Applied Mechanics and Materials Vols. 444-445

Abstract: The structural characteristics of a wharf segment may be modeled by using the simplified model due to unacceptable matrix sizes. The concept of simplified model is introduced at first. The locations of simplified model that represent original structure are determined by the locations of pile groups in defined areas. Force-displacement curve is calculated for wharf structure by pushover analysis, and simplified model is constituted applying estimated secant stiffness and effective damping according to force-displacement curve. Peak value of seismic response is estimated using elastic modal response spectra analysis and compared with simulated results from nonlinear time history analysis. It is proved that peak value of seismic response can be calculated using simplified model rapidly, and close to time history analysis result.

Abstract: It cant be ignored when steel members generating forces and stresses in torsion. To get the exact results, you need to solve several higher order differential equations, and it is much difficult for actual engineering designs. Based on Elastic theory of thin-walled structures, this thesis tries to introduce an approximate, convenient and high-precision way to solve problems about torsion.

Abstract: Based on non-probabilistic reliability theory, a new non-probabilistic model of reliability is proposed in this paper. The new model which extends the traditional interval model is available for the non-uniform distribution of random variable and could be more widely used in practical application. A utility method to analyze the crack propagation life under given reliability is put forward based on the proposed model, and its theoretical basis is also proved by theory deducing. This simple and practicable method avoids complex integral operation and the errors caused by the hypothetic distribution form. Finally, the validity and efficiency of this method is verified by numerical examples.

Abstract: Three dimensional (3D) cubic models with spherical pores ranged as Face-Centered Cubic (FCC) lattices are constructed to simulate the microstructures of rubber foams with various relative densities. The Mooney-Rivlin strain energy potential model is adopted to characterize the hyperelasticity of the constituent solid from which the foams are made. Large compressive deformations of closed-celled rubber foams are calculated by the iterative algorithm. Numerical results show that with the decreasing of foam relative densities, the effects of air pressures in cells on foam compressive stresses increase. When the ratio of initial Yangs modulus of cell material to the initial air pressure in cells reaches 2 order of magnitude, the influence of air pressures in cells can neglect.

Abstract: This work describes our efforts towards building an object-oriented software framework for Interface Stress Element Method (ISEM), a newly developed numerical method for discontinuous and fracture problems. Based on the improved Interface Stress Element Method and object-oriented technology, we recognized major objects in ISEM and their interrelations. Then the class hierarchy, modules organization and data interfaces scheme were presented. We also addressed implementation issues and main features of this framework, which integrated a solver, a post-processor, a preprocessor and a model data converter. Numerical examples demonstrated that this system works well, which is a good starting point for further development.

Abstract: According to the definition of the Buffeting, it is caused by a fluctuating wind. Since fluctuating wind is wind speed changing with time in the atmosphere, it will cause the vibration of the structure. And pulsating wind reflects the atmospheric boundary layer wind disturbance and randomness. In the paper, Stable Type Suspension Bridge (STSB) is researched for buffeting problem. A finite element model of the bridge is set up using the finite element software. The buffeting response of the bridge is calculated and studied. The influence of the opposite tensional structures in the bridge on buffeting response of the bridge is assessed.

Abstract: A simulation method of macro-and meso-scales is developed for particle reinforce composite materials. The two-scale modeling based on homogenization theory enables to formulate the macro scale problem with Finite Element Method (FEM), while the meso-scale one with Voronoi Cell Finite Element Method (VCFEM). Dangerous regions are identified in macro scale computing period, which lately be meshed into Voronoi Cells in meso-scale period to get a more accurate solution. Representative numerical examples are presented to demonstrate the capability of the proposed two-scale analysis method of particulate reinforce composite materials.

Abstract: The 3-D multi-body contact dynamics simulation model was built by ADAMS base on the Hertz contact theory and multi-body contact dynamics, which considered the dynamics relationship among the ball, ring and cage of the bearing. Considering the clearancesfrictions and loads, results that contained deformation and displacement of the bearing, trajectory of the CM of the cage and the dynamic contact force were obtained by means of the 3-D multi-body contact dynamics model simulation and statics calculation. The outcomes got from two different methods are consistent, so the 3-D multi-body contact dynamics simulation model has the positive significance on dynamic design and engineering application of the bearing.

Abstract: This paper presents a new numerical method for obtaining the complex stress intensity factor with an interface crack in bi-materials using photoelastic isochromatic fringe numbers N. The theoretical solution of stress field at the crack tip was deduced from Muskhelishvilis stress function and an undetermined term σ₀ which is a function of material properties was added to this theoretical solution. A partial differential iterative equation with fast convergence was formed by applying the photoelastic theory. The complex stress intensity factor K=K₁+iK₂ and σ₀ were obtained by Newton-Raphson iteration method and K domain was discussed. The simulant photoelastic isochromatic fringe pattern could be generated through image processing and numerical calculation according to K and σ₀. The simulant isochromatic fringe pattern accords with experimental photoelastic isochromatic fringe pattern, so it is practicable for this numerical method of obtaining the complex stress intensity factor.