【摘 要】
：
Considering the situation that fatigue life prediction of notched component is an indispensable part in the process of design in engineering,it is necessary to find some ways to solve such problems effectively.The stress and strain state of notched specim
【机 构】
：
School of Mechanical and Electronical Engineering,Lanzhou University of Technology,Lanzhou 730050,Ch
论文部分内容阅读
Considering the situation that fatigue life prediction of notched component is an indispensable part in the process of design in engineering,it is necessary to find some ways to solve such problems effectively.The stress and strain state of notched specimen is more complex,compared with smooth specimen.As a result,some researchers take advantage of the finite element method to analyze the mechanical properties of these kind of specimens,they can get the stress and strain state at the dangerous point directly instead of using theoretical methods.At the same time,the equation of shear stress is fitted by analyzing stress distribution of the section of notch root.The integral of shear stress in the section is equal to the external load,and the true stress value of notch root is derived.Then,the fatigue damage evolution equation of notched specimens under torsional load is proposed based on the closed-form solution in this paper.Meanwhile,the nonlinear fatigue life prediction model of notched specimens under the torsional load is given by using the damage mechanics theory.The proposed model is validated by experimental data (30CrMnSiNi2A steel and 45# steel).The results show that the predicted life is not only close to the experimental results,but also tends to be safe.The fatigue life of notched specimen is predicted by using notch geometric parameters and material constants.The model has more concise calculation process,avoids complicated fatigue tests,and facilitates engineering application.
其他文献
针对爬壁机器人在探测过程中,探测环境复杂且工业相机无法自动调焦等问题,设计了一种基于数字图像处理的工业相机自动调焦系统.通过在工业相机像距调节处添加精密传动机构与电机相连,并通过STM32控制电路控制步进电机调节.工业相机采集到的图片通过以太网传输至计算机,通过matlab利用图像质量评价函数对所采集到的图片进行函数计算,并结合搜索算法控制STM32改变调焦方向与步长,不断循环直至采集到最清晰的图像,从而完成自动调焦.
针对传统考试中心业务职能及其信息化建设现状分析,结合现代化信息技术最新应用,提出了一种智能化开放性自助式考试中心规划建设方案.首先,基于“人人可考、处处能考、时时可考”的教育考试现代化管理目标,设计了考试中心整体规划建设架构方案图;其次,从保障体系、技术运用、硬件支撑、软件设计四个方面详细阐述了方案建设途径;最后,针对考生作为主体如何主动完成整个考试流程进行了说明.智能化开放性自助式考试中心的建设,旨在从时间和空间上扩展考试管理功能及服务,提高教育考试现代化管理水平,创新教育考试管理模式,构建面向人人、终
针对水利设施混凝土裂缝难以检测的问题,基于深度学习模型,设计了一种针对混凝土裂缝自动检测系统.系统使用YOLO V5模型,首先,对已有的训练数据集进行增强;然后,将训练数据集经过backbone、neck提取到数据特征值;特征值经过识别器识别,获得损失函数;最后,通过反馈网络对模型参数进行训练.经过训练模型识别正确率达到0.96.系统在对混凝土裂缝检测测试中有较高的准确率,具有一定的实用价值.
Ultrasonic-assisted metal inert gas (U-MIG) welding experiments were performed to analyze the effect of Cu addition on the microstructure and mechanical properties of galvanized steel sheet welds,and first-principles calculations were undertaken to predic
The hot-stamped steel with ultrahigh strength is a promising material for the fabrication of automotive components.However,the coating on the sheet surface leads to a softening problem in the welded joint.Instead of the costly coating removal process,heat
This work presents a nonlinear finite element method to simulate the macroscopic mechanical re-sponses and the effects of martensite plasticity in a shape memory alloy (SMA) structure.A linear relationship formulation is adopted to express the influence o
Owing to the remarkable advantages in mechanical behavior,cast steel nodes have been widely used in static structures.Nowadays,cast steel nodes also gain increasing popularity due to the superior fatigue per-formance in dynamic structures,but they are not
The acceleration saltation of the traditional S-type acceleration model in the speed planning of the NURBS curve will result in the vibration and flexible impact of the machine tool.It will affect the surface quality of the components.The high speed smoot
Additional hysteretic experiments for corroded rectangular reinforced concrete (RC) columns with an axial load ratio of 0.27 were implemented.A quasi-static cyclic lateral loading with constant axial force was subjected to tests.Herein,a modified ductilit
Combined with fiber Bragg grating (FBG) sensing technology,four glass fiber reinforced polymer(GFRP) anti-floating anchors and four steel anti-floating anchors were tested for on-site destructive failure to investigate the anchoring performance and the bo