Optimization Design and Experiment of Ear-Picking and Threshing Devices of Corn Plot Kernel Harvester

In order to solve the problems of easy-to-break kernels and substantial harvest losses during kernel harvesting in breeding trials plot of corn, an ear-picking device and a threshing device of corn plot kernel harvester has been optimized. To automatically change the gap of the ear-picking plate, a self-elastic structure with compression spring and connecting rod is used. The ear-picking plate is glued, and an elastic rubber gasket is placed underneath it, which effectively improves the adaptability of the ear-picking device and reduces corn kernel collision damage during ear-picking. To ensure the self-purification of the ear-picking device, a combination of auger sieve hole cleaning device and lateral pneumatic auxiliary cleaning system is used. A dual-axial flow threshing device is designed, which uses a “U”-shaped conveying system to transport maize ears in the threshing chamber. The spacing of the concave sieve may be adjusted, and the residual kernels in the threshing chamber can be cleaned up after harvesting one plot by combining three cleanings, which meets the requirements of no mixing between plots. The force analysis of corn ears in the threshing chamber determines the best design plan for the forward speed, the speed of the second threshing drum, and the threshing gap. The breakage rate and non-threshing rate regression models were created using the quadratic regression orthogonal combination test, and the parameters were optimized using MATLAB. The verification test results showed that when the forward speed was 0.61 m/s, the second threshing drum speed was 500 r/min, and the threshing gap was 40 mm, the breakage rate was 1.47%, and the non-threshing rate was 0.89%, which met the kernel harvesting requirements in corn plots.

Dynamic Characteristics and Anti-slip Grasping of Two-Finger Translational Manipulator

Aiming at the problem of deformation and slip of disc-shaped rubber gasket in the process of grasping, a two-finger translational manipulator based on ABB1410 robot is designed. The kinematics model of the two-finger translational manipulator is established, and the geometric relationship between the motor angle and grasp position is obtained. Based on the two-dimensional force sensor, the dynamic characteristics of the two-finger translational manipulator were studied, and the relationship between the grasping force and the deformation and slip of the disc-shaped rubber gasket was obtained. A prototype of two-finger translational manipulator is developed. The experimental results show that when the grasping force is 5 N, small deformation and stable grasping can be achieved. The grasping and handling process of disk-shaped rubber gasket is designed based on Robot Studio software, and the verification experiments were carried out. The experimental results show that the system can achieve the small deformation and stable grasping of flexible objects, which is consistent with the simulation results. The research can provide theoretical and experimental basis for the design of automation system structure and process control.

Sensitivity Analysis of the Waterproof Performance of Elastic Rubber Gasket in Shield Tunnel

In order to study the waterproof performance of elastic rubber gasket in shield tunnel lining joints, an innovative sensitivity analysis method is proposed by combining the Monte Carlo method with the stochastic finite element method (FEM) in this paper. The sensitivity values of the waterproof performance respecting to elastic rubber gaskets are obtained via the ANSYS Probabilistic Design System (PDS) module, in which the parameters of material hardness, coordinates of the hole center, apertures are selected as random input variables. Meantime, the extent of the tolerance effect of the random parameters on the waterproof performance is explored.

Investigation of large-diameter flange joint with soft-gasket

This study focuses on behaviour of the flanged joint with a soft rubber gasket, which is a common type of gasket for evaporator structures. The assembled structure is tested according to EN 13445-3, and strain values are measured using strain gauges. The numerical analysis in ABAQUS comprises several models with different levels of detail. These models are calibrated according to test data. Recommendations regarding the model complexity that is required to obtain satisfactory prediction of non-linear behaviour of flange joints are presented and documented.

Forensic Engineering Investigation of the Catastrophic Breakdown of a Diesel Engine in an Emergency Generator Set

A large-displacement 16-cylinder diesel engine was coupled with a 1750 kW-rated generator set to provide emergency power to an international airport parking facility. It had been in service for seven years, and had accumulated only 242 operating hours from a regular monthly test procedure. On the day of the incident, less than three minutes after starting up, the engine began smoking, running roughly, and then failed catastrophically. A forensic engineering investigation was undertaken to determine the cause. Two cylinders in opposite banks had been damaged. The proverbial “smoking gun” was found — an obstruction comprising a rubber gasket within the main oil gallery leading to these cylinders. The investigation explored the probable method and means that this gasket was entrained into the gallery. The results of the analysis attempted to provide for an assessment of relative liability of the parties.