This paper is devoted to the modal analysis and buckling of a stiffened plate with simple supported conditions within the framework of shell theory. The main objective of the finite element analysis is to investigate the natural frequencies of this stiffened structure subjected to uniaxial compression on two opposite edges of the plate. In this study, the numerical analysis is performed for such a design of the stiffed plate which has already been optimized for uniaxial compression, some design variables and the cost of welding, and the objective function to be minimized is defined as the material cost. The various Young’s modulus of the base plate and the stiffeners are given thus assuming that the plate parts (the base plate and ribs) were made of different steel materials.

In the structural optimization of a ring-stiffened cylindrical shell the unknown variables are the shell thickness as well as the thickness and the number of flat rings. The shell diameter enables to realize a belt-conveyor structure inside of the shell. The uniformly distributed vertical load consists of dead and live load. The design constraints relate to the local shell buckling strength, to the panel ring buckling and to the deflection of the simply supported bridge. The cost function includes the material and fabrication costs. The fabrication cost function is formulated according to the fabrication sequence and includes also the cost of forming of shell elements into the cylindrical shape as well as the cost of cutting of the flat plate ring-stiffeners. Since the shell thickness does not depend on number of ring-stiffeners (n), the nopt is calculated for a selected region of n.

No abstract

This paper briefly outlines the design of replaceable cutting teeth of bucket chain excavator, which are attached to a holder with a detachable joint. The description of the rock cutting process is very complex, so the investigation of the effect of lateral forces is complicated through cutting tests. We use accordingly numerical analysis to examine some segments of the cutting process. Our main objective is to present the finite element analysis of cutting teeth in which the linear increase of the lateral force is taken into consideration. The finite element analysis is a powerful technique, which is enabled to compute the stress and displacement distribution in cutting teeth. The simulation results have shown that the maximum stresses decrease if the lateral force increases. The geometry of the optimized cutting teeth will be safe under the given loading conditions.

No abstract