Kuo Liu

Rapid design of a screw drive in-pipe robot based on parameterized simulation technology:

The screw drive in-pipe robot is a type of effective intelligent equipment for inspecting pipeline failure. In-pipe robots have a wide range of design parameters due to varied pipe types and application conditions. Experiential or theoretical design means cannot ensure the validity and success rate, which leads to the increase in production cost and cycle. Therefore, in order to solve the rapid design problem of screw drive in-pipe robots, a parameterized simulation system based on ADAMS secondary development technology and a simple design strategy is proposed. Firstly, the motion principles of screw drive in-pipe robots are analyzed to establish a generalized design model. Then, the key parameters of the geometric structure are extracted and associated, which work as the input variables to design the robotic model. Then the general parameterized simulation system is established based on the CMD language of ADAMS simulation software. Finally, a simple design strategy is proposed and a design application case for pipeline diameter of 225 mm is studied. The results show that the parameterized simulation system can build and test varied screw drive in-pipe robot models quickly by only inputting some design parameters. The proposed design system and strategy can help realize the production of a screw drive in-pipe robot rapidly.

Plane residual stress measurement using ultrasonic considering weak anisotropy of metallic material

Ultrasonic velocity variation (UVV) along different directions induced by material weak anisotropy will lead to residual stress measurement error using ultrasonic inevitably. In this research, the influence of weak anisotropy on residual stress measurement is analyzed theoretically and experimentally. Firstly, the in-plane acoustoelastic wave equation is modified by considering material anisotropy, which can be characterized by two in-plane anisotropic parameters. Further, an analysis model is also established to express the linear superposition of weak anisotropy and acoustoelastic effect on UVV. Based on this, a plane residual stress measurement method has been developed, which was verified using the rolling aluminum alloy plate after friction stir welding. From the comparison with hole-drilling method, it was adequate and capable to measure the plane residual stress by the relative UVV along three particular directions.Ultrasonic velocity variation (UVV) along different directions induced by material weak anisotropy will lead to residual stress measurement error using ultrasonic inevitably. In this research, the influence of weak anisotropy on residual stress measurement is analyzed theoretically and experimentally. Firstly, the in-plane acoustoelastic wave equation is modified by considering material anisotropy, which can be characterized by two in-plane anisotropic parameters. Further, an analysis model is also established to express the linear superposition of weak anisotropy and acoustoelastic effect on UVV. Based on this, a plane residual stress measurement method has been developed, which was verified using the rolling aluminum alloy plate after friction stir welding. From the comparison with hole-drilling method, it was adequate and capable to measure the plane residual stress by the relative UVV along three particular directions.