مدل سازي رفتار ماده مركب حاوي سيم حافظه دار با در نظرگرفتن تنش تماسي

چكيده انگليسي :

Modeling of SMA Composites Considering the Interfacial Stresses Amin Miramini a miramini@me iut ac ir 13th January 2015 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mahmoud Kadkhodaei kadkhodaei@cc iut ac irAbstractShape memory alloys SMA are a type of smart materials which are able to recover their original shape afterlarge deformations when heated above a certain temperature as a result of phase transformation Compositescontaining SMA wires are able to control their stiffness and vibrational properties modify their shape and repairexisting damages Due to these unique capabilities SMA composites are gaining interest in aerospace civilengineering and medical industries The interface between SMA wire and matrix plays an important role indetermining the effective response of the composites since it is the medium through which stress transfer occurs The mechanical behavior of these composites depends on the efficiency of the stress transfer between wire andmatrix during loading One of the most common types of failure in SMA wire reinforced composites is theinterfacial debonding between wire and matrix This type of failure in SMA composites may occur as a result ofover actuation of temperature or some kind of thermo mechanical loading In this study a 3 D finite element model of composites embedded with shape memory alloy wires is developedto predict interfacial debonding between SMA wire and matrix A bilinear cohesive zone model is used to defineinterfacial interaction between wire and matrix The cohesive zone model relates interfacial traction tointerfacial separation using traction separation laws In order to develop cohesive zone model in the commercialfinite element software ABAQUS the surface based cohesive technique is utilized Firstly this method isemployed to simulate interfacial debonding in a carbon fiber pull out test After validating the obtained resultsagainst the existing data from the literature the SMA fiber pull out is simulated To model SMA in ABAQUS a3 D phenomenological constitutive model based on the one developed by Boyd and Lagoudas is implementedinto ABAQUS using a user subroutine UMAT The influence of SMA fiber activation temperature on pull outdebonding force is then investigated by the model and the predictions are compared with existing results Thefindings confirm that debonding force increases with increasing temperature above austenite startingtemperature As In addition in this research a number of single wire pull out tests are performed on epoxycomposites embedded with steel wires and Nickel Titanium SMA wires and the influence of wire embeddedlength on pull out debonding force is investigated The results reveal that for steel wire with a relatively shortembedded length the debonding force increase with embedded length Moreover the results obtained fromSMA wire pull out tests indicate for SMA reinforcements that underwent a martensitic phase transformation the debonding force is approximately equivalent to the martensite transformation load In fact for SMA wire the considerable elongation associated with transformation leads to a significant lateral contraction thatfacilitates the debonding process In all the studied cases an acceptable agreement between experimentalfindings and simulation results ensures the validity of the proposed model to predict interfacial debondingbetween wire and matrix Finally the proposed method is utilized to analyze the interfacial debonding in atypical SMA wire reinforced composite It is suggested that the developed model can be used to predictinterfacial debonding between wire and matrix in different applications KeywordsShape memory alloy composites Finite element modeling Interfacial debonding Cohesivezone model Pull Out test

ميراميني، امين

مدل سازي رفتار ماده مركب حاوي سيم حافظه دار با در نظرگرفتن تنش تماسي

مواد مركب حاوي سيم حافظه دار , آلياژهاي حافظه دار , شبيه سازي اجزاي محدود , گسيختگي بين لايه اي , آزمون Pull-Out