Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping chara...Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids(D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.展开更多
In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course ...In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.展开更多
The quality of bonding is often a concern in rubber-to-metal bonded parts with regard to the integrity and stability of the structure. In this study, shearography has been used to detect the out-of-plane deformation o...The quality of bonding is often a concern in rubber-to-metal bonded parts with regard to the integrity and stability of the structure. In this study, shearography has been used to detect the out-of-plane deformation of the defects caused by thermal and vacuum stresses. A sample of the vulcanized styrene-butadiene rubber bonded to steel with known artificial voids was prepared and during bonding process a region was glued with thick adhesives. The rubber surface of the sample was inspected in thermal radiation and vacuum modes respectively with a self-designed shearography device. Meanwhile, a numerical simulation was conducted to predict the out-of-plane deformation of the rubber surface in these two stress modes. Results from the numerical simulation and the experiments indicated that the debonding defects could be inspected in both loading modes. In the thermal radiation mode the region with thick adhesives could be identified successfully. This study provides a guideline for quality control of rubber-to-metal structures using an optical method.展开更多
文摘Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids(D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.
基金Supported by Shandong Province Outstanding Young Scientist Award Fund(No.BS2014SF016)the National Natural Science Foundation of China(No.50979067)+1 种基金Ludong University Doctor Introduction Foundation(No.LY2014026 and No.LY2014028)the Open Research Fund Program of State Key Laboratory of Water Resources and Hydropower Engineering Science(No.2012B104)
文摘In this paper, silt sediment is considered to be Bingham body, which is made up of coarse and fine particles in front of a hydraulic gate. The coarse and fine particles provide friction and shear stress in the course of opening the gate. They constitute together the adhesion force of the sediment. Based on this viewpoint, this paper puts forward a formula for the effect of silt sediment on the lifting force. The formula includes gate weight, down-suction force, sealing rubber friction, plus-weight, water-column pressure, plus-silted-sediment weight and rolling(or sliding)-bearing friction. Finally, the verification results show that the formula has certain reliability and the calculation accuracy can meet the need of practical engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.11172161,11372173 and 11472163)National Basic Research Program of China(Grant No.2014CB046203)+1 种基金the Innovation Program of Shanghai Municipal Education Commission(Grant No.12ZZ092)the Shanghai Municipal Science and Technology Commission(Grant No.1304H197500)
文摘The quality of bonding is often a concern in rubber-to-metal bonded parts with regard to the integrity and stability of the structure. In this study, shearography has been used to detect the out-of-plane deformation of the defects caused by thermal and vacuum stresses. A sample of the vulcanized styrene-butadiene rubber bonded to steel with known artificial voids was prepared and during bonding process a region was glued with thick adhesives. The rubber surface of the sample was inspected in thermal radiation and vacuum modes respectively with a self-designed shearography device. Meanwhile, a numerical simulation was conducted to predict the out-of-plane deformation of the rubber surface in these two stress modes. Results from the numerical simulation and the experiments indicated that the debonding defects could be inspected in both loading modes. In the thermal radiation mode the region with thick adhesives could be identified successfully. This study provides a guideline for quality control of rubber-to-metal structures using an optical method.
