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991.
根据粘钢加固钢筋混凝土梁各种组成材料的布置特点,选用分离式模型,建立了粘钢加固梁的有限元模型。利用建立的模型对同一钢筋混凝土梁在粘贴钢板量相同的情况下,采用不同层数粘贴的加固梁进行了分析。通过有限元分析发现,在相同荷载作用下,粘贴1层钢板梁的挠度及钢筋和混凝土的应力最大,粘3层次之,粘2层最小。这表明多层加固的效果优于单层加固,但加固层数不宜太多,这些结果与理论分析结果相吻合,这说明该模型对未开裂粘钢加固钢筋混凝土梁是适用的。 相似文献
992.
993.
复合材料广泛应用于航空航天领域,其可靠性、稳定性及承载能力等对于航空设备尤为重要.以复合材料加筋板作为研究对象,对其材料属性和几何参数进行灵敏度分析.首先,基于ABAQUS软件建立复合材料加筋板的有限元模型,对轴向压缩载荷下的屈曲载荷进行了研究;其次,针对加筋板结构的复杂性,基于Kriging方法的代理模型建立复合材料加筋板屈曲载荷与材料属性和几何参数之间的函数关系;最后,采用Sobol全局灵敏度分析法求解复合材料加筋板材料属性和几何参数的灵敏度.研究结果为复合材料加筋板可靠性设计提供指导. 相似文献
994.
This article scrutinizes the features of viscous dissipation in the stagnation point flow past through a linearly stretched Riga wall by implementing Cattaneo-Christov heat flux model. Viscous dissipation is carried out in Cattaneo-Christov diffusion analysis for the first time in this letter. As a result of Cattaneo-Christov model, some extra terms of viscous dissipation are appeared in the energy equation. These extra terms of viscous dissipation are missing in the literature. On the utilization of suitable transformations, the equations governing the problem are reduced under the boundary layer approximation into the non-linear and dimensionless ordinary differential equations. Convergent approach is utilized to solve the dimensionless governing equations. The solution thus acquired is used to highlight the effects of emerging parameters on velocity distribution and fluid's temperature through the graphs. Features of the drag force (or skin friction co-efficient) are graphically interpreted. It is noticed that the presence of modified Hartman number helps to reduce the fluid's temperature but enhances the velocity profile. Further an enlargement in the value of thermal time relaxation parameter helps to decrease the temperature distribution. 相似文献
995.
The purpose of the present study is to examine the impact of initial geometric imperfection on the nonlinear dynamical characteristics of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) rectangular plates under a harmonic excitation transverse load. The considered plate is assumed to be made of matrix and single-walled carbon nanotubes (SWCNTs). The rule of mixture is employed to calculate the effective material properties of the plate. Within the framework of the parabolic shear deformation plate theory with taking the influence of transverse shear deformation and rotary inertia into account, Hamilton’s principle is utilized to derive the geometrically nonlinear mathematical formulation including the governing equations and corresponding boundary conditions of initially imperfect FG-CNTRC plates. Afterwards, with the aid of an efficient multistep numerical solution methodology, the frequency-amplitude and forcing-amplitude curves of initially imperfect FG-CNTRC rectangular plates with various edge conditions are provided, demonstrating the influence of initial imperfection, geometrical parameters, and edge conditions. It is displayed that an increase in the initial geometric imperfection intensifies the softening-type behavior of system, while no softening behavior can be found in the frequency-amplitude curve of a perfect plate. 相似文献
996.
