Abstract. This contribution deals with replacing of metals part by plastics products. There are several benefits of this application -minimize part cost, corrosion resistance, integrating more components into one part etc. Material selection depending on the design of plastic part. It is necessary has to withstand the same load as metal part. To fulfill this requirement solve fiber reinforced plastics. Also it is convenient to substitute wall sections with ribbed structure. Mechanical properties this part could be important affected by fiber orientation. Results of fiber orientation can be used in stress analysis for better prediction to mechanical load. This analysis is performed in this study on bolted flange joint.