Experiment and dynamic simulation were combined to obtain the loads on bicycle frame. A dynamic model of body-bicycle system was built in ADAMS. Then the body gestures under different riding conditions were captured b...Experiment and dynamic simulation were combined to obtain the loads on bicycle frame. A dynamic model of body-bicycle system was built in ADAMS. Then the body gestures under different riding conditions were captured by a motion analysis system. Dynamic simulation was carried out after the data of body motions were input into the simulation system in ADAMS and a series of loads that the body applied on head tube, seat pillar and bottom bracket were obtained. The results show that the loads on flame and their distribution are apparently different under various riding conditions. Finally, finite element analysis was done in ANSYS, which showed that the stress and its distribution on frame were apparently different when the flame was loaded according to the bicycle testing standard and simulation respectively. An efficient way to obtain load on bicycle flame accurately was proposed, which is sig- nificant for the safety of cycling and will also be the basis for the bicycle design of digitalization, lightening and cus- tomization.展开更多
This paper intends to develop finite element models that can simulate vehicle load moving on pavement system and reflect the pavement response of vehicle and pavement interaction.We conduct parametric analysis conside...This paper intends to develop finite element models that can simulate vehicle load moving on pavement system and reflect the pavement response of vehicle and pavement interaction.We conduct parametric analysis considering the influences of asphalt concrete layer modulus and thickness,base layer modulus and thickness,and subgrade modulus on pavement surface displacement,frequency,and strain response.The analysis findings are fruitful.Both the displacement basin width and maximum value of dynamic surface displacements are larger than those of static surface displacements.The frequency is positively correlated with the pavement structure moduli,and negatively correlated with the pavement structure thicknesses.The shape of dynamic and static tensile strain is similar along the depth of the pavement structure.The maximum value of dynamic tensile strain is larger than that of static tensile strain.The frequency of entire pavement structure holds more significant influence than the surface displacement and strain do.The subgrade modulus has a significant effect on surface displacement,frequency and strain.展开更多
In this study,ground vibrations due to dynamic loadings from trains moving in subway tunnels were investigated using a 2.5D finite element model of an underground tunnel and surrounding soil interactions.In our model,...In this study,ground vibrations due to dynamic loadings from trains moving in subway tunnels were investigated using a 2.5D finite element model of an underground tunnel and surrounding soil interactions.In our model,wave propagation in the infinitely extended ground is dealt with using a simple,yet efficient gradually damped artificial boundary.Based on the assumption of invariant geometry and material distribution in the tunnel's direction,the Fourier transform of the spatial dimension in this direction is applied to represent the waves in terms of the wave-number.Finite element discretization is employed in the cross-section perpendicular to the tunnel direction and the governing equations are solved for every discrete wave-number.The 3D ground responses are calculated from the wave-number expansion by employing the inverse Fourier transform.The accuracy of the proposed analysis method is verified by a semi-analytical solution of a rectangular load moving inside a soil stratum.A case study of subway train induced ground vibration is presented and the dependency of wave attenuation at the ground surface on the vibration frequency of the moving load is discussed.展开更多
基金Supported by Special Fund Project for Technology Innovation of Tianjin (No. 10FDZDGX00500)Tianjin Product Quality Inspection Technology Research Institute (No. 11-03)
文摘Experiment and dynamic simulation were combined to obtain the loads on bicycle frame. A dynamic model of body-bicycle system was built in ADAMS. Then the body gestures under different riding conditions were captured by a motion analysis system. Dynamic simulation was carried out after the data of body motions were input into the simulation system in ADAMS and a series of loads that the body applied on head tube, seat pillar and bottom bracket were obtained. The results show that the loads on flame and their distribution are apparently different under various riding conditions. Finally, finite element analysis was done in ANSYS, which showed that the stress and its distribution on frame were apparently different when the flame was loaded according to the bicycle testing standard and simulation respectively. An efficient way to obtain load on bicycle flame accurately was proposed, which is sig- nificant for the safety of cycling and will also be the basis for the bicycle design of digitalization, lightening and cus- tomization.
基金supported by the National Natural Science Foundation of China(No.51178456)。
文摘This paper intends to develop finite element models that can simulate vehicle load moving on pavement system and reflect the pavement response of vehicle and pavement interaction.We conduct parametric analysis considering the influences of asphalt concrete layer modulus and thickness,base layer modulus and thickness,and subgrade modulus on pavement surface displacement,frequency,and strain response.The analysis findings are fruitful.Both the displacement basin width and maximum value of dynamic surface displacements are larger than those of static surface displacements.The frequency is positively correlated with the pavement structure moduli,and negatively correlated with the pavement structure thicknesses.The shape of dynamic and static tensile strain is similar along the depth of the pavement structure.The maximum value of dynamic tensile strain is larger than that of static tensile strain.The frequency of entire pavement structure holds more significant influence than the surface displacement and strain do.The subgrade modulus has a significant effect on surface displacement,frequency and strain.
基金Project supported by the National Natural Science Foundation of China (Nos. 51178418 and 51222803)the National Key Technology R&D (863) Program of China (No. 2009BAG12A01-B12-3)
文摘In this study,ground vibrations due to dynamic loadings from trains moving in subway tunnels were investigated using a 2.5D finite element model of an underground tunnel and surrounding soil interactions.In our model,wave propagation in the infinitely extended ground is dealt with using a simple,yet efficient gradually damped artificial boundary.Based on the assumption of invariant geometry and material distribution in the tunnel's direction,the Fourier transform of the spatial dimension in this direction is applied to represent the waves in terms of the wave-number.Finite element discretization is employed in the cross-section perpendicular to the tunnel direction and the governing equations are solved for every discrete wave-number.The 3D ground responses are calculated from the wave-number expansion by employing the inverse Fourier transform.The accuracy of the proposed analysis method is verified by a semi-analytical solution of a rectangular load moving inside a soil stratum.A case study of subway train induced ground vibration is presented and the dependency of wave attenuation at the ground surface on the vibration frequency of the moving load is discussed.
