Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these pr...Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.展开更多
A revised displacement discontinuity method(DDM) program is developed for the simulation of rock joint propagation and dilatancy analysis. The non-linear joint model used in the program adopts Barton-Bandis normal def...A revised displacement discontinuity method(DDM) program is developed for the simulation of rock joint propagation and dilatancy analysis. The non-linear joint model used in the program adopts Barton-Bandis normal deformation model, Kulhaway shear deformation model and Mohr-Coulomb criterion. The joint propagation criterion is based on the equivalent stress intensity factor which can be obtained by regression analysis. The simulated rock joint propagation accords well with the existing knowledge. The closure and opening of joint is investigated by DDM, and it is shown that if the opening volume of propagated joint is larger than closure volume of the old joint, the joint dilatancy occurs. The dilatancy condition is mainly controlled by the normal stiffness of the rock joint. When the normal stiffness is larger than the critical value, joint dilatancy occurs. The critical normal stiffness of rock joint changes with the joint-load angle, and joint dilatancy is most possible to occur at 30°.展开更多
Design increasingly plays a pivotal role in achieving justice for all.However,there are often gaps between visions and implementation due to the variety of factors and stakeholders involved in design practice.Through ...Design increasingly plays a pivotal role in achieving justice for all.However,there are often gaps between visions and implementation due to the variety of factors and stakeholders involved in design practice.Through literature review and a keyword co-occurrence analysis,this paper investigates current landscape justice research and identifies the distinguishing concerns in design,and highlights the importance of systematic thinking in achieving landscape justice.By examining the practices of the British company Building Design Partnership(BDP),a multinational design company,this paper identifies BDP’s three key design principles as experiences can be followed for landscape justice:design for inclusion,design for resilience,and design for future ecosystems.The paper also addresses potential challenges and conflicts in implementing landscape justice across different contexts and highlights multinational design companies’efforts to mediate between various stakeholders.Finally,this paper demonstrates that design companies can contribute to 1)bridging social and environmental justice through landscape design,2)achieving the visions promoted by scholars,3)identifying and deploying diverse approaches to achieving landscape justice with their sensitivity to practical problems,and 4)fostering integrated feedback loops via both top-down and bottom-up approaches to ensure effective implementation of landscape justice.展开更多
文摘Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.
基金Project(2009318000046) supported by the Western Transport Technical Program of the Ministry of Transport,China
文摘A revised displacement discontinuity method(DDM) program is developed for the simulation of rock joint propagation and dilatancy analysis. The non-linear joint model used in the program adopts Barton-Bandis normal deformation model, Kulhaway shear deformation model and Mohr-Coulomb criterion. The joint propagation criterion is based on the equivalent stress intensity factor which can be obtained by regression analysis. The simulated rock joint propagation accords well with the existing knowledge. The closure and opening of joint is investigated by DDM, and it is shown that if the opening volume of propagated joint is larger than closure volume of the old joint, the joint dilatancy occurs. The dilatancy condition is mainly controlled by the normal stiffness of the rock joint. When the normal stiffness is larger than the critical value, joint dilatancy occurs. The critical normal stiffness of rock joint changes with the joint-load angle, and joint dilatancy is most possible to occur at 30°.
文摘Design increasingly plays a pivotal role in achieving justice for all.However,there are often gaps between visions and implementation due to the variety of factors and stakeholders involved in design practice.Through literature review and a keyword co-occurrence analysis,this paper investigates current landscape justice research and identifies the distinguishing concerns in design,and highlights the importance of systematic thinking in achieving landscape justice.By examining the practices of the British company Building Design Partnership(BDP),a multinational design company,this paper identifies BDP’s three key design principles as experiences can be followed for landscape justice:design for inclusion,design for resilience,and design for future ecosystems.The paper also addresses potential challenges and conflicts in implementing landscape justice across different contexts and highlights multinational design companies’efforts to mediate between various stakeholders.Finally,this paper demonstrates that design companies can contribute to 1)bridging social and environmental justice through landscape design,2)achieving the visions promoted by scholars,3)identifying and deploying diverse approaches to achieving landscape justice with their sensitivity to practical problems,and 4)fostering integrated feedback loops via both top-down and bottom-up approaches to ensure effective implementation of landscape justice.
