In this paper, the influence of the elastic foundation on the free vibration and buckling of thin-walled piezoelectric-based functionally graded materials (FGM) cylindrical shells under combined loadings is investigated. The equations of motion are obtained by using the چکیده کامل
In this paper, the influence of the elastic foundation on the free vibration and buckling of thin-walled piezoelectric-based functionally graded materials (FGM) cylindrical shells under combined loadings is investigated. The equations of motion are obtained by using the principle of Hamilton and Maxwell's equations and the Navier's type solution used to solve these equations. Material properties are changed according to power law in the direction of thickness. In this study, the effects of Pasternak elastic foundation coefficients and also the effects of material distribution, geometrical ratios and loading conditions on the natural frequencies are studied. It is observed that by increasing Pasternak elastic medium coefficients, the natural frequencies of functionally graded piezoelectric materials (FGPM) cylindrical shell always increases. The mode shapes of FGPM cylindrical shell has been shown in this research and the results show that the distribution of the radial displacements is more significant than circumferential and longitudinal displacements.
پرونده مقاله
In this research, Ride quality of a three-axle truck is investigated to understand its vibrationspecifications and influence of it on special load. The truck is Benz 2624, and the load is rathersensitive to vibrations. The system is considered for an off-road duty. Henc چکیده کامل
In this research, Ride quality of a three-axle truck is investigated to understand its vibrationspecifications and influence of it on special load. The truck is Benz 2624, and the load is rathersensitive to vibrations. The system is considered for an off-road duty. Hence, the vehicle is modeledas a nineteen-degree of freedom system and its equations of motion are derived by employingLagrange equation. Since, the physical parameters of the vehicle were not available; the truck ismodeled in Solidworks CAD software in order to obtain the material and dynamic properties ofeach component of the truck. Then, a code is developed in MATLAB to calculate naturalfrequencies and mode shapes of the truck and their corresponding vibrating components in criticalspeed. A simple model of the truck in ADAMS is employed for validation. The adoption of theresults verifies the equations. The developed model can also be used in newer truck with somemodifications. It is also necessary to have accurate data for input information in order to change thecurrent model for other utilities.
پرونده مقاله
Initially, the first aim of the present study is to model 3-axle rigid truck by developing a code in Matlab. Secondly, each equation should be drived by acquisition of Lagrange approach. After deriving equations successfully, validation is performed by some result which چکیده کامل
Initially, the first aim of the present study is to model 3-axle rigid truck by developing a code in Matlab. Secondly, each equation should be drived by acquisition of Lagrange approach. After deriving equations successfully, validation is performed by some result which was mentioned in Bohao Li's master thesis. Although the present approach is totally different from the approach that Boahao Li used in his analysis but the deviation of the present results from that thesis on average is 7 percent which shows an acceptable accuracy in our current numerical approach. In the present study 19 degree of freedoms is used for determining natural frequency and dominant motions. By having dominant motion, it is possible to clarify which region is in endangering of resonance. This paper presents a portion of the results that have been gathered and for watching new result in this field, it is recommended to read our future papers. Solidworks CAD software is also used to calculate mass properties of several components that used in our present study.
پرونده مقاله
سازه‌های پوسته‌ای جدار نازک دارای وزن سبک و مقاومت بالا می‌باشند ظرفیت باربری، رفتار کمانشی و فراکمانشی مخازن فولادی جدار نازک، به وجود ناکاملی‌های هندسی بسیار حساس می‌باشد. با توجه به کم بودن ضخامت جداره سازه‌های پوسته‌ای امکان ایجاد هرگونه تغییر شکل و اختلال بر روی سط چکیده کامل
سازه‌های پوسته‌ای جدار نازک دارای وزن سبک و مقاومت بالا می‌باشند ظرفیت باربری، رفتار کمانشی و فراکمانشی مخازن فولادی جدار نازک، به وجود ناکاملی‌های هندسی بسیار حساس می‌باشد. با توجه به کم بودن ضخامت جداره سازه‌های پوسته‌ای امکان ایجاد هرگونه تغییر شکل و اختلال بر روی سطوح دیواره وجود دارد. با توجه به انواع خطا در حین ساخت یا مونتاژ، مخازن طراحی شده بصورت ایده‌آل ساخته نمی‌شوند و دارای مقداری خطای هندسی هستند. این ناکاملی‌ها ممکن است در فرآیند نورد، جابجایی پانل‌ها، نصب یا جوشکار بوجود آیند. گزارش‌های زیادی در باره ناکاملی حاصل از اثر عمل جوشکاری و تاثیر کاهند‌گی آن بر ظرفیت باربری محوری در دست است. تحقیقات جامع و کاملی بر روی اثر ناکاملی هندسی اولیه بر روی اشکال مدی مخازن فولادی، و اثر آن بر ظرفیت باربری مخازن فولادی صورت نگرفته که مورد توجه تحقیق حاضر است. در این تحقیق، به بررسی رفتار واقعی پوسته‌های استوانه‌ای دارای ناکاملی هندسی اولیه بر روی اشکال مدی مخازن فولادی در مرحله پیش از کمانش و پس از کمانش، و بررسی اثر ناکاملی هندسی اولیه بر روی اسلاشینگ در مخازن فولادی پرداخته شده است، با استفاده از نرم افزار اجزاء محدود، ABAQUS و صحت سنجی نتایج حاصل از تحلیل و آنالیز غیرخطی با نتایج آزمایشگاهی پرداخته شده است. ناکاملی هندسی شکل مدها را تغییر داده است. اثر ناکاملی هندسی اولیه روی مقدار اسلاشینگ ناچیز بوده است.
پرونده مقاله
سکوی نشر دانش
سند یا سکوی نشر دانش ،سامانه ای جهت مدیریت حوزه علمی و پژوهشی نشریات دانشگاه آزاد می باشد
