Adhesion failure propagation in adhesively-bonded single-lap laminated FRP composite joints

This paper deals with three-dimensional non-linear finite element analyses to study the behaviour of embedded adhesion failure propagation in adhesively-bonded single-lap laminated FRP composite joints clamped at one end and subjected to uniform extension at the other end. Because of loading eccentricity and joint material heterogeneity, the embedded adhesion failure is likely to initiate from the stress singularity points and will propagate from either end of the adhesive layer along the adherend–adhesive interfaces. The effects of interaction of such failures and their propagations along the interfaces of the adherends and adhesive are the main concerns of this paper. The peel and shear stresses have been computed along the mid-surface of the adhesive layer for varying adhesion failure lengths to find out the influence of adhesion failure length on the strength of the joint being analyzed. The concept of fracture mechanics has been used to calculate the strain energy release rate (SERR) as the adhesion failure propagates using the virtual crack closure technique (VCCT). It is seen that mode-II SERR is predominant in the propagation of such adhesion failures. The SERR values computed with respect to the adhesion failure lengths being propagated from the two ends of the adhesive layer are seen to be different.     

Three-Dimensional Finite Element Analysis of the Stress Distribution in Bi-Adhesive Bonded Joints

A 3-D elastic finite element model was developed to investigate the stresses distribution of bi-adhesive bonded joints (i.e., the bond line of joints filled with two adhesives of dissimilar toughness). The effects of the loading mode on the stress distribution of joints, including the single-lap joints under tensile loading (i.e., single-lap joints) and the butt joints under cleavage loading (i.e., cleavage joints), were also studied in detail. Results showed that higher stress, distributed at the contact position of the dissimilar adhesives placed along the bond line of bi-adhesive bonded joints. Also, the maximum stress of the adhesive layer decreased when the length ratios and bonding sequence along the bond line, filled with two dissimilar adhesives, was appropriately designed. At the same time, stress convergence in the adhesive layer of bi-adhesive joints was also obviously reduced in contrast to the mono-adhesive joints. The numerical investigation shows that it is necessary to take into account the change of loading modes when optimizing the bi-adhesive joint design, because of the uneven and complex loading modes of the adhesive bonding structure in the engineering applications.     

抽油机井油管接头有限元分析与寿命预测

对油管接头进行了在循环拉伸载荷作用下的弹塑性接触有限元分析 ,给出油管接头在循环载荷作用下所表现出的力学特性 ,特别是应力应变集中部位 (第 1啮合齿齿根 )的应力应变循环规律以及应力应变幅。采用局部应力应变分析法 ,对油管接头进行疲劳寿命的预测 ,证明J5 5材料、公称锥度上扣 1.5、1.75和 2圈的油管接头在循环拉伸载荷 6 0～ 12 0kN作用下 ,疲劳裂纹萌生期的寿命都达到了 3年以上     

双金属复合管的弹塑性分析及有限元模拟

根据双金属复合管的一次胀压成形原理,对假设内管为线性强化材料模型、外管为理想弹性材料模型的复合管进行了弹塑性分析计算,得出胀合压力与内外管之间残余接触压力的计算式,并利用Ansys进行有限元模拟分析.结果表明,该模型的理论预测与仿真结果基本一致,且得到复合管仿真成形曲线与胀合成形原理基本统一.     

带长矩形接管受压圆简体的有限元分析与强度计算

本文运用有限元软件FEPG,建立了带长矩形接管受压圆筒体的三维参数化有限元模型,研究了矩形接管部位的应力分布特点,按照分析设计规范对带长矩形接管受压圆筒体进行了强度评定,并针对应力分布的不合理性提出了结构改进措施。     

基于有限元分析的CNG储气井疲劳设计计算

采用有限元方法对储气井危险部位——套管与管箍螺纹连接段进行分析,应用ANSYS软件计算,获得了该部位详尽的应力场。通过经验公式和理论推导给出了交变应力幅S与疲劳寿命N的解析表达式。在此基础上,进行了一系列的修正和安全系数的设定,最终获得了CNG储气井的疲劳设计曲线,最后,给出了考虑疲劳累积损伤问题的方法和设计依据。     

