Applied Mechanics and Materials Vols. 668-669

Abstract: In this paper, the finite analytic method is developed to solve the two-dimensional fluid flows in heterogeneous porous media with full tensor permeability. With the help of power-law behaviors of pressure and its gradient around the node, a local analytic nodal solution is derived for the pressure equation. Then it is applied to construct a finite analytic numerical scheme which deals with the divergence in pressure gradient. The numerical examples show that the convergence speed of the numerical scheme is fast and independent of the permeability heterogeneity. In contrast, the convergence speed slow rapidly as the heterogeneity increases when the traditional scheme is used.

Abstract: The mechanic behavior and debonding process of pipe joints’ interface are the key points of pipe system. Load carrying capacity of pipe joints is the most important indicator that industry concerns. In this paper, results of finite element method (FEM) using ABAQUS modelling are given. Through parametric study, the load-displacement relationship, ultimate load and ductility of the joints can be explained. The thickness of adhesive layer is also taken into consideration.

Abstract: The force of the concrete pumping work of mine rotor wet spraying machine is analysis in this paper, focusing on the piston assembly and cylinder bore rotor stress analysis during nesting, selecting the important structural parameters and optimizing the structure, to ensure the normal and efficient function of wet spraying working to improve the stability of wet spray machine work and life, and providing an important reference for the structural design of the piston assembly.

Abstract: In this paper, the super-elastic shape memory alloy (SMA) composite cables are used for vibration control of high-rise chemical towers during the free vibration. The displacement and velocity response to initial displacements were studied by the lumped mass method combined with Newmark integration method. It is found that super-elastic SMA cables can reduce the free vibration amplitudes and shorten the attenuation period of high-rise chemical towers effectively.

Abstract: The landing gear occupies an important position in the design, manufacture and use of the aircraft. But it spends a lot of time and resources in a real experiment. The rapid development of computer simulation technology makes it possible to have a virtual analysis of the landing gear. Based on typical CAD software UG, finite element simulation software ANSYS and virtual prototyping software ADAMS, a mixed rigid-flexible nose landing gear model is constructed in this paper. The joint application will play their advantages respectively.

Abstract: Timoshenko beam is an extension of Euler-Bernoulli beam to interpret the transverse shear impact. The more refined Timoshenko beam relaxes the normality assumption of plane section that remains plane and normal to the deformed centerline. The manuscript presents some exact concise analytic solutions on deflection and stress resultants of NET single-span Timoshenko beam with general distributed force and 6 kinds of standard boundary conditions, adopting its counterpart Euler-Bernoulli beam solutions. Engineering example shows that scale impact would not unveil itself for micro structure with micrometer μm-order length, yet will be prominent for nanostructure with nanometer nm-order length. When simply supported CNTs is undergone to a concentrative force at the median and complete bend moment, scale action is observed along the ensemble CNTs, while it unfurls itself the most at the position of the concentrated strength. When a clamped-free CNTs is exposed to a centralized force at the mesial and distributed force, there is no scale impact about the deflection at all positions on the left border of the concentrated strength position, while such operation inspires at once at all positions on the right margin of the concentrated strength position. When a clamped-clamped CNTs is lain under a concentrative strength at the middle, the deflection of NET Euler-Bernoulli CNTs reflects scale effect completely. Notable differences between the deflection of Euler-Bernoulli CNTs and that of Timoshenko CNTs are reflected at large ratio of diameter versus length. The deflection of NET clamped-free and simply supported Timoshenko beam doesn’t introduce surplus scale process in terms of its counterpart, NET Euler-Bernoulli beam. However, the deflection of NET clamped-clamped Timoshenko beam does involve additional scale impact solely including the method when the concentrated strength position is at the midway in the beam-length direction.

Abstract: With consideration of asperity contact, the minimum oil film thickness and friction power loss are calculated by simultaneous solution of the dynamics, blow-by and lubrication of piston ring pack. Take the piston ring pack in the first cylinder from the free end of a six-cylinder diesel engine for example, results show that the asperity contact takes place at all of the compression rings and oil ring; the minimum oil film thickness is 1.04μm at the top ring; the total friction loss power is 0.94kW, the top ring accounts for 37.2%, the second ring accounts for 33.0%, the oil ring accounts for 29.8%.

Abstract: In this article, the entity model of the bearing-rotor system is established and meshed in ANSYS. The natural frequency and vibration mode of the rotor system is analyzed in order to avoid the occurrence of resonance. At the same time, the results showed that not only the location of the unbalance incentive of the system should be taken into account, but also consider the size of the unbalanced force.

Abstract: The rupture and its several influence factors on the short crossbeam of sieve case during square plansifter running are investigated. Aimed at the system consisting of a square plansifter and some suspenders, the FEM is employed to establish structure dynamic model for obtaining dynamic response. According to the contrast of the vibration data of sieve body in experiment and the displacement response from FEA, the finite element model is modified. Results show that the position where the maximum stress happens in FEA and the position of actual rupture are the same. Furthermore, the influence of various factors on the maximum stress of three dangerous positions are computed and analyzed. The results presented in this paper possess an important reference value to structural improvement and dynamic optimization of square plansifter.

Abstract: A non-linear torsional vibration model of harmonic gear drive is proposed in the current study. The model includes clearance, nonlinearity torsional stiffness and nonlinearity damping. The clearance model is developed by introducing the piecewise-linear displacement functions. The function of nonlinearity torsional stiffness is obtained by torsional stiffness experimental. The model of nonlinearity damping is used to describe the process of transmission. The non-linear differential equations are solved using Runge-Kutta method. The numerical simulation results show that the influence of nonlinear factors on dynamic behavior, which has chaotic characteristics, is remarkable.