E. MAGNUCKA-BLANDZI K. WISNIEWSKA-MLECZKO M. J. SMYCZYNSKI P. KEDZIA 《应用数学和力学(英文版)》2018,39(7):981-992
This paper is devoted to analytical and numerical studies of global buckling of a sandwich circular plate. The mechanical properties of the plate core vary along its thickness, remaining constant in the facings. The middle surface of the plate is its symmetrical plane. The mathematical model of the plate is presented. The field of displacements is formulated using the proposed nonlinear hypothesis that generalizes the classical hypotheses. The equations of equilibrium are formulated based on the principle of stationary total potential energy. The proposed mathematical model of the displacements considers the shear effect. The numerical model of the plate is also formulated with a view to verify the analytical one. Numerical calculations are carried out for the chosen family of plates. The values of the critical load obtained by the analytical and numerical methods are compared. The effects of the material properties of the core and the change of the plate radius on the critical load intensity are presented. 相似文献
997.
The time-dependent electro-viscoelastic performance of a circular dielectric elastomer (DE) membrane actuator containing an inclusion is investigated in the context of the nonlinear theory for viscoelastic dielectrics. The membrane, a key part of the actuator, is centrally attached to a rigid inclusion of the radius a, and then connected to a fixed rigid ring of the radius b. When subject to a pressure and a voltage, the membrane inflates into an out-of-plane shape and undergoes an inhomogeneous large deformation. The governing equations for the large deformation are derived by means of non-equilibrium thermodynamics, and viscoelasticity of the membrane is characterized by a rheological spring-dashpot model. In the simulation, effects of the pressure, the voltage, and design parameters on the electromechanical viscoelastic behaviors of the membrane are investigated. Evolutions of the considered variables and profiles of the deformed membrane are obtained numerically and illustrated graphically. The results show that electromechanical loadings and design parameters significantly influence the electro-viscoelastic behaviors of the membrane. The design parameters can be tailored to improve the performance of the membrane. The approach may provide guidelines in designing and optimizing such DE devices. 相似文献
998.
The common defects of the Roe scheme are the non-physical expansion shock and shock instability. By removing the momentum interpolation mechanism (MIM), an improved method with several advantages has been presented to suppress the shock instability. However, it cannot prevent the expansion shock and is incompatible with the traditional curing method for expansion shock. To solve the problem, the traditional curing mechanism is analyzed. Effectiveness of the traditional curing method is discussed, and several defects are identified, one of which leads to incompatibility between curing shock instability and expansion shock. Consequently, an improved Roe scheme is proposed, which is with low computational costs, concise, easy to implement, and robust. More importantly, the proposed scheme can simultaneously solve the problem of shock instability and expansion shock without additional costs. 相似文献
999.
考虑剪切效应,利用切比雪夫多项式构造严格满足表面切应力边界条件的轴向位移表达式,建立了短梁弯曲问题的新理论.利用奇异函数把作用在短梁上的复杂外载荷表示为分布载荷,推导出了短梁弯曲时的截面正应力公式及挠曲线表达式.把采用切比雪夫多项式推导出短梁的弯曲计算公式计算结果与弹性理论计算结果进行比较,可知该方法的计算精度较高.研究结果表明:在复杂外载荷作用下,当长高比小于等于6时,剪切变形对梁的弯曲挠度影响较大,而当长高比小于3时,剪切变形对梁的弯曲应力影响较大;因此建议采用切比雪夫多项式方法给出的挠度表达式、弯曲应力进行计算,因为切比雪夫多项式方法不但给出了复杂外载荷作用下梁截面挠度、弯曲应力的计算通式,而且该方法具有计算过程简便、精度高的优点. 相似文献
1000.
提出一种两步优化策略,以加筋板结构的固有频率最大化为目标函数,以结构所受外载荷作用的最大静变形为约束条件,开展薄板结构加筋构件的布局优化设计研究。为了降低加筋布局优化的难度,提高优化设计的效率,将加筋等效为一系列弹性铰(点)支撑,以便快速获得加筋横向移动的灵敏度信息。在基本不改变结构重量的情形下,通过合理布局加筋位置,能显著改善结构的刚度分布,提高结构的整体承载能力。随后,小幅调整加筋的截面尺寸,以满足对结构最大变形的设计要求。最后,用两个算例验证了所提优化方法的可行性和有效性。 相似文献