底部减薄三通管件塑性极限内压的有限元分析

采用有限元分析研究了单一内压作用时局部减薄缺陷对三通管塑性极限内压的影响。总结出含底部缺陷三通管的塑性极限载荷随缺陷尺寸影响的变化规律。     

催化裂化装置烟机入口管线及其法兰接头失效的有限元分析及优化设计

针对催化裂化装置烟气管道的某些法兰接头发生泄漏失效的现状,为分析其失效原因,对烟气管道与失效的法兰接头进行了有限元计算与分析,并提出了改进措施。     

1Cr18Ni9Ti波纹管膨胀节失效分析及改进

本文主要根据１Ｃｒ１８Ｎｉ９Ｔｉ波纹管膨胀节在催化车间烟道上的使用情况,分析其失效的机理,并改用Ｂ－３１５钢波纹管膨胀节代替的使用情况及其经济效益。     

玄武岩纤维增强塑料筋混凝土梁受弯破坏形态有限元分析

设计并制作了3根新型的玄武岩纤维增强塑料筋（BFRP筋）增强混凝土梁,并对其进行三分点加载试验和有限元分析。结果表明,BFRP筋混凝土梁的受弯破坏形态有别于传统的钢筋混凝土梁,其破坏截面均位于加载点附近。梁内的销栓作用对BFRP筋的受力非常不利;较大的裂缝宽度不仅会影响到BFRP筋混凝土梁的正常使用,还会影响到梁的受弯破坏形态;BFRP筋突出的表面变形特征、较低的横向抗剪强度和弹性模量等对上述破坏形态的发生有着重要影响;加载点处BFRP筋混凝土较为严重的局部黏结破坏、较大的销栓作用、应力集中效应和较大的裂缝宽度等使BFRP筋处于复杂的不利受力状态,这是造成上述破坏形态的主要原因。     

加压转鼓过滤机的设计及有限元分析

基于压力环境可以大幅度提高过滤的推动力,以及在单台过滤机上连续完成悬浮液过滤、滤饼洗涤、滤饼干燥、滤饼卸料和滤网清洗等工序的设计思想,提出新型加压转鼓过滤机的机械设计方案。使用有限元分析法对复杂载荷作用下的过滤机内转鼓、外鼓进行强度和刚度的校核。     

O形环膨胀节的设计与有限元分析

介绍了O形环膨胀节的结构设计 ,并对已运行的两台换热器上的膨胀节进行了有限元法分析 ,为进一步搞好膨胀节安全可靠的设计奠定了基础     

矩形容器椭圆形开孔接管区强度有限元分析及轻量化设计

根据有限元分析设计的原则,以受内压的方形容器开椭圆形孔为课题,对不同外力和力矩作用下开椭圆孔的方形容器接管区进行了应力分析、强度设计和疲劳分析,并提出了轻量化优化设计方案,使容器的整体质量减少了22.3%。     

基于ANSYS换热器法兰有限元分析及应力评定

为了换热器在运行过程中,法兰结构安全。利用ANSYS有限元分析软件,对换热器壳体法兰在机械载荷和温度载荷共同作用下的应力强度进行了分析,并对其危险截面做了应力评定和强度校核。对壳体法兰不同危险部位进行分析与评定并且合格,这样才能保证其安全可靠地运行。     

Structural Design and Finite Element Simulation Analysis of Grade 3 Graded Porous Titanium Implant

The metal titanium is often used as a dental implant material, and the elastic modulus of solid titanium implants does not match the biological bone tissue, which can easily produce a stress shielding effect and cause implant failure. In this paper, a three-level gradient porous structure implant was designed, and its mechanical and biological adaptability were studied by finite element simulation analysis. Combined with the comprehensive evaluation of the mechanical and biological properties of implants of various structures, the analysis found that a porous implant with porosity of 59.86% of the gradient was the best structure. The maximum equivalent stress of this structure in the mandible that simulated the oral environment was 154.34 MPa, which was less than half of its theoretical compression yield strength. The strain of the surrounding bone tissue lies in the bone compared with other structures, the proportion of the active state of plastic construction is larger, at 10.51%, and the fretting value of this structure and the bone tissue interface is the smallest, at only 10 μm.     

