一,主要承受来自悬架系统的垂向载荷.对某车型在路试工况中后减振器座发生了轻微裂纹为研究对象,而后期提升整车综合性能需降低减振器阻尼系数,分析路试中减振器阻尼系数,车辆配重参数对减振器座疲劳寿命的影响.结合CAE将减振器座模型加载上跳工况获得载荷大小做静力学分析,计算应力载荷分布并确定应力敏感点.通过应变计获得不同减振器阻尼和车辆配重下的道路载荷谱,确定减振器座开裂原因,并提出在减振器座上增加加强筋改进方案.最后经过路试工况验证,使用效能可靠. 相似文献
7.
《新课程实验教材小一数学教案设计合订本》2003,(2):14-15
结合某工程深基坑边墙单孔复合型锚杆施工，选取4根锚杆作为试验锚杆，通过在锚固体范围埋设多个应变测试元件，对锚固体在不同张拉载荷条件下的应力分布状态进行了现场测试研究。根据单孔复合型锚杆的结构特点，对代表性锚固体建立有限元数值模型，并对锚固体的应力．应变特征进行了数值分析。根据现场测试和数值分析结果，对单孔复合型锚杆锚固体的应力分布规律和锚固机理进行了研究。 相似文献
8.
文章以某轻型货车驱动桥为基础,运用Solidworks软件建立前梁、转向节、转向摇臂等部件三维模型并对其进行优化,采用Solidworks三维软件simulation插件对前梁和转向节建立有限元模型,并对前梁和转向节在紧急制动工况和侧滑工况下施加载荷作用,得到各工况下的应力、应变和位移云图。结果表明：该前桥既满足强度和刚度要求,同时又具有良好的驾控性能。 相似文献
9.
利用分离式Hopkinson压杆(SHPB)研究了GFPP玻璃钢的在不同应变率下的力学响应,通过其动态的应力应变曲线发现,其属于一种典型的粘弹性材料,具有明显的应变率敏感性。在冲击载荷作用下,GFPP玻璃钢表现出明显的各向异性,分析认为:其各向异性除了与纤维的排列和铺层等有关外,材料中的微裂纹和空洞等损伤的发展演化也会导致各向异性。损伤的发展演化将导致材料的软化和破坏;并且损伤的发展演化除了与应变有关,还与应变率有关。本文还阐明了这种材料在两个相互垂直加载方向上的应变率效应,对这两个方向在不同加载条件下的破坏机制进行了分析。 相似文献
10.
分析了节点各杆最不利受力状况试验结果，测试了各杆在最不利荷栽作用下的应力状况，揭示了节点的受力性能，为3K形钢管节点的应用提供准确的试验数据。 相似文献
11.
利用BIM技术成功解决了在建筑物体混凝土结构向钢结构转换处转换层梁柱节点的钢筋排布和下料优化问题。通过BIM软件建立的节点三维模型,对节点进行二次深化设计,并将设计结果进行可视化交底。此技术缩短了节点深化的时间,简化了技术交底流程,保证了节点施工质量,节约了钢筋等原材料,减少了节点施工工期。 相似文献
12.
Jing-qing Liu Zhi-feng Luo Ke Liu Yi-fu Zhang Hong-xi Peng Bao-lan Hu Hong-xing Ren Xiao-yan Zhou Shang-de Qiu Xiao-fang He Ping Ye Hamid Bastani Li-ping Lou 《浙江大学学报(A卷英文版)》2017,18(4):313-328
Biofilm detachment caused by flushing can result in secondary contamination in drinking water distribution systems (DWDSs). To evaluate the impact of flushing on biofilm detachment, actual water supply pipes including ductile cast iron pipes (DCIPs), gray cast iron pipes (GCIPs), and stainless steel compound pipes (SSCPs) were used in this study. Real-time quantitative polymerase chain reaction and 454 pyrosequencing were used to quantify bacteria and analyse microbial community composition, respectively. The results showed that the pipe material greatly influences the resistance of a biofilm to flushing. Biofilms attached to DCIPs were able to resist quite strong flushing, while those attached to GCIPs and SSCPs were sensitive to flushing. Both flush-resistant and flush-sensitive bacteria were present in all the biofilms, but their frequency differed among the different metal pipes. Thus, the resistance to flushing of bacteria is related not only to the nature of the bacteria, but also to the pipe material. Although flushing can remove some of the biofilm and may be a good way to clean the DWDS, the shear stress needed to remove the biofilm differs among different pipe types. The results of this study provide technical support for the management and operation of DWDS. 相似文献
13.
