Lateral load-carrying capacity analyses of composite shear walls with double steel plates and filled concrete with binding bars

A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.

Shape design of the reinforcement for bending load-carrying capacity of under-matched butt joint under four-point bending load

To improve the bending load-carrying capacity （ BLCC） of under-matched butt joint under four-point bending load in the elastic stage, the shape design of the reinforcement is studied based on the theoretics of mechanics of materials. The concept, criterion, realization condition and design proposal of equal bending load-carrying capacity （EBLCC） are put forward. The theoretical analysis results have been verified by the finite element method. The simulation results are coincident basically with the ones of theoretical analysis. The research results show that the shape design of the reinforcement of EBLCC can improve BLCC of under-matched butt joint and the unilateral-side type reinforcement can replace double-side symmetry

Using a GIS to Assessment the Load-Carrying Capacity of Soil Case of Berhoum Area, Hodna Basin, (Eastern Algeria)

The concept of load-carrying capacity of the soil can be evaluated by two main components: permissible stress and permissible depth;and therefore, running it begins its assessment that allows an outline of exploitation. Nevertheless, the assessment of the load-carrying capacity made the object of several works of research and many models, based on the multi-criteria analysis, have been established. This work examines the contribution of GIS approach to assessment load-carrying capacity of the soil. This one has been finished in two practicums: 1) Assessment of the capacity of soil by a multi-criteria approach, using the Weighted Sum Model (WSM);2) It brought to use the GIS approach to evaluate and spatialize degree of soil bearing stresses resulting from the buildings, as well as load distribution. The method has been applied to the Berhoum area of Hodna Basin, in eastern Algeria, where each is characterized by its various natural properties and density of equipment. Final results are better in the classification of the degree of load-carrying capacity possible in each site. This results in allowing exploiters to program their optimal designs for the rational management of the area.

Boundary slippage for generating hydrodynamic load-carrying capacity

Boundary slippage is used to generate the load-carrying capacity of the hydrodynamic contact between two parallel plane surfaces. In the fluid inlet zone, the fluidcontact interfacial shear strength on a stationary surface is set at low to generate boundary slippage there, while in the fluid outlet zone the fluid-contact interfacial shear strength on the stationary surface is set at high enough to prevent the occurrence of boundary slippage. The fluid-contact interfacial shear strength on the entire moving surface is set at high enough to prevent boundary slippage on the moving surface. These hydrodynamic contact configurations are analyzed to generate the pronounced load-carrying capacity. The optimum ratio of the outlet zone width to the inlet zone width for the maximum load-carrying capacity of the whole contact is found to be 0.5.

A Discusion on Limited Load-Carrying Capacity of Rectangular Plates

The elastic-plastic method is often used in designing the inner flat bulkhead plates of submarines, and the upper structure of ships and drilling platforms. Such bulkhead plates can bear the load only once. For the improvement of the load-carrying capacity or the reduction of the weight of plates, the yield line analytical method is employed in this paper to design the bulkhead plate to improve economy and increase the effiective load. Besides, a further sutdy of this method has been made theoretically and experimentally, and the data of the limited load-carrying capacity of the plate have been obtained. Furthermore, the safety coefficients for such a method are presented, which can be used as reference for related departments and staffs.

Impact of the thermal effect on the load-carrying capacity of a slipper pair for an aviation axial-piston pump

A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity.At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5.

A novel efficient energy absorber with free inversion of a metal foam-filled circular tube

In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with the results of the finite element(FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption(SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone.

Load-carrying capacity and practical calculation method for hollow cylinder joints connected with H-shaped beams

A type of hollow cylinder joints connected with H-shaped beams is proposed for spatial structures. Based on von Mises yield criterion and perfect elasto-plasticity model, a series of finite element models of the joints is established, in which the effect of geometric nonlinearity is taken into account. Then mechanical behavior and load-carrying capacity of the joints were investigated, which were subjected to axial load, in- and out-plane bending moments, and their combinations. The results show that the ultimate loads of the joints are determined by the maximum displacement. Furthermore, the case of one joint connected with multiple beams was discussed. Experiments on a set of typical full-scale joints were conducted to understand the structural behavior and the failure mechanism of joint, and also to validate the finite element models. Finally, the practical calculation method was established through finite elements analysis (FEA) results and numerical fitting. The results show that the joints are more ductile and materially economical than welded hollow spherical joints, and the practical calculation method can provide a reference for direct design and the revision of relevant design codes.

