Hopfield Neural Network Method for Problem of Telescoping Path Optimization of Single-Cylinder Pin-Type Multisection Boom

Telescoping path optimization (TPO) of single-cylinder pin-type multisection boom (SPMB) is a practical engineering problem that is valuable to investigate. This article studies the TPO problem and finds the key of TPO is to obtain the maximum retraction backmost combination. A mathematic model on the basis of the quadratic penalty function of a Hopfield neural network (HNN) is constructed. Two strategies are presented to improve the performance of TPO model: one is proportional integral derivative (PID) strategy that adaptively adjusts the parameter λ of the constrained term and the parameter γ of the optimization objective term by controlling the value of constraint violation gk and the other is efficiency factor strategy that an efficiency factor is introduced in model for prioritizing the constrained term over the objective term. Data test shows that compared with the path of boom length changing before optimization, both the number of sections that need to be moved and the total travels of cylinder can be reduced by 10%-30% after optimization. Both the PID strategy and the efficiency factor strategy achieve good optimization effects. The efficiency factor strategy is excellent at moderating the conflicts between the constrained term and the objective term; thus the generations of the valid and the optimal solutions get well improved.

Idealized Methods for Nonlinear Welding Mechanics

Computational Welding Mechanics is established by Prof. Yukio Ueda and it has become an indispensable and powerful method for understanding complex mechanical phenomena in welding. To tackle practical engineering problem, large scale transient nonlinear problem must be solved. For this, various “Idealized Methods” for welding mechanics were proposed. Among them, Iterative Substructure Method for transient nonlinear welding problem and Inherent Deformation Method for prediction of welding distortion of large structures are presented together with their application to practical problems.

Fuzzy Reliability Theory Based on Membership Function

In this study, it is considered that the shape of membership function and the values of parameters are arbitrary, hence reliability parameters will be arbitrary, and some data are even absurd from the point of view of real life practice. An applied fuzzy reliability theory is applied to practical engineering problem. Method of fuzzy reliability evaluation are developed.

Meso-Scale Oriented Physical Simulation Model for Complex Product Maintenance in Virtual Environment

Large component disassembly is complex tasks, the collision during the operation process often cause component damage and deform, even bring safe accident and result in significant loss. This paper proposes to use Meso-dimential oriented physical simulation strategy to research the collision effect simulation and damage surface visualization of large component during disassembly operation. Meso-collide behavior of multi-particles is adapted to simulate the macro-collision of large component. The method has important significance for expanding the mechanical simulation theory and solving the complex practical engineering problem.

TOP JOINT STUDY ON TEMPERATURE STRESS FOR SUPER-LONG SLAB-COLUMN STRUCTURE

In this paper, top joint method is proposed to solve a practical engineering problem of temperature stress and temperature crack of super-long slab-column structure bearing temperature difference. From the study, it is shown that as for super-long slab-column structure undergoing temperature difference of inside and outside, joint located in bottom stories nearly has no influence on temperature stress and deformation while joint in top stories can significantly reduce temperature stress and deformation of super-long slab-column structures. In addition, comparison of joints located in top one story, top several stories and from bottom to top stories indicates that influences of them on temperature stress and deformation are similar. As for top joint method, among which cantilever plate method, double column method and corbel method are discussed and results indicate that influence effects of these methods on structures are similar.

Contact Stress Analysis of Gear of Crane Gearbox

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.