The evolution of leakage is studied using detailed contact finite element analysis. The distribution of stress at the gasket is analyzed using a contact condition based on slide-line elements using ABAQUS, a commercia...The evolution of leakage is studied using detailed contact finite element analysis. The distribution of stress at the gasket is analyzed using a contact condition based on slide-line elements using ABAQUS, a commercial finite element code, Slide-line elements also take into account pressure penetration as contact that is lost between flange and gasket. Results are presented for a particular flange, a raised face flange sealed by a mild steel gasket. A comparison of the results from the gasket contact analysis and the contact conditions specified by the ASME Boiler and Pressure Vessel Code, Sections VIII, Division 1 shows that the conditions specified in the ASME Code predict leakage relatively accurately.展开更多
The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rub...The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt （SMA）, ultra-thin surfacing （UTS） and porous asphalt （PA）. The asphalt surface morphologies of these mixes were captured by using an X-ray tornographer, from which the resulting images micromechanical finite element （FE） meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic （V-E） materials and the formulation was given in the large deformation frame- work. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a simaificant effect on rubber friction.展开更多
This paper uses a mathematical method to develop an analytical solution to the local buckling behaviour of long rectangular plates resting on tensionless elastic Winkler foundations and under combined uniform longitud...This paper uses a mathematical method to develop an analytical solution to the local buckling behaviour of long rectangular plates resting on tensionless elastic Winkler foundations and under combined uniform longitudinal uniaxial compressive and uniform in-plane shear loads. Fitted formulas are derived for plates with clamped edges and simplified supported edges. Two examples are given to demonstrate the application of the current method： one is a plate on tensionless spring foundations and the other is the contact between the steel sheet and elastic solid foundation. Finite element （FE） analysis is also conducted to validate the analytical results. Good agreement is obtained between the current method and FE analysis.展开更多
文摘The evolution of leakage is studied using detailed contact finite element analysis. The distribution of stress at the gasket is analyzed using a contact condition based on slide-line elements using ABAQUS, a commercial finite element code, Slide-line elements also take into account pressure penetration as contact that is lost between flange and gasket. Results are presented for a particular flange, a raised face flange sealed by a mild steel gasket. A comparison of the results from the gasket contact analysis and the contact conditions specified by the ASME Boiler and Pressure Vessel Code, Sections VIII, Division 1 shows that the conditions specified in the ASME Code predict leakage relatively accurately.
基金by the National Priorities Research Program (NPRP) award (NPRP No. 7-482-2-184: Thermo-mechanical Tire-Pavement Interaction: Computational Modeling and Field Measurements) from the Qatar National Research Fund (a member of the Qatar Foundation)
文摘The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt （SMA）, ultra-thin surfacing （UTS） and porous asphalt （PA）. The asphalt surface morphologies of these mixes were captured by using an X-ray tornographer, from which the resulting images micromechanical finite element （FE） meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic （V-E） materials and the formulation was given in the large deformation frame- work. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a simaificant effect on rubber friction.
文摘This paper uses a mathematical method to develop an analytical solution to the local buckling behaviour of long rectangular plates resting on tensionless elastic Winkler foundations and under combined uniform longitudinal uniaxial compressive and uniform in-plane shear loads. Fitted formulas are derived for plates with clamped edges and simplified supported edges. Two examples are given to demonstrate the application of the current method： one is a plate on tensionless spring foundations and the other is the contact between the steel sheet and elastic solid foundation. Finite element （FE） analysis is also conducted to validate the analytical results. Good agreement is obtained between the current method and FE analysis.