Prediction of the load-carrying capacity of reinforced concrete connections under post-earthquake fire

Finding out the most effective parameters relating to the resistance of reinforced concrete connections(RCCs)is an important topic in structural engineering.In this study,first,a finite element(FE)model is developed for simulating the performance of RCCs under post-earthquake fire(PEF).Then surrogate models,including multiple linear regression(MLR),multiple natural logarithm(Ln)equation regression(MLn ER),gene expression programming(GEP),and an ensemble model,are used to predict the remaining load-carrying capacity of an RCC under PEF.The statistical parameters,error terms,and a novel statistical table are used to evaluate and compare the accuracy of each surrogate model.According to the results,the ratio of the longitudinal reinforcement bars of the column(RLC)has a significant effect on the resistance of an RCC under PEF.Increasing the value of this parameter from 1%to 8%can increase the residual load-carrying capacity of an RCC under PEF by 492.2%when the RCC is exposed to fire at a temperature of 1000°C.Moreover,based on the results,the ensemble model can predict the residual load-carrying capacity with suitable accuracy.A safety factor of 1.55 should be applied to the results obtained from the ensemble model.

非对称齿廓渐开线齿轮传动的热分析

探讨了非对称齿轮摩擦热流量的计算方法并分析了其沿啮合面的分布规律以及相关的影响因素,推导了轮齿本体温度的热平衡方程,建立了轮齿有限元温度分析的模型。结果表明:达到热平衡时,非对称齿轮本体温度最大值比对称齿轮低,因而双压力角非对称齿轮能有效提高轮齿齿面抗胶合承载能力,并分析了压力角与齿面温度峰值的关系。

基于闪温法的传动齿轮抗胶合可靠度分析与计算

以Block闪温法为基础 ,论述了齿轮传动抗胶合可靠性分析模型和计算方法 ,并用实例加以说明 ,为探索可靠性技术在齿轮抗胶合承载能力计算中的应用进行了有益的尝试。

齿轮热胶合承载能力数值计算方法研究

建立了时域内高速重载齿轮系统热平衡状态分析模型,推导了齿面温升公式,通过数值计算方法得到了接触点温度随时间的变化规律以及闪温沿啮合线的分布规律.建立了符合实际工况的热弹流理论分析模型,将本体温度作为初始温度进行求解,以界面最高温升作为接触点闪温,得到了接触点的温度场、闪温以及沿啮合线的闪温分布,获得了沿啮合线的膜厚比,最后综合比较分析了Blok理论和热弹流理论.结果表明:文中两种数值方法所求闪温与Blok闪温十分接近,热弹流法从理论上来讲更符合实际情况.热弹流计算结果可以同时得到齿面闪温和油膜厚度等参数,为热胶合强度设计和校核提供更多的信息.

蜗轮蜗杆油胶合承载能力试验研究

通过进行大量的台架评定探索性试验 ,研究开发出蜗轮蜗杆油胶合承载能力台架评定试验方法 ,对蜗杆传动的摩擦学设计及新型润滑油的开发具有实际指导意义。

动车组用齿轮润滑油抗胶合性能对比试验研究

针对可供动车组使用的4种润滑油——进口润滑油A、B、C和国产润滑油D,通过试验研究了行驶里程数对进口润滑油A和B的抗胶合性能的影响,为制定合理的油品换油周期提供了参考;并研究了4种润滑油的抗胶合性能,比较了它们的优劣。该研究对于促进铁路运输事业的发展有重要意义。

高速齿轮传动CAD系统中胶合承载能力模块的实现

根据国家标准GB/Z6431.2-2003胶合承载能力计算方法将高速齿轮设计过程中胶合承载能力校核计算实现程序化并添加到高速齿轮传动CAD系统中,在高速齿轮传动设计中,只需输入和选择一定数量的已知数据就可以迅速、准确地进行胶合承载能力计算,提高了高速齿轮传动CAD系统中的设计可靠性。重点探讨了数据库的建立、计算机程序的编制。通过计算实例讨论了所提及方法的效率。

