Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied ...Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.展开更多
The stress and the strain should be defined as statistical variables averaged over the representative volume elements for any real continuum system.It is shown that their nonlinear spatial distributions undermine the ...The stress and the strain should be defined as statistical variables averaged over the representative volume elements for any real continuum system.It is shown that their nonlinear spatial distributions undermine the classical framework of solid mechanics and may cause non-ignorable errors to the solutions.With considering the high-order gradients of the stress and the strain,a two-step solution scheme is proposed to compensate for the influence.Through a revisit to three simple but typical problems,i.e.,the hole size-dependence of the fracture strength of perforated plates,the indentation depth-dependence of the measured elastic modulus by micro-indentation tests,and the tensile necking of metallic materials as well as hyperelastic materials,the effect of the nonlinear spatial distribution of stress and strain on solving these problems is illustrated.The observed size effect and the instability of deformation can be quantitatively explained if the effect is properly considered by the proposed method.展开更多
基金Supported by National Key Technology Research and Development Program of China(No.2012BAF01B07)
文摘Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.
基金supported by the Original Exploration Project of Natural Science Foundation of China(No.12150001)the National Key Research and Development Program of China(No.2018YFB1900400)+1 种基金the National Natural Science Foundation of China(No.11832019)the Nuclear Power Technology Innovation Center of Science Technology and Industry for National Defense of China(No.HDLCXZX-2021-HD-035)。
文摘The stress and the strain should be defined as statistical variables averaged over the representative volume elements for any real continuum system.It is shown that their nonlinear spatial distributions undermine the classical framework of solid mechanics and may cause non-ignorable errors to the solutions.With considering the high-order gradients of the stress and the strain,a two-step solution scheme is proposed to compensate for the influence.Through a revisit to three simple but typical problems,i.e.,the hole size-dependence of the fracture strength of perforated plates,the indentation depth-dependence of the measured elastic modulus by micro-indentation tests,and the tensile necking of metallic materials as well as hyperelastic materials,the effect of the nonlinear spatial distribution of stress and strain on solving these problems is illustrated.The observed size effect and the instability of deformation can be quantitatively explained if the effect is properly considered by the proposed method.