随着钢结构的发展,钢管搭接节点应用越来越广泛.钢结构中节点受力最复杂,目前对平面K型钢管搭接节点的静力研究有很好的基础.但是在低周往复荷载下节点滞回性能的分析还比较少.采用有限元法对平面K型圆钢管搭接节点在弦杆轴向荷载作用下节点的承载力进行研究,对比分析不同几何参数与节点焊接形式下的极限承载力和破坏形式. 相似文献
14.
In this paper, based on the principle of heat transfer and thermal elastic-plastic theory, the heat treatment process optimization scheme for face gears is proposed according to the structural characteristics of the face gear and material properties of 12Cr2Ni4 steel. To simulate the effect of carburizing and quenching process on tooth deformation and residual stress distribution, a heat treatment analysis model of face gears is established, and the microstructure, stress and deformation of face gear teeth changing with time are analyzed. The simulation results show that face gear tooth hardness increases, tooth surface residual compressive stress increases and tooth deformation decreases after heat treatment process optimization. It is beneficial to improving the fatigue strength and performance of face gears. 相似文献
15.
该文针对小麦抗倒伏的问题,分别将小麦茎秆按刚/弹性材料处理,通过微元法思想分别计算出各个节点处最大弯应力及安全应力,得出麦秆折断的条件是:实际弯应力与临界弯应力最接近的那个节点,从而建立了小麦茎秆抗倒伏的数学模型。最后应用该模型对2007年数据中腊熟期各品种的抗倒伏风速进行了计算。 相似文献
16.
Improving the Fatigue Performance of the Welded Joints of Ultra-Fine Grain Steel by Ultrasonic Peening 总被引：2，自引：0，他引：2
Contrast tests were carried out to study the fatigue performance of the butt joints treated by ultrasonic peening, aiming at the improvement of ultrasonic peening treatment(UPT) on welded joints of a new material. The material is a new generation of fine grain and high purity SS400 steel that has the same ingredients as the traditional low carbon steel. The specimens are in two different states:welded and ultrasonic peening conditions. The corresponding fatigue testing data were analyzed according to the regulation of the statistical method for fatigue life of the welded joints established by International Institute of Welding(IIW). Welding residual stress was considered in two different ways: the constant stress ratio R = 0.5 and the Ohta method. The nominalstress-number (σ-N) curves were corrected because of the different plate thickness compared to the standard and because there was no mismatch or angular deformation. The results indicated that: 1 ) Compared with the welded specimens, when the stress range was 200 MPa, the fatigue life of the SS400 steel specimens treated by ultrasonic peening is prolonged by over 58 times, and the fatigue strength FAT corresponding to 106 cycles is increased by about 66％; 2) As for the SS400 butt joint ( single side welding double sides molding) , after being treated by UPT, the nominal S-N curve (m = 10) of FAT 100 MPa(R =0.5) should be used for fatigue design. The standard S-N curves of FAT 100 MPa (R = 0.5, m = 10) could be used for fatigue design of the SS400 steel butt joints treated by ultrasonic peening. 相似文献
17.
对调质42CrMo钢进行室温下各种应力循环和对称应变循环的低周疲劳实验,揭示材料的循环软化特性,棘轮变形和低周疲劳特性以及棘轮-疲劳交互作用。结果表明,调质42CrMo钢体现出明显的循环软化;在应力幅值或平均应力较高时,试样的棘轮变形较大,其破坏形式为延性破坏,而在应力水平较低时,材料的破坏由疲劳裂纹扩展所致的脆性断裂引起;材料在应力循环下的低周疲劳寿命由于有棘轮变形的产生而受到平均应力、应力幅值、最大应力和应变比等多种因素的影响。 相似文献
18.
苑敏 《邢台职业技术学院学报》2012,(5):73-77
站台雨棚钢结构工程焊接质量要求较高,以宁杭铁路湖州南站钢结构焊接为例,阐述了其焊接形式与工具的选择、焊接中质量监控方法及质量缺陷的处理措施,并给出了特殊气候条件下焊接作业的具体做法,为同类型工程施工提供了参考。 相似文献
19.
The growth and evolution of the knowledge network in supply chain can be characterized by dynamic growth clustering and non-homogeneous degree distribution.The networks with the above characteristics are also known as scale-free networks.In this paper,the knowledge network model in supply chain is established,in which the preferential attachment mechanism based on the node strength is adopted to simulate the growth and evolution of the network.The nodes in the network have a certain preference in the choice of a knowledge partner.On the basis of the network model,the robustness of the three network models based on different preferential attachment strategies is investigated.The robustness is also referred to as tolerances when the nodes are subjected to random destruction and malicious damage.The simulation results of this study show that the improved network has higher connectivity and stability. 相似文献
20.
The key in the force transmission between the tower and the foundation for offshore wind turbines is to transfer the large moment and horizontal loads.The finite element model of a large-scale prestres... 相似文献