Abstract Laser beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. This paper defines mathematical models for surface roughness prediction (Ra, μm) and width of heat affected zone (HAZ, mm) during laser cutting of alloy steels 1.4571 and 1.4828 with nitrogen as assist gas. For defining appropriate mathematical models multiple regression analysis is used with four independent variables. Following parameters are varied: cutting speed, focus position, nitrogen assist gas pressure and stand-off. Obtained mathematical models describe dependence of Ra and HAZ from varied process parameters.

Abstract This paper deals with modeling and simulation of multibody systems consisting of rigid and flexible bodiesactuated by hydraulic motors. To develop the corresponding modelbond graph technique is used thatprovides a systematic component oriented methodology. The proposed procedure is explained on the example of arotary crane.The simulation model was developed and simulation conducted using BondSim© program. The model developed is based on physical modeling philosophy by systematically decomposing it into the components and using the models from theprogram library. Mathematical model of the system may be machine generated in the form of differential algebraic equations (DAEs) and solved using a solver capable of solving such models up to semi implicit index two models.