In recent years, the developments in clean, renewable and efficient energy policies have been enabled to design new and innovative heat exchangers. The plate heat exchangers have crucial importance among these innovative products due to compact size and thermally efficient behaviour. There are many studies dealing with the thermo-fluidic behaviour of brazed plate heat exchangers. However, since the usage of these products often includes relatively high pressure and toxic fluids, the examination of structural stability of these products is cruical from the point of scientific perspective view. There are very few studies of plate heat exchangers regarding to mechanical aspects. Accordingly, in this thesis it is intended to investigate structural behaviour of brazed plate heat exchangers by numerical methods. For this purpose, the material properties of brazing interface of plate heat exchangers have been determined by experimental methods. The tensile and stress based fatigue experiments are carried out and the material models have been obtained. The validation of material model which is used in numerical analysis has been carried out by explicit method using maximum displacement as a boundary condition. The mechanical behaviour of chevron type brazed plate heat exchangers has been investigated by considering effect of chevron angle under different pressure conditions. The results have been obtained numerically in two stages; static structural analysis results and fatigue analysis. The numerical results show that the chevron angle has a significant effect on the formation of brazing points of plate heat exchangers. The dimensions of brazing points directly affects the overall structural behaviour of plate heat exchanger. It is observed that the single brazing point surface area and homogeneous distribution of brazing points on the plates are more critical than the total surface area. Finally, it is thought that the developed numerical methodology will lead to the structural design of brazed plate heat exchangers before the production of protoype molding and experimental testing. Eventually, it will be advantageous in terms of mold costs and time spent for experimental testing.