27543

بررسي تاثير آلياژهاي حافظه¬دار بر روي واپيچش در كامپوزيت¬هاي پليمري لايه¬اي

كارشناسي ارشد

مهندسي مكانيك - طراحي كاربردي - جامدات

1398/1401

1401/06/30

دكتر محمودمهرداد شكريه

مهندسي مكانيك

واپيچش ، پديده¬اي است كه در اثر اختلاف خواص حرارتي لايه¬ها، در چندلايه¬هاي كامپوزيتي رخ مي¬دهد و در بسياري موارد ناخواسته است. در اين مطالعه، با استفاده از آلياژ حافظه¬دار ، واپيچش در چندلايه كربن اپوكسي متعامد نامتقارن [08/908]، كاهش داده شد. از سيم SMA براي ايجاد نيروي فشاري در چندلايه كامپوزيت استفاده شد. سيم¬هاي حافظه¬دار با پيش¬كرنش 5% حين ساخت در ميان چندلايه¬ها قرار گرفتند؛ پس از تكميل پخت، با فعال¬سازي سيم¬ها، يك نيروي فشاري در چندلايه توليد شد كه باعث كاهش واپيچش نمونه¬ها شد. در ادامه، واپيچش نمونه¬ها به-كمك CMM اندازه‌گيري شد. با استفاده از كد يومت در نرم¬افزار المان محدود آباكوس، واپيچش نمونه¬ها شبيه¬سازي شد. پارامتر¬هاي تاثيرگذار بر واپيچش، ازجمله خواص مكانيكي و حرارتي سيم¬ها و چندلايه كامپوزيتي بررسي شد؛ بدست آوردن نتايج دقيق و درست، مسلتزم بررسي دقيق پارامترهاي مؤثر و طراحي مهندسي شده قطعات مجهز به سيم¬هاي حافظه¬دار است. نتايج بدست آمده از سه نمونه [08/908]، [01/wire/07/908] و [02/wire/06/908]، بيانگر 43% كاهش واپيچش در نمونه [01/wire/07/908] نسبت به نمونه بدون سيم و 29% كاهش واپيچش در نمونه [02/wire/06/908] مي¬باشد. مشخص شد كه از پارامترهاي مورد بررسي، محل قرار گرفتن سيم ها، تعدادشان و ميزان پيش¬كرنش، بيشترين تاثير را بر كاهش پديده واپيچش در چندلايه¬¬هاي كامپوزيت دارد.

1401/09/28

Investigation of the effect of shape memory alloys on warpage in polymer composite laminates

9/21/2023 12:00:00 AM

Warpage is caused by differences in mechanical and thermal properties and by residual stresses of layup in polymeric laminated composites, and in many cases it is unwanted. This study used shape memory alloy wires (SMA) to modify the fabrication process to reduce warpage in unsymmetric cross-ply [08/908] carbon-epoxy laminated composites. SMA wires were used to create compressive stress at a specific geometry in the laminates. During the fabrication of the specimens, shape-memory wires with 5% pre-strain were inserted in the layup. Due to the asymmetry of the laminate, the specimens were deformed after curing. After activating the wires by electrical current, a compressive force was induced in the laminate. This force reduced the warpage of the specimens. A coordinate measuring machine (CMM) was used to measure the amount of warpage of the specimens after the wires were activated. In addition, using a U-Mat code in the Abaqus finite element software, the warpage of laminated composites with SMA wires and without SMA wires was simulated and examined. The results of the simulation and experiments were in good agreement. Using simulation, the effective parameters on warpage, including mechanical and thermal properties of laminated composites, and wires were investigated. As a result of tests performed on specimens [08/908], [01/wire/07/908], and [02/wire/06/908], an improvement in warpage was observed by 43% in the [01/wire/07/908] specimen, and by 29% in the [02/wire/06/908] specimen, compared with the specimen without wires. Also, this modification of the fabrication process will reduce the residual stress in laminated composites. There were no significant differences between the results of FEM and experiments. In addition, it was considered that the geometry of embedded wires in laminate has a significant effect on the warpage in composite laminates. inserting wires at the farthest distance from the neutral plane of the specimen shows the most effectiveness in reducing the warpage.

كامپوزيت هاي چندلايه , تنش پسماند حاصل از پخت , واپيچش , كامپوزيت نامتقارن , آلياژ حافظه دار

warpage , laminated composites , shape memory alloy , coordinate measuring machine

Morteza Seyednejad

M.M.Shokrieh