تئوري عمومي-محلي اصلاح شده براي تحليل استاتيكي ورق هاي ساندويچي و كامپوزيتي تحت بار عرضي

Modified Global-local theory for investigating composite and sandwich plates under static transverse loading

در مقاله كنوني، يك تئوري محلي-عمومي اصلاح شده به منظور تحليل ورق هاي چندلايه و ساندويچي ارائه شده است. از ويژگيهاي بارز آن، درنظرگرفتن جابجايي هسته در راستاي ضخامت و محاسبه تنش هاي برشي عرضي با استفاده از حل معادلات تعادل سه بعدي الاستيسيته ميباشد. نتايج حاصله هم براي ورق هاي ساندويچي نازك و هم ورق هاي ضخيم ازدقت مناسبي برخوردارند. همچنين بدليل درنظر گرفتن تغيير شكل پذيري هسته، در هر دو حالتي كه هسته ورق ساندويچي نرم ويا سفت باشد تئوري جواب هاي قابل قبولي ارائه داده است. در نهايت بعد از صحت سنجي، تاثير پارامترهاي مختلف بر عملكرد ورق به دقت بررسي شده است.

In the present article, a global-local theory with three-dimensional elasticity corrections is employed to trace the local and instantaneous variations of various displacement and stress components of sandwich and composite plates. The governing equations are extracted based on Hamilton principle. One of the key features of the proposed theory is incorporation of the transverse flexibility of the core; a fact that is crucial when studying behaviors of thick or soft core sandwich plates. Since the transverse shear stresses are extracted based on the 3D elasticity theory, the interlaminar continuity condition of the transverse shear stresses is met. The verification results show that the presented finite element formulation is efficient and leads to accurate results, even for thick or soft core sandwich plates. A comprehensive parametric study is accomplished to evaluate effects of different parameters such as stiffness of the core material and boundary conditions. Finally, the obtained results verified by the available results existed in the literature.