Nonlinear dynamic deformation simulation for helical rod like objects

In this paper, dynamic deformation simulation of an elastic helical rod with circular cross-section under axial tension is discussed on the basis of the Kirchhoff dynamic analogy. Firstly, equilibrium equations of an elastic rod described by Euler angles are established in the Frenet coordinates of the centerline. To get solutions of the equations, through a cylindrical coordinate system founded by end constraint, mathematical analytical formulations were used to describe elastic rod configuration are gained on the basis of Saint-Venant Principle of Elasticity, in the form of Elliptic functions. Then, based on the conclusions of static analysis, the relationship between geometric parameters and end constraint of helical rods is qualitatively analyzed. Finally, nonlinear dynamic deformation simulation with constraint force change is realized in a virtual environment to verify the effectiveness of the above algorithm

An efficient 3D point cloud data denoising algorithm for ship block visual measurement

For the 3D point cloud data aquired by laser scanning measurement of ship block, an efficient denoising algorithm based on image and normal vector threshold judgement is proposed. Firstly, large scale noise points are eliminated using global threshold judgement based image, then Kuwahara filter algorithm is used for data smoothing and a denoising algorithm based on normal vector threshold judgement is proposed to eliminate noises point excluding ship manufacture sections. The experiment result demonstrates that not only the proposed denoising algorithm keeps key data points but also avoids bluring point cloud boundary and eliminates noise points effectively

Energy Analysis and Verification of a Constant-Pressure Elastic-Strain Energy Accumulator Based on Exergy Method

Focusing on the low energy-storage efficiency and unstable energy output of existing accumulators, this paper proposes a novel constant-pressure elastic-strain energy accumulator based on the rubber material hyperelastic effect. The proposed accumulator can store and release energy at a constant pressure. Based on the exergy analysis method, the charging/discharging energy storage efficiency of a constant-pressure elastic-strain energy accumulator was analyzed. Then, the Mullins effect on the rubber airbag over multiple charging/discharging cycles was studied. Finally, a test platform was established to verify the energy storage efficiency, as well as the expansion and contraction pressure stability of the rubber accumulator during charging/discharging cycles. The experimental results showed that the energy storage efficiency calculation by the exergy analysis method was more accurate compared with the enthalpy analysis method. In tests with more than 200 cycles, the rubber airbag energy storage efficiency was always higher than 76%, and the expansion and contraction pressure errors at a steady state were less than 2.92 and 1.79 kPa, respectively. The results showed that the rubber airbag could be used as an effective energy storage component, which is very meaningful for energy recovery in pneumatic or hydraulic systems

Energy Analysis and Verification of a Constant-Pressure Elastic-Strain Energy Accumulator Based on Exergy Method

Focusing on the low energy-storage efficiency and unstable energy output of existing accumulators, this paper proposes a novel constant-pressure elastic-strain energy accumulator based on the rubber material hyperelastic effect. The proposed accumulator can store and release energy at a constant pressure. Based on the exergy analysis method, the charging/discharging energy storage efficiency of a constant-pressure elastic-strain energy accumulator was analyzed. Then, the Mullins effect on the rubber airbag over multiple charging/discharging cycles was studied. Finally, a test platform was established to verify the energy storage efficiency, as well as the expansion and contraction pressure stability of the rubber accumulator during charging/discharging cycles. The experimental results showed that the energy storage efficiency calculation by the exergy analysis method was more accurate compared with the enthalpy analysis method. In tests with more than 200 cycles, the rubber airbag energy storage efficiency was always higher than 76%, and the expansion and contraction pressure errors at a steady state were less than 2.92 and 1.79 kPa, respectively. The results showed that the rubber airbag could be used as an effective energy storage component, which is very meaningful for energy recovery in pneumatic or hydraulic systems

The simulation of cable harness based on mass-spring model

The simulation of cable harnesses is challenging due to the complex structure and the large deformation during the assembly operations. In this paper an improved mass-spring model is approached to simulate the shape of cable harnesses and to calculate the deformation of cable harnesses. Based on a virtual software platform Open Cascade and using Newmark-β algorithm which could reduce the instabilities of equation, the simulation is completed. Then, a cable geometry measurement bench with the 3D laser scan technology is construed to verify the accuracy of the algorithm. The result shows the model could simulate the deformation very well

Energy-Saving for Industrial Pneumatic Actuation Systems by Exhausted Air Reuse Based on a Constant Pressure Elastic Accumulator

Exhausted air reuse is one of the most important energy-saving methods for pneumatic actuation systems. However, traditional exhausted air storage tanks have the disadvantages of unstable pressure and low energy density. To solve these problems, this paper presents an energy-saving method by exhausted air reuse for industrial pneumatic actuation systems based on a constant pressure elastic accumulator. Employing the hyperelastic mechanical properties of rubber, a constant pressure energy storage accumulator is designed and applied to a pneumatic circuit for exhausted air recovery and energy saving. In the circuit, the accumulator recovers exhausted air from a primary cylinder and supplies it to another secondary cylinder. Then the secondary cylinder no longer needs air supply from the air compressor to achieve the purpose of energy saving. The energy-saving mathematical model of the circuit is established using air consumption, and the system operation test bed is built to verify the energy-saving efficiency. Results show that the maximum energy-saving efficiency of the system is 54.1% under given working conditions, and the stability of the cylinder can be improved

The simulation of cable harness based on mass-spring model

The simulation of cable harnesses is challenging due to the complex structure and the large deformation during the assembly operations. In this paper an improved mass-spring model is approached to simulate the shape of cable harnesses and to calculate the deformation of cable harnesses. Based on a virtual software platform Open Cascade and using Newmark-β algorithm which could reduce the instabilities of equation, the simulation is completed. Then, a cable geometry measurement bench with the 3D laser scan technology is construed to verify the accuracy of the algorithm. The result shows the model could simulate the deformation very well

The simulation of cable harness based on mass-spring model

The simulation of cable harnesses is challenging due to the complex structure and the large deformation during the assembly operations. In this paper an improved mass-spring model is approached to simulate the shape of cable harnesses and to calculate the deformation of cable harnesses. Based on a virtual software platform Open Cascade and using Newmark-β algorithm which could reduce the instabilities of equation, the simulation is completed. Then, a cable geometry measurement bench with the 3D laser scan technology is construed to verify the accuracy of the algorithm. The result shows the model could simulate the deformation very well