Papers by Author: Jing Yuan

Abstract: In order to solve problems and modify design deficiencies in safety testing of baby carriages, a new collision and impact test machine is designed. Force and movement are analyzed by physical modeling of the test machine. The use of virtual prototyping technology to simplify the testing machine model and velocity, acceleration parameters and energy loss diagrams of measured object are obtained by dynamic simulation of the test machine model. The analysis results are obtained by comparative simulation of group data which show error of the test machine on collision velocity and impact energy fully meet the requirements of domestic and international testing standards and much lower than error of traditional experimental methods. The experimental method is verified feasibility and advanced in theory and provides a theoretical basis for developing the test machine.

Abstract: Operation of two-dimensional Power Spectral Density (2-D PSD) of large optics wavefront is briefly described and PSD collapse is introduced to evaluate the intermediate frequency error property of wavefront. As PSD collapse is Radon transform projection of 2-D Power Spectral Density at any angle, all valid data of wavefront of optics are used in calculation of the PSD collapse and the features of 1-D PSD were inherited in PSD collapse. Although PSD collapse is as same as 1-D PSD in unit and behavior style, it is better for evaluating intermediate frequency error property of optics wavefront than 1-D PSD or 2-D PSD. As PSD collapse calculation uses all valid data of evaluated optics wave front and can be directly perceived through its profile, the PSD collapse may possibly be the standard evaluating method of PSD.