混合润滑下螺旋锥齿轮抗胶合能力分析

针对螺旋锥齿轮重载下热胶合失效问题,对螺旋锥齿轮在混合润滑条件下的摩擦热行为进行分析.通过混合弹流润滑数值计算方法和基于有限元的热分析方法,综合考虑螺旋锥齿轮的表面粗糙度、载荷分担、速度矢量和真实接触几何等因素建立点接触混合润滑分析模型,计算啮合轨迹上的连续摩擦系数变化和摩擦热流率,采用有限元分析软件进行齿面热载荷的加载,考虑轮齿导热和齿面与环境的热对流,分析轮齿本体温度场分布和啮合过程中闪温变化.根据齿面最大接触温度与国际标准ISO 6336-20中齿轮抗胶合能力计算方法进行比较分析.结果表明:有限元热分析得到的齿面温度与ISO所得变化规律十分接近,其最大温度低于ISO标准计算温度,使用ISO标准计算出螺旋锥齿轮抗胶合安全系数小于有限元法.在混合润滑下求解的齿面热流率和温度变化,并且考虑了齿轮热传导和热对流影响,从理论上来说有限元法更加符合实际工作情况. ISO方法在处理上述问题以及计算本体温度上仍有不足,但其在齿轮抗胶合能力校核上具有广泛的适用性,可考虑结合有限元热分析法解决传热问题同时进行抗胶合能力综合评价.

齿轮弯曲强度与胶合强度的二次优化法

本文提出了一种多目标函数的优化方法,即二次优化法,并且用之求解了齿轮在胶合强度与弯曲强度条件下的综合最佳变位系数。

EFFECTS OF MANUFACTURING ERRORS ON GAS LUBRICATED JOURNAL BEARING WITH COMPLIANT SURFACE

A theoretical study has been performed to investigate the influence of manufacturing errors on the bearing housing of a gas lubricated journal bearing with compliant surface I in particular on the bearing load capacity. A gas film thickness distribution is presented, in which errors o f both circumferential and axial bearing housing are considered. The influence of the errors on bearing performance is compared between rigid and compliant surface bearings. It was shown that the compliant surface bearings are less sensitive to the manufacturing errors than the rigid surface bearings. Thelefore, the cost of compliant surface bearing could be reduced by setting a larger manufacturing error tolerance.

Experimental Evaluation of the Post-ultimate Strength Behavior of a Ship＇s Hull Girder in Waves

Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are presented.The experiment was performed using a scaled model in a tank.In the middle of the scaled model,sacrificial specimens with circular pillar and trough shapes which respectively show different bending moment-displacement characteristics were mounted to compare the dynamic collapse characteristics of the hull girder in waves.The specimens were designed by using finite element(FE)-analysis.Prior to the tank tests,static four-point-bending tests were conducted to detect the load-carrying capacity of the hull girder.It was shown that the load-carrying capacity of a ship including reduction of the capacity after the ultimate strength can be reproduced experimentally by employing the trough type specimens.Tank tests using these specimens were performed under a focused wave in which the hull girder collapses under once and repetitive focused waves.It was shown from the multiple collapse tests that the increase rate of collapse becomes higher once the load-carrying capacity enters the reduction path while the increase rate is lower before reaching the ultimate strength.

Numerical Analysis on Nanoparticles-laden Gas Film Thrust Bearing

Nanoparticles can be taken as additives and added into various fluids to improve their lubricating performances. At present, researches in this area are mainly concentrated on the improvement effects of nanoparticles on the lubricating performances of liquid such as oil and water. Nanoparticles will also affect gas lubrication, but few related studies have been reported. Nanoparticles-laden gas film (NLGF) is formed when adding nanoparticles into gas bearing. Then, the lubricating performances of gas bearing including pressure distribution and load-carrying capacity will change. The variations of pressure distribution and load-carrying capacity in nanoparticles-laden gas film thrust bearing are investigated by numerical method. Taking account of the compressibility of gas and the interactions between gas and nanoparticles, a computational fluid dynamics model based on Navier-Stokes equations is applied to simulate the NLGF flow. The effects of inlet nanoparticles volume fraction and orifice radius on film pressure distribution and load-carrying capacity of the NLGF are calculated. The numerical calculation results show that both of the film land pressure and the maximum film pressure both increase when the nanoparticles are added into gas bearing, and the film pressures increase with the rising of the inlet nanoparticles volume fraction. The nanoparticles have an enhancement effect on load-carrying capacity of the studied bearing, and the enhancement effect becomes greater as the film thickness decrease. Therefore, nanoparticles can effectively improve the lubricating performance of gas bearing. The proposed research provides a theoretical basis for the design of new-type nanoparticles-laden gas film bearings.