Setting up a pair of moving frames on the two pitch circles, the instantaneous contact point being considered the attendant point of the frames, the equation of the trace of the contact points in the frame being p = p...Setting up a pair of moving frames on the two pitch circles, the instantaneous contact point being considered the attendant point of the frames, the equation of the trace of the contact points in the frame being p = p(t~), we can deduce that the basic rule for the gear profiles is dp / ds = - csos 0 where s is the are length of the pitch circles. Giving a known function of p = p (0), we can obtain the equations of the two conjugate gear profiles and the curvatures and inductive curvature of the profiles. The second order contact phenomenon that a given gear profile can contact with the mating gear at two points simultaneously is discussed by the method of moving frames.展开更多
In this paper,an innovative type of thin-walled structures,the convex-concave honeycomb columns(CCHCs)with transverse negative Poisson’s ratio(NPR),is proposed for energy absorbers by replacing the cell walls of squa...In this paper,an innovative type of thin-walled structures,the convex-concave honeycomb columns(CCHCs)with transverse negative Poisson’s ratio(NPR),is proposed for energy absorbers by replacing the cell walls of square honeycomb lattice columns with sine-shaped or zigzag-shaped walls of equal mass.Numerical simulations show that,under axial impact,contrary to the conventional square honeycomb columns of equal mass,the transverse cross section of NPR CCHC shrinks inward,making the cell walls of CCHC contact and interact sufficiently with each other and thus dissipate the impact energy much more effectively.By suitably adjusting the transverse NPR,the CCHC can have the combined advantages of effective total energy absorption,high specific energy absorption and low maximum peak crushing force.The research of this paper provides a new strategy for the design of high-performance energy absorbers widely used in the engineering fields of vehicle engineering,aerospace engineering etc.展开更多
文摘Setting up a pair of moving frames on the two pitch circles, the instantaneous contact point being considered the attendant point of the frames, the equation of the trace of the contact points in the frame being p = p(t~), we can deduce that the basic rule for the gear profiles is dp / ds = - csos 0 where s is the are length of the pitch circles. Giving a known function of p = p (0), we can obtain the equations of the two conjugate gear profiles and the curvatures and inductive curvature of the profiles. The second order contact phenomenon that a given gear profile can contact with the mating gear at two points simultaneously is discussed by the method of moving frames.
基金supported by the National Natural Science Foundation of China(Grant Nos.12021002,12072222,12132010 and 11991032)the State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures(Grant No.SKLTESKF1901).
文摘In this paper,an innovative type of thin-walled structures,the convex-concave honeycomb columns(CCHCs)with transverse negative Poisson’s ratio(NPR),is proposed for energy absorbers by replacing the cell walls of square honeycomb lattice columns with sine-shaped or zigzag-shaped walls of equal mass.Numerical simulations show that,under axial impact,contrary to the conventional square honeycomb columns of equal mass,the transverse cross section of NPR CCHC shrinks inward,making the cell walls of CCHC contact and interact sufficiently with each other and thus dissipate the impact energy much more effectively.By suitably adjusting the transverse NPR,the CCHC can have the combined advantages of effective total energy absorption,high specific energy absorption and low maximum peak crushing force.The research of this paper provides a new strategy for the design of high-performance energy absorbers widely used in the engineering fields of vehicle engineering,aerospace engineering etc.
