بررسی پارامترهای موثر در تحلیل ترموالاستیک درام دوار هدفمند در موتور توربینی هوایی تحت بار حرارتی غیرخطی

در این پژوهش، یک حل تحلیلی دقیق برای تحلیل ترموالاستیک یک درام دوار در هر دو حالت همگن و ساخته‌شده از مواد مدرج تابعی (fgm) تحت بارگذاری‌های داخلی و خارجی ارائه شده است. در حالت fgm تغییرات خواص مکانیکی در راستای شعاعی درام به‌صورت نمایی فرض شده است. حرارت وارده به‌صورت تابع دلخواهی از شعاع بر سازه اثر می‌کند. برای اعمال گرادیان حرارتی موجود در درام مورد بحث از تابع انتقال حرارت در شرایط پایدار استفاده‌ شده است. پس از محاسبه جابجایی و مولفه‌های تنش اعمالی، اثر عوامل مختلف موثر بر نتایج نظیر سرعت دورانی، مقدار و نوع بارگذاری وارده بر روی سطوح داخلی و خارجی، ضخامت درام و ثابت‌های غیر همگن بررسی‌شده است. همچنین تنش‌های معادل با استفاده از معیار وون میزز به‌دست‌آمده است. نتایج نشان می‌دهند، تغییر پارامترهای مطرح‌شده نقش موثری در کاهش یا افزایش قابل‌ملاحظه تنش‌ها و جابجایی درام داشته و با تغییر در مقدار بارگذاری شعاعی، سرعت دورانی، ضخامت و انتخاب ماده fgm با ضریب غیر همگن مناسب بجای ماده همگن می‌توان درامی با سطح تنش‌های پایین‌تر و ضریب اطمینان بالاتر طراحی کرد.

investigation on effective factors in thermoelastic analysis of fgm rotating drum in air turbine engine under nonlinear thermal loading

in recent years, with the increasing growth of various industries, the development of advanced industrial structures has been widely increased in many industries such as aerospace, turbines, reactors, and other rotary machines. one of the most applicable rotating structures in this type is rotating drum in air turbine engines, which is very important due to the thermo-mechanical loads applied on it. the drum is a rotary structure that in recent years has been widely used in various sectors such as aerospace industries and nuclear facilities and has a very similar geometry to a thick-walled circular cylinder. this structure is under thermo-mechanical loads. analysis of rotating drum stresses and investigating effective parameters including loadings at inner and outer radius, rotating speed, and using advanced materials like fgms instead of homogenous materials is very important in the design of air turbine engine drums. a bunch of useful materials are fgm materials with a non-homogeneous coefficient which is suitable for redesigning a drum with lower stresses and higher safety factor. fgm materials are special types of composites and their properties can change steady and slowly in one or more arbitrary directions. these materials have high mechanical strength at high temperatures against applied loads, which makes them an appropriate selection in the above activity. in this paper, analyzing a rotary drum and investigation on effective parameters including rotating speed, types of loading carrying on internal and external surfaces, thickness, and type of material has been studied. in order to investigate the drum, a thermoelastic analytical solution is performed for both homogenous and fgm states under internal and external loading conditions. the material properties are assumed to vary nonlinearly in the radial direction and the poisson’s ratio is assumed constant. at first, differential equation of motion for fgm material is derived by assuming the properties functions exponentially and thermal gradients as an arbitrary function of radius. then the equation is solved analytically using matlab engineering software. stresses and displacements were calculated in clamp-clamp ends boundary conditions. then, the governing thermal differential equation of the drum was solved and the response was replaced with an arbitrary thermal function considered at first stage of the analysis. after calculating the displacements and stresses applied to drum for fgm and homogeneous states, a study on effective parameters was carried out. changes in the values of different parameters affecting the stresses and displacements, including rotation speed, magnitude, and type of loading on internal and external surfaces in the same working conditions on homogenous and fgm with non- homogeneous coefficients have been investigated. results clearly show the significant effects of loading conditions, drum rotating speed, and materials deployed to improve the drum behavior. to apply drum’s thermal distribution, the heat transfer function in steady-state conditions has been used. after calculating the displacement and stresses, the effect of various parameters which affect stresses and displacements, including rotating speed, types of loading carrying on internal and external surfaces, thickness, and type of material (non-homogeneous constants) have been investigated. also, the equivalent stress was obtained using von mises criteria. the results show that changing the values of noted affecting parameters has significant affection on stresses and displacements reduction and changing type of radial loadings, rotating speed, thickness and choosing fgm material with appropriate fg coefficients instead of homogeneous state can lead to design a drum with lower stresses and consequently higher safety factor.