نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا، مهندسی هوافضا- سازه‌های هوایی، دانشگاه صنعتی مالک اشتر، تهران، ایران

2 دانشیار، مهندسی هوا فضا، دانشگاه صنعتی مالک اشتر، تهران، ایران

چکیده

اتصال ها به علت حساسیت بیشتر در برابر انتقال بار، تمرکز تنش و ناهمگونی جنس، هندسه و شرایط مرزی، یکی از مهم‌ترین و حساس‌ترین اجزا در سازه‌های کامپوزیتی هستند. اتصال‌های T شکل یکی از انواع پرکاربرد اتصال‌های کامپوزیتی محسوب می‌شوند. افزایش استحکام و ارتقای خواص دینامیکی اتصال به عنوان یکی از مهم‌ترین رویکردهای مهندسی در حوزه‌ی اتصال‌ها مطرح بوده است. در این مقاله به بررسی تاثیر پلکانی کردن رفتار ناحیه‌ی اتصال بر اساس رفتار تابعی آن روی رفتار دینامیکی اتصال پرداخته شده است. اتصال T شکل در نظر گرفته شده با اجزای اتصال ساندویچی با رویه‌های کربنی، به عنوان اجزای اتصال و چسب اپوکسی لاکتایت 3422 برای اتصال بین اجزای اتصال مدل‌سازی شده است. تحلیل مودال اتصال و آنالیز رفتار دینامیکی اتصال تحت بار نیم- سینوسی گذرا در نرم افزار المان محدود ABAQUS 6.12 انجام شده است. نتایج عددی برای ارزیابی پنل کامپوزیتی با نتایج تجربی انجام شده توسط نویسند‌گان و صحت فرایند طراحی اتصال T شکل برای ارزیابی رفتار دینامیکی، با نتایج عددی ارائه شده در مراجع مقایسه و تایید شده است. یکی از راه‌کارهای نوین برای بهبود رفتار دینامیکی اتصال، استفاده کردن از ناحیه‌ی اتصال پلکانی است. مشاهده شدن 34% تغییر در فرکانس طبیعی اول و همچنین تغییر شکل مودهای ارتعاشی از نتایج قابل توجه این تحقیق است. پاسخ ارتعاشی سازه به بار دینامیکی گذرا، در وضعیتی که از تقویت پلکانی استفاده شود، میرایی سازه‌ای بیشتری را نشان می‌دهد. همچنین نشان‌داده شده است که تغییر توپولوژی پلکانی اتصال، تاثیر قابل توجهی در جابجایی بیشینه‌ی تحت بار دینامیکی دارد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Numerical and experimental analysis of dynamical behavior of composite T-joint with step wise graded adhesive zone based on functional behavior model

نویسندگان [English]

  • Majid Mokhtari 1
  • Morteza Shahravi 2

1 Department of Aerospace Engineering, Malek-e-Ashtar University of technology, Tehran, Iran

2 Department of Aerospace Engineering, Malek-e-Ashtar University of technology, Tehran, Iran

چکیده [English]

Due to stress concentration, adherends non-homogeneity (adherends materials, geometry and boundary conditions), and load transferring phenomenon, joints are the most critical locations in the structures especially composite structures. Enhance the strength of the adhesive joints and improve the dynamic behavior of the joints are the main goal of the most adhesive joints studies during the last decade. The effect of the step graded behavior of adhesive zone on dynamic behavior of composite T- joint is studied in present work. Finite element analysis (FEA) of carbon fiber reinforced polymer (CFRP) face-sheets, presented with ABAQUS 6.12-1 FEM code software. Loctite Hysol 3422, an epoxy adhesive, selected to bonding purpose and step wise behavior of adhesive region. Modal analysis and transient half-sine dynamic response of the composite T- joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of manufactured sandwich panels and T-joint modeling. Step wise graded adhesive zone is a brilliant recommendation to control and improve the dynamic behavior of T-joints. The effect of the step wise graded adhesive zone on natural frequencies and mode shapes and transient response are compared for different topology of the step wise graded adhesive zone. It has been shown that the step wise graded adhesive zone cases changed the first natural frequency in range of 34 % and affected the mode shapes. Also the structural damping of the step wise graded adhesive zone cases and dynamic responses are smoother and more applicable.

کلیدواژه‌ها [English]

