Program „The modeling of design of multi-layer construction elements subjected by turning“ is created for students of mechanical engineering course and designers. Using this program it is possible to calculate inertia momentum of pole area, stiffness for shear, shear stresses, and maximum meanings of shear stress and twisting angle. The input parameters are shear modulus of materials, inner diameter of pivot, thickness and material of each layer, torsion moment and length of pivot. The output is initial data and results of calculation. In addition the diagram of distribution of stresses is drawn.

Šiuo metu medžiagų poreikis gamybai yra labai išaugęs.Todėl inžinieriai stengiasi atrasti vis naujų arba tobulesnių medžiagų. Daugiasluoksnės konstrukcijos įgauna vis didesnę paklausą, dėl savo savikainos ir pritaikymo galimybės.Naudojant šias medžiagas galima gauti norimas masės ir stiprumo konstrukcijas. Daugiasluoksniams konstrukciniams elementams gaminti naudojamos tokios medžiagos kaip:stiklo, boro, plastiko pluoštai ir t.t. Mes išanalizavome 6 metrų sijas iš dviejų medžiagų. Mes analizavome skirtingus skerspjūvius ir skirtingus sluoksnių storius, paskaičiavome skerspjūvių stiprumą ir standumą. Taip pat analizavome racionalių sijų pranašumus. Nustatyta kurie skerspjūviai yra pranašiausi. Taip pat nustatyta, kad racionalios sijos yra pranašesnės už vientiso skerspjūvio. Gavome, kad racionalios sijos yra pigesnės iki 30 procentų. / Dolieba M. Influence of analysis of Strength and Stiffness of Two- Ply Beam: Master thesis of mechanical engineer / research advisor Assoc. Prof. habil. Dr. J. Bareišis; Šiauliai University, Technological Faculty, Mechanical Engineering Department.- Šiauliai, 2007. Materials for construction needful more and more. Engineers trying to get more perfection materials. Multiplayer construction is very popular at this time, because it is cheaper, we can reduce the weight and the forse. Different products and constructions elements using multiplayer constructions from glass, carbon, boric plastic and other materials. We analysing six meters beam from two ply. We take different cross-section and different high of ply and analysing strength and stiffness. After we calculating how less material need for rational beam. In result we see which cross-section are best for using. At first we see that multiplayer constructions have the advantage before common beams. We get that rational beam are thirty percent cheaper.

Composite materials are formed by combiing two or more materials that have quite different properties. The different materials work together to give the composite unique properties, but within the composite you can easily tell the the different materials apart – they do not dissolve or blend into each other. Modern aviation, both military and civil, is a prime example. It would be much less efficient without composites. In fact, the demands made by that industry for materials that are both light and strong has been the main force driving the development of composites. The greatest advantage of composite materials is strength and stiffness combined with lightness. By choosing an appropriate combination of reinforcement and matrix material, manufacturers can produce properties that exactly fit the requirements for a particular structure for a particular purpose. In general, composite materials are very durable. The downside of composites is usually the cost. Although manufacturing processes are often more efficient when composites are used, the raw materials like steel, but in many cases they are just what we need.