催化裂化装置烟机入口管线及其膨胀节事故失效分析有限元计算

针对某公司重油催化裂化装置能量回收系统中烟机入口管线上,相继发生管道、法兰、阀门等焊缝处断裂、摆式支架失衡及膨胀节断裂等失效事故,对该段管线及失效的膨胀节进行了有限元计算与分析,且提出了改进措施和建议。     

带加强筋的储罐罐顶稳定性和强度有限元分析

使用ANSYS有限元软件对带加强筋的储罐罐顶结构进行建模,分别进行了外部载荷作用下的线性屈曲分析和内部载荷作用下的强度分析,并根据相应的标准对结构的安全性进行了评价。分析表明:加强筋结构较为合理,方案能够满足稳定性和强度需求。     

不同结构纺织复合材料准静态侵彻实验分析及有限元模拟

本文研究了两种不同结构三维结构纺织复合材料——三维正交机织玻璃纤维,不饱和树脂复合材料和双轴向纬编针织玻璃纤维／不饱和树脂复合材料在MTS材料试验机上的准静态侵彻测试。以纯铝MTS实验数据为标定,分析了准静态侵彻载荷一位移曲线及其破坏机理,比较了不同结构纺织复合材料以及纯铝的位移一载荷曲线,由此计算得到位移与吸能关系曲线。同时根据复合材料各自织物中纤维束排列及织物成型特点,分别建立了复合材料的细观结构模型和单胞模型。编写用户子程序（VUMAT）,用ABAQUS软件进行了有限元模拟。结果表明：三维纺织复合材料各自损伤结果和载荷-位移曲线与实验结果吻合较好,证明有限元的有效性。三维正交结构复合材料抗侵彻能力优于双轴向纬编针织复合材料,但是破坏过程中其抗侵彻能力幅值变化差异大,没有针织复合材料抗侵彻能力稳定。     

Free Vibration Analysis and Design of an Adhesively Bonded Corner Joint with Double Support

This study carries out the three dimensional free vibration analysis of an adhesively bonded corner joint and investigates the effect of an additional horizontal support to the adhesive corner joint with single support on the first ten natural frequencies and mode shapes. In the presence of a horizontal support the effects of the vertical support length, the adhesive thickness, the plate thickness, and the joint length on the natural frequencies and modal strain energies of the adhesive joint were also investigated using the back-propagation Artificial Neural Network (ANN) method and the finite element method. The natural frequencies and modal strain energies increased with increasing plate thickness, whereas an adverse effect was observed for increasing joint length. Both horizontal and vertical support lengths exhibited similar effects but the adhesive thickness had a negligible effect. The plate thickness and the joint length are dominant geometrical parameters in comparison with both horizontal and vertical support lengths. The proposed ANN models were combined with the Genetic Algorithm in order to determine the optimal corner joint in which the maximum natural frequency and minimum elastic modal strain energy are achieved for each natural frequency and mode shape of the adhesive corner joint and the optimal dimensions were given versus one geometrical parameter.     

带复杂花纹的子午线轮胎稳态滚动的有限元分析及沟裂问题的探讨

以子午线轮胎215/75R17.5为例,考虑轮胎变形的几何非线性、材料非线性以及轮胎与地面、轮胎与轮辋的大变形非线性接触等,并考虑复杂胎面花纹,利用ABAQUS软件建立轮胎与地面接触的三维有限元模型。对带复杂胎面花纹的子午线轮胎进行了静负荷工况、和稳态滚动工况的模拟,同时将分析结果与仅带纵向沟槽的轮胎进行了对比,并对轮胎沟裂问题进行了探讨。