بررسي ارتعاش محوري ميله با تكيه گاه ويسكوالاستيك

اخيرا استفاده از مواد ويسكوالاستيك در بخش هاي مختلف مهندسي به دليل خصوصيات فيزيكي و مكانيكي آنها افزايش پيدا كرده است. رفتار اين مواد در استهلاك انرژي و ميرايي نيروهاي زياد و حدي باعث ايجاد علاقه در مهندسين جهت مطالعه و بررسي كاربرد اين مواد گرديده است. در اين مطالعه ارتعاش محوري ميله اي با مصالح الاستيك و همچنين ويسكوالاستيك با وجود تكيه گاه مرزي و مياني ساخته شده از مواد ويسكوالاستيك مورد بررسي قرار گرفته است. خصوصيات مكانيكي مواد ويسكوالاستيك توسط مدل كلوين – ويت تعميم يافته توصيف شده است. معادلات حاكم با روش اجزاي محدود در حوزه زمان حل شدند و نتايج عددي به صورت تاريخچه جابه جايي در چندين مقطع و تاريخچه تنش در ميله و تكيه گاه ها، تهيه و مقايسه اي جامع بين حالت هاي مذكور صورت گرفت و نشان داده شد كه استفاده از تكيه گاه ويسكوالاستيك در ميرايي و كاهش جابه جايي و ارتعاش ميله بسيار موثر و كارآمد مي باشد و مي تواند موجب كاهش تنش و تغييرات آن با گذشت زمان در ميله و تكيه گاه ها گردد. The use of viscoelastic materials have recently been increased in several areas of engineering due to their advantageous physical and mechanical properties. Regarding the latter, the energy dissipation behavior and dampening of extreme forces are of great interest for structural engineers. In this study, axial vibration of an elastic and a viscoelastic rod with the end and middle supports made from viscoelastic materials was investigated. The viscoelastic property was described using the generalized Kelvin-Voigt mechanical model. The governing equations were solved using the finite element method in the time domain. The numerical results were provided in terms of the displacement-time history in several sections and the stress-time history in the rod and its supports and a detailed comparison was made between aforementioned cases. The responses subject to step load excitation revealed that the use of viscoelastic materials as support is very effective and efficient at damping and decreasing the displacement and vibration of the rod. They can also reduce the stress and its rate of changes significantly because of their energy dissipation nature.

The use of viscoelastic materials have recently been increased in several areas of engineering due to their advantageous physical and mechanical properties. Regarding the latter, the energy dissipation behavior and dampening of extreme forces are of great interest for structural engineers. In this study, axial vibration of an elastic and a viscoelastic rod with the end and middle supports made from viscoelastic materials was investigated. The viscoelastic property was described using the generalized Kelvin-Voigt mechanical model. The governing equations were solved using the finite element method in the time domain. The numerical results were provided in terms of the displacement-time history in several sections and the stress-time history in the rod and its supports and a detailed comparison was made between aforementioned cases. The responses subject to step load excitation revealed that the use of viscoelastic materials as support is very effective and efficient at damping and decreasing the displacement and vibration of the rod. They can also reduce the stress and its rate of changes significantly because of their energy dissipation nature