通过对某橡胶材料标准试件的单轴拉伸、平面拉伸和等双轴拉伸的应力-应变数据的测试,并利用最小二乘原理识别了5种常见橡胶超弹性本构模型的参数,对比了不同模型间的拟合精度。以某款车型的橡胶隔振器为实例,计算不同本构模型在3种典型...通过对某橡胶材料标准试件的单轴拉伸、平面拉伸和等双轴拉伸的应力-应变数据的测试,并利用最小二乘原理识别了5种常见橡胶超弹性本构模型的参数,对比了不同模型间的拟合精度。以某款车型的橡胶隔振器为实例,计算不同本构模型在3种典型工程应变下的力-位移曲线,并与实测数据进行对比。结果表明,Mooney-Rivlin模型在处理较小应变数据时具有较好的计算精度和计算稳定性,Van der Waals模型和3阶Ogden模型在处理较大应变数据时具有较好的计算精度。展开更多
A novel performance model of losses of pump was presented,which allows an explicit insight into the losses of various friction pairs of pump.The aim is to clarify that to what extent the hydro-mechanical losses affect...A novel performance model of losses of pump was presented,which allows an explicit insight into the losses of various friction pairs of pump.The aim is to clarify that to what extent the hydro-mechanical losses affect efficiency,and to further gain an insight into the variation and distribution characteristics of hydro-mechanical losses over wide operating ranges.A good agreement is found in the comparisons between simulation and experimental results.At rated speed,the hydro-mechanical losses take a proportion ranging from 87% to 89% and from 68% to 97%,respectively,of the total power losses of pump working under 5 MPa pressure conditions,and 13% of full displacement conditions.Furthermore,within the variation of speed ranging from 48% to 100% of rated speed,and pressure ranging from 14% to 100% of rated pressure,the main sources of hydro-mechanical losses change to slipper swash plate pair and valve plate cylinder pair at low displacement conditions,from the piston cylinder pair and slipper swash plate pair at full displacement conditions.Besides,the hydro-mechanical losses in ball guide retainer pair are found to be almost independent of pressure.The derived conclusions clarify the main orientations of efforts to improve the efficiency performance of pump,and the proposed model can service for the design of pump with higher efficiency performance.展开更多
Based on the theory of geomechanics and using geologic analytical methods,analyed the fault characteristics, mechanical properties, displacement mode, tectonic system, structural pattern, activity mode of stress, tect...Based on the theory of geomechanics and using geologic analytical methods,analyed the fault characteristics, mechanical properties, displacement mode, tectonic system, structural pattern, activity mode of stress, tectonic activity, and tectonic evolution ofthe area of the Xiamen submarine tunnel, the strike NWW 295^(。), which is the main unfavorable geological structure that affects the safety of the tunnel construction; the macrogeological prediction concludes that weathered troughs and groundwater-rich zonesformed by its larger-scale fault fracture zones are the main unfavorable geological bodiesprovides a basis for preventing the geo-logical hazards in the tunnel construction.展开更多
文摘通过对某橡胶材料标准试件的单轴拉伸、平面拉伸和等双轴拉伸的应力-应变数据的测试,并利用最小二乘原理识别了5种常见橡胶超弹性本构模型的参数,对比了不同模型间的拟合精度。以某款车型的橡胶隔振器为实例,计算不同本构模型在3种典型工程应变下的力-位移曲线,并与实测数据进行对比。结果表明,Mooney-Rivlin模型在处理较小应变数据时具有较好的计算精度和计算稳定性,Van der Waals模型和3阶Ogden模型在处理较大应变数据时具有较好的计算精度。
基金Project(2014CB046403)supported by the National Basic Research Program of ChinaProject(2013BAF07B01)supported by the National Key Technology R&D Program of China
文摘A novel performance model of losses of pump was presented,which allows an explicit insight into the losses of various friction pairs of pump.The aim is to clarify that to what extent the hydro-mechanical losses affect efficiency,and to further gain an insight into the variation and distribution characteristics of hydro-mechanical losses over wide operating ranges.A good agreement is found in the comparisons between simulation and experimental results.At rated speed,the hydro-mechanical losses take a proportion ranging from 87% to 89% and from 68% to 97%,respectively,of the total power losses of pump working under 5 MPa pressure conditions,and 13% of full displacement conditions.Furthermore,within the variation of speed ranging from 48% to 100% of rated speed,and pressure ranging from 14% to 100% of rated pressure,the main sources of hydro-mechanical losses change to slipper swash plate pair and valve plate cylinder pair at low displacement conditions,from the piston cylinder pair and slipper swash plate pair at full displacement conditions.Besides,the hydro-mechanical losses in ball guide retainer pair are found to be almost independent of pressure.The derived conclusions clarify the main orientations of efforts to improve the efficiency performance of pump,and the proposed model can service for the design of pump with higher efficiency performance.
基金Supported by the National Natural Science Foundation of China(10702072)the Education Department of Hebei Province (Z2006428)Doctoral Foundation of Hebei Normal University of Science & Technology
文摘Based on the theory of geomechanics and using geologic analytical methods,analyed the fault characteristics, mechanical properties, displacement mode, tectonic system, structural pattern, activity mode of stress, tectonic activity, and tectonic evolution ofthe area of the Xiamen submarine tunnel, the strike NWW 295^(。), which is the main unfavorable geological structure that affects the safety of the tunnel construction; the macrogeological prediction concludes that weathered troughs and groundwater-rich zonesformed by its larger-scale fault fracture zones are the main unfavorable geological bodiesprovides a basis for preventing the geo-logical hazards in the tunnel construction.
