8262

7660

كارشناسي ارشد

طراحي كاربردي

اصفهان:دانشگاه صنعتي اصفهان، دانشكده مكانيك

1392

پانزده، 93ص: مصور، جدول، نمودار

ص.ع.به: فارسي و انگليسي

محمدرضا فروزان

سعيد ضيايي راد

24/09/1392

محمود كدخدايي، مهدي سلماني تهراني

مهندسي مكانيك

ID7660

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

Investigating the Axial Buckling Strength of Pultruded Composite Beams After Axial Impact Loading Manizheh Aghaei manizheh aghaei@me iut ac ir Date of submission 2013 09 11 Department of mechanical engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Mohammad Reza Forouzan forouzan@cc iut ac irAbstractSince many years ago composite materials have been selected as a replacement for some metals such as Steeland Aluminum in many industries due to their high strength to weight ratio high corrosion resistance andmany other features Composite beams are such products of composites that are being used in buildingconstructions roads bridges etc Impact is an important subject in composite materials Because impactdamage reduce their strength One type of impact that may be applied to composite beams is axial impact whichvery little work on it has been published Investigating residual axial buckling strength of beams after impact isso important because by the sudden buckling instability of beams the entire structure may become unstable andcollapse In this research glass polyester channel section beams made by pultrusion method initially placedunder axial impact and then residual axial buckling strength of beams after impact has been measured In orderto investigate the effect of impact damage on the residual axial buckling strength of beams axial strength ofundamaged beams has been also measured Simulation of the problem has been done in the finite elementsoftware ABAQUS Explicit and in order to investigate damage initiation the four failure criteria of maximumstress maximum strain Hashin and Hou have been compared with each other In addition to these failurecriteria which are simple and well known instantaneous damage evolution law has been used For modeling ofdamage and defining material behavior of orthotropic user subroutine VUMAT is used Experimental tests havebeen performed to validate numerical results and simulation with related tests have been done for variousconditions In this case the effect of weight and height of the impactor and also length of the beam have beenconsidered By comparing the results of simulation and experiment it was concluded that for axial compressionof undamaged beams maximum stress maximum strain and Hashin failure criteria have had the best predictionfor force displacement and buckling mode while Hou failure criteria have predicted much damage in the beamand the results of this criteria have been cautiously For compression after impact maximum stress and Hashinfailure criteria have had similar results and also consistent with the experimental results Also with the help ofresearch undertaken in this thesis this result has been achieved that depending on the type of material used andloading and boundry conditions Appropriate failure criteria should be used to model damage and then bysimulating with this failure criteria it would be simple to achieve results that would not be easy to get themthrough the test for example buckling mode and damage mode shapes KeywordsPultruded beam axial impact residual axial buckling strength FEM VUMAT experiment

محمدرضا فروزان

سعيد ضيايي راد

محمود كدخدايي، مهدي سلماني تهراني