The problems on the non-uniqueness and stability of a two-family fiber- reinforced anisotropic incompressible hyper-elastic square sheet under equibiaxial tensile dead loading are examined within the framework of fini...The problems on the non-uniqueness and stability of a two-family fiber- reinforced anisotropic incompressible hyper-elastic square sheet under equibiaxial tensile dead loading are examined within the framework of finite elasticity. For a two-family fiber-reinforced square sheet, which is in-plane symmetric and subjected to the in-plane symmetric tension in dead loading on the edges, three symmetrically deformed configu- rations and six asymmetrically deformed configurations are possible for any values of the loading. Moreover, another four bifurcated asymmetrically deformed configurations are possible for the loading beyond a certain criticM value. The stability of all the solutions is discussed in comparison with the energy of the sheet. It is shown that only one of the symmetric solutions is stable when the loading is less than the critical value. However, this symmetric solution will become unstable when the loading is larger than the critical value, while one of the four bifurcated asymmetric solutions will be stable.展开更多
A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution ...A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution of meshing gears is developed. The versatility of the procedure for both numerical accuracy and computational efficiency is verified by numerical analysis of meshing gear teeth.展开更多
There is an urgent need to develop optimal solutions for deformation control of deep high‐stress roadways,one of the critical problems in underground engineering.The previously proposed four‐dimensional support(here...There is an urgent need to develop optimal solutions for deformation control of deep high‐stress roadways,one of the critical problems in underground engineering.The previously proposed four‐dimensional support(hereinafter 4D support),as a new support technology,can set the roadway surrounding rock under three‐dimensional pressure in the new balanced structure,and prevent instability of surrounding rock in underground engineering.However,the influence of roadway depth and creep deformation on the surrounding rock supported by 4D support is still unknown.This study investigated the influence of roadway depth and creep deformation time on the instability of surrounding rock by analyzing the energy development.The elastic strain energy was analyzed using the program redeveloped in FLAC3D.The numerical simulation results indicate that the combined support mode of 4D roof supports and conventional side supports is highly applicable to the stability control of surrounding rock with a roadway depth exceeding 520 m.With the increase of roadway depth,4D support can effectively restrain the area and depth of plastic deformation in the surrounding rock.Further,4D support limits the accumulation range and rate of elastic strain energy as the creep deformation time increases.4D support can effectively reduce the plastic deformation of roadway surrounding rock and maintain the stability for a long deformation period of 6 months.As confirmed by in situ monitoring results,4D support is more effective for the long‐term stability control of surrounding rock than conventional support.展开更多
According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is un...According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is under consideration. A new approach to improve the quality of spiral bevel gear is illustrated emphatically.展开更多
基金supported by the National Natural Science Foundation of China(No.10772104)the Shanghai Leading Academic Discipline Project(No.S30106)
文摘The problems on the non-uniqueness and stability of a two-family fiber- reinforced anisotropic incompressible hyper-elastic square sheet under equibiaxial tensile dead loading are examined within the framework of finite elasticity. For a two-family fiber-reinforced square sheet, which is in-plane symmetric and subjected to the in-plane symmetric tension in dead loading on the edges, three symmetrically deformed configu- rations and six asymmetrically deformed configurations are possible for any values of the loading. Moreover, another four bifurcated asymmetrically deformed configurations are possible for the loading beyond a certain criticM value. The stability of all the solutions is discussed in comparison with the energy of the sheet. It is shown that only one of the symmetric solutions is stable when the loading is less than the critical value. However, this symmetric solution will become unstable when the loading is larger than the critical value, while one of the four bifurcated asymmetric solutions will be stable.
文摘A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution of meshing gears is developed. The versatility of the procedure for both numerical accuracy and computational efficiency is verified by numerical analysis of meshing gear teeth.
基金support from the National Key Research and Development Program of China(Nos.2023YFC2907300 and 2019YFE0118500)the National Natural Science Foundation of China(Nos.U22A20598 and 52104107)the Natural Science Foundation of Jiangsu Province(No.BK20200634).
文摘There is an urgent need to develop optimal solutions for deformation control of deep high‐stress roadways,one of the critical problems in underground engineering.The previously proposed four‐dimensional support(hereinafter 4D support),as a new support technology,can set the roadway surrounding rock under three‐dimensional pressure in the new balanced structure,and prevent instability of surrounding rock in underground engineering.However,the influence of roadway depth and creep deformation on the surrounding rock supported by 4D support is still unknown.This study investigated the influence of roadway depth and creep deformation time on the instability of surrounding rock by analyzing the energy development.The elastic strain energy was analyzed using the program redeveloped in FLAC3D.The numerical simulation results indicate that the combined support mode of 4D roof supports and conventional side supports is highly applicable to the stability control of surrounding rock with a roadway depth exceeding 520 m.With the increase of roadway depth,4D support can effectively restrain the area and depth of plastic deformation in the surrounding rock.Further,4D support limits the accumulation range and rate of elastic strain energy as the creep deformation time increases.4D support can effectively reduce the plastic deformation of roadway surrounding rock and maintain the stability for a long deformation period of 6 months.As confirmed by in situ monitoring results,4D support is more effective for the long‐term stability control of surrounding rock than conventional support.
文摘According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is under consideration. A new approach to improve the quality of spiral bevel gear is illustrated emphatically.