  • Composite T-joints
  • Step Graded Adhesive Zone
  • Dynamic Behavior
  • Transient Loading
  • modal analysis
[1]
Tsai, Chon L. and Kim, Dong S., "Analysis Of Fatigue Crack Propagation Behavior In Fillet Welded T-Joint" Engineering Fracture Mechanics, Vol. 36, No. 4, pp. 653-660, 1990.
[2]
Shenoi, RA. and Violette, FLM., "A Study Of Structural Composite Tee Joints In Small Boats" Journal Of Composite Materials, Vol. 24, No. 6,  pp. 644-666, 1990.
[3]
Guo, S. and Morishima, R., "Design, Analysis And Testing Of Sandwich T-Joint Structures" 50 th AIAA/ASME/ASCE /AHS/ASC Structures, Structural Dynamics, and Materials Conference 17th, California, Palm Springs, 2009.
[4]
May, M. Ganzenmüller, G. Wolfrum, J. Heimbs, S., "Analysis Of Composite T-Joint Designs For Enhanced Resistance To Hydrodynamic Ram"  Composite Structures, Vol. 125, pp. 188-194, 2015.
[5]
Theotokoglou, E.E., "Analytical Determination Of The Ultimate Strength Of Sandwich Beams" Applied Composite Materials,Vol. 3, No. 5, pp. 345-353, 1996.
[6]
Adams, R.D. Comyn, J. Wake, W.C., "Structural Adhesive Joints In Engineering", Springer Science & Business Media, 1997.
[7]
Kesavan, A., John, S., Herszberg, I., "Strain-Based Structural Health Monitoring Of Complex Composite Structures" Structural Health Monitoring, Vol.75, No. 1, pp. 313-320, 2008.
[8]
Whittingham, B. Li, H. Herszberg, I.  Chiu, W., "Disbond Detection In Adhesively Bonded Composite Structures Using Vibration Signatures" Composite Structures, Vol. 75, No. 1, pp. 351-363, 2006.
[9]
Davies, G.A.O. Ankersen, J., "Virtual Testing Of Realistic Aerospace Composite Structures"  Journal of Materials Science, Vol 43, No. 20, pp. 6586-6592, 2008.
[10]
Panigrahi, S.K., Pradhan, B., "Delamination Damage Analyses Of FRP Composite Spar Wingskin Joints With Modified Elliptical Adhesive Load Coupler Profile"  Applied Composite Materials, Vol. 15, pp. 189-205, 2008.
[11]
Khalili, S.M.R. Ghaznavi, A., "Numerical Analysis Of Adhesively Bonded T-Joints With Structural Sandwiches And Study Of Design Parameters"  International Journal of Adhesion and Adhesives, Vol. 31, No. 5, pp. 347-356, 2011.
[12]
Akpinar, S. Aydin, M.D. Temiz, Ö., "Non-Linear Stress Analysis On The Adhesively Bonded T-Joints With Embedded Supports" Composites Part B: Engineering, Vol. 53, pp. 314-323, 2013.
[13]
Park, Y.B. Lee, B.H. Kweon, J.H. Choi, J.H. Choi, I.H., "The Strength Of Composite Bonded T-Joints Transversely Reinforced By Carbon Pins" Composite Structures, Vol. 94, No. 2, pp. 625-634, 2012.
[14]
Stickler, P.B. Ramulu, M., "Experimental Study Of Composite T-Joints Under Tensile And Shear Loading" Advanced Composite Materials, Vol. 15, No. 2, pp. 193-210, 2006.
[15]
Stickler, P.B. Ramulu, M. Johnson, P.S., "Experimental And Numerical Analysis Of Transverse Stitched T-Joints In Bending" Composite Structures, Vol. 50, No. 1, pp. 17-27, 2000.
[16]
Nimje, S.V. Panigrahi, S.K., "Design And Analysis Of Functionally Graded Adhesively Bonded Double Supported Tee Joint Of Laminated FRP Composite Plates Under Varied Loading" Journal of Adhesion Science and Technology, Vol. 29, pp. 1951-1970, 2015.
[17]
Nimje, S.V. Panigrahi, S.K., "Interfacial Failure Analysis Of Functionally Graded Adhesively Bonded Double Supported Tee Joint Of Laminated FRP Composite Plates" International Journal of Adhesion and Adhesives, Vol. 58, pp. 70-79, 2015.
[18]
Apalak, M.K. Gunes, R., "Investigation Of Elastic Stresses In An Adhesively Bonded Single Lap Joint With Functionally Graded Adherends In Tension" Composite structures, Vol. 40, No. 4, pp. 444-467, 2005.
[19]
Gunes, R. Apalak, M.K. Yildirim, M., "The Free Vibration Analysis And Optimal Design Of An Adhesively Bonded Functionally Graded Single Lap Joint" International Journal of Mechanical Sciences, Vol. 49,No. 4, pp. 479-499, 2007.
[20]
Andrés, L., "Functionally Graded Joints by Dielectric Heating" MSc Thesis, University of Porto , 2013.
[21]
Carbas, R.J.C., "Adhesively Bonded Functionally Graded Joints" Ph.D Thesis,  Porto,  PORTO University, 2013.
[22]
Carbas, R.J.C. da Silva, L.F.M. Critchlow, G.W., "Adhesively Bonded Functionally Graded Joints By Induction Heating" AB2013,  Porto, 2014.
[23]
Khalili, S.M.R. Shariyat M. Mokhtari, M., "Static Tensile And Transient Dynamic Response Of Cracked Aluminum Plate Repaired With Composite Patch – Numerical Study" Applied Composite Materials, Vol. 21, pp. 441-455, 2014.
[24]
Khalili, S.M.R. Mokhtari, M., "Numerical Study of Adhesive Single-Lap Joints with Composite Adherends Subjected to Combined Tension–Torsion Loads,” The Journal of Adhesion, pp. 214-234 , 2013.
[25]
Hashin, Z., "Failure Criteria For Unidirectional Fiber Composites" Journal of applied mechanics, Vol. 7.2, pp. 329-334, 1980.
[26]
Olmedo, Á. Santiuste, C., "On The Prediction Of Bolted Single-Lap Composite Joints" Composite Structures, Vol. 94,  pp. 2127-2110, 2012.
[27]
Pilipchuk, V. Grace, I. Ibrahim, R. Ayorinde, E., "Structural Health Monitoring of Composite T-Joints Based on Distributed Effects of Localized Damages" 11th International Conference on Fast Sea Transportation FAST 2011, Honolulu, Hawaii, USA, September 2011.
[28]
Mokhtari, M., Salari, M. Abdoli, H. "Design and Manufacturing of Engineering Model of GEO Satellite Ku Band Antenna-Structual Design Reportation" Technical Report,  Shahid Ghandi Center of Research, Iran, 2014. (In Persian)