نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناسی ارشد، مهندسی مکانیک، دانشگاه کاشان، کاشان.

2 استاد، مهندسی مکانیک، دانشگاه کاشان، کاشا ن.

10.22068/jstc.2022.542167.1755

چکیده

در این پژوهش اثرات سیکل حرارتی خستگی بر روی چقرمگی شکست و بیشینه نیرو در مود اول تورق کامپوزیتهای زمینه پلیمری به صورت تحلیلی و تجربی بررسی شده است. برای مطالعه تحلیلی و تجربی، بارگذاری حرارتی نمونههایی شبیه تیر یک سر گیردار با چیدمان 16 لایه تک جهته با استفاده از الیاف شیشه تک جهته و رزین اپوکسی ساخته شدند. نمونهها تحت سیکل حرارتی بین دو دمای 15 و 65 درجه سانتیگراد برای بارگذاری 50 تا 150 سیکل قرار گرفتند. یک گروه از نمونه های بدون بارگذاری حرارتی سیکلی، بعنوان گروه کنترل نیز مورد بررسی قرار گرفتند. در هنگام آزمایش و دریافت نتایج از دستگاه آزمون کشش، نمونهها با استفاده از روش برهمکنش تصاویر دیجیتالی دو دوربین به منظور اندازه گیری طول ترک و باز شدگی دهانه ترک اولیه به دقت مورد ارزیابی و مشاهده دقیق قرار گرفتند و نرخ رهایی انرژی کرنشی برای محاسبه چقرمگی شکست بحرانی از داده های تجربی مورد استفاده قرار گرفت. با استفاده از روش توالی تصاویر، پروفایل جدایش نوک پیشترک اولیه به دست آمد. قوانین المانهای ناحیه چسبناک برای مدل کردن دقیق نتایج آزمونهای تجربی در نرم افزار المان محدود آباکوس مورد استفاده قرار گرفت. بررسی تغییرات نیرو نشان داد که چقرمگی شکست بحرانی در مود اول تورق به شدت متاثر از پروسه خستگی حرارتی می باشد، و بصورت غیرخطی با بارگذاری سیکلی حرارتی کاهش می یابد.

کلیدواژه‌ها

عنوان مقاله [English]

Investigation of thermal fatigue effects on crack propagation and mode I delamination of multilayer laminated composites using digital image correlation

نویسندگان [English]

  • Behzad Moslemi-Abyaneh 1
  • Ahmad Reza Ghasemi 2

1 Department of Mechanical Engineering, University of Kashan, Kashan, Iran.

2 Department of Mechanical Engineering, University of Kashan, Kashan, Iran.

چکیده [English]

In this research, the influence of thermal cycling on the fracture toughness and maximum load in mode I delamination of polymer matrix composites (PMCs) is investigated experimentally and analytically. To eliminate the effect of the remote ply orientation on the fracture toughness during delamination initiation and propagation, double cantilever beam (DCB) specimens with a stacking sequence of [0]16 using uni-directional glass fibers and epoxy resin were considered. The specimens were thermal-cycled between 15°C and 65°C for 50-150 cycles. One group of uncycled specimens were tested at the commencement of the investigation as a control group. During the DCB test and receiving universal tensile machine results, the specimens were inspected by 2 real-time cameras to record the delamination length and initial crack tip opening displacement (ICTOD). The strain energy release rate (SERR) approach was used for obtaining the critical fracture toughness (GIC) from the experimental data. By employing the digital image correlation (DIC) method, the initial crack tip separation profile was obtained. The measured bridging laws were used with cohesive elements in ABAQUS commercial software to accurately model the delamination propagation in DCB specimens. Investigation of load variations revealed that critical fracture toughness in mode I of delamination is firmly affected by the thermal fatigue process.

کلیدواژه‌ها [English]

  • Delamination
  • Thermal cycling
  • double cantilever beam
  • Interlaminar fracture toughness
  • Laminated composite
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