An evolutionary approach for cooling system optimization in plastic injection moulding

The cooling process is of great importance in plastic injection moulding as it has a direct impact on both productivity and product quality. Cooling process optimization is a sophisticated task which includes not only the design of cooling channels but also the selection of process parameters. Most existing optimization systems focus on either cooling channel design or process parameter selection but not both. This paper explores an approach to optimize both cooling channel design and process condition selection simultaneously through an evolutionary algorithm. The prototype system proposed in this paper is an integration of the genetic algorithm and CAE (Computer-Aided Engineering) technology. The aim is to launch a computerized system that can guide the optimization of the cooling process in plastic injection moulding. The objective is to achieve the most uniform cavity surface temperature to assure product quality.     

Plate perforation by deformable projectiles — A plastic wave theory

A one-dimensional wave propagation model of plate perforation is developed for cylindrical projectiles impacting plates at normal obliquity. This theory assumes that the projectile and plate materials are rigid-linearly strain-hardening and rigid-perfectly plastic respectively, with respect to engineering stress and strain. During penetration, the projectile deforms and a plug forms in the plate. The plug which is sheared from the plate is larger than the initial cross-section of the projectile. Residual velocity, plug mass and final plug thickness are determined for this model and compared with experiments on ductile metal plates impacted at velocities larger than the minimum perforation velocity.     

An enhanced pipe elbow element—application in plastic limit analysis of pipe structures

In this paper, we present a new pipe elbow element based on a previous simplified model proposed by Bathe and Almeida [1, 2] and modified by Militello and Huespe [3]. It is really a beam‐type element but it describes the ovalization, warping, radial expansion and non‐symmetric deformation of cross‐section of curved pipe with Fourier series. Therefore, it could model precisely enough a real pipe elbow structure but remains simple. The extensive loading cases are effectively implemented by the proposed numerical techniques and displacement model. The developed element is used in this paper in plastic limit analysis of pipe elbow structures. This is realized by means of a direct mathematical programming technique. Various elastic and plastic limit state analyses of straight pipes and elbow structures are presented, which illustrates the efficiency of the element and the numerical method. Copyright © 1999 John Wiley & Sons, Ltd.