ORALS

SESSION: ManufacturingWedPM1-R1 Non-Ferrous Advanced Materials from Macro- to Nanoscale - II	Mamalis International Symposium on Advanced Manufacturing of Advanced Materials and Structures with Sustainable Industrial Applications
Wed Nov, 7 2018 / Room: Mar Azul (50/1st)
Session Chairs: Tahir Cagin; Session Monitor: TBA

15:15: [ManufacturingWedPM108]
Modelling Shape Memory Effect in Hybrid Composite
Lucas Vignoli¹ ; Marcelo Amorim Savi¹ ; ¹Federal University of Rio de Janeiro, Rio de Janeiro, Brazil;
Paper Id: 360 [Abstract]

Composite materials have been widely used in a large range of industrial applications, mainly because of their lightweight characteristics and high capability to increase strength and stiffness in certain directions, especially in unidirectional laminates. On the other hand, the unique thermomechanical behavior of Shape Memory Alloys (SMAs) has a set of remarkable properties resulting from microscopic phase transformation, allowing the possibility to design new devices that consider pseudoelasticity and shape memory effect (SME) [1,2]. In this study, a unidirectional composite made by SMA fibers embedded in an epoxy matrix is considered. Two different temperature cycles are modelled: first, the curing manufacture process is simulated [3], and then the applied temperature on the SMA fibers to induce the SME. The generalized plane strain state is assumed, and two approaches are used to model the interaction between fibers and matrix. A simplified 1D model, which considers fibers and matrix as springs in parallel, is introduced to evaluate the maximum recovery capability of the composite and a 2D equivalent cell model is used to represent a hexagonal array [4]. The Brinson constitutive model [5] and its modified version with the von Mises equivalent for general stress state [6,7] are applied for the SMA fibers, while the matrix is assumed linearly-elastic with properties defined as functions of the temperature. The maximum recoverable strain range is found to be function not only of the SMA maximum recoverable strain but also of the matrix and interface failures [8]. Results indicate a good correlation between both approaches, however the 2D model has the advantage to be able to computer interface stresses and nonuniform phase transformation. A comparison with the analytical single-fiber model is also carried out [9].

References:
[1] D.D.A. Costa, M.A. Savi, (2017), "Nonlinear dynamics of an SMA-pendulum system", Nonlinear Dynamics, 87, 1617-1627. \n[2] P.B.C., Leal, M.A. Savi, (2018), "Shape Memory Alloy-Based Mechanism for Aeronautical Application: Theory, Optimization and Experiment", Aerospace Science and Technology, 76, 155-163.\n[3] J.B. Berman, S.R. White, (1996), "Theoretical modelling of residual and transformational stresses in SMA composites", 5, 731-743.\n[4] A.B. Morais, (1996), "Modelling Lamina Longitudinal Compression Strength of Carbon Fibre Composite Laminates", Journal of Composite Materials, 30, 1115-1131.\n[5] L.C. Brinson, (1993), "One dimensional constitutive behavior of shape memory alloys: themomechanical derivation with non-constant material functions and redefined martensite internal variable", Journal of Intelligent Material Systems and Structures, 4, 229-242.\n[6] D. Lagoudas, D. Hartl, Y. Chemisky, L. Machado, P. Popov, (2012), "Constitutive model for the numerical analysis of phase transformation in polycrystalline shape memory alloys", International Journal of Plasticity, 32, 155-183.\n[7] S. Enemark, I.F. Santos, M.A. Savi, (2016), "Modelling, characterisation and uncertainties of stabilised pseudoelastic shape memory alloy helical springs", Journal of Intelligent Material Systems and Structures, 27, 2721-2743. \n[8] Y. Huang, L. Xu, S.K. Ha, (2012), "Prediction of three-dimensional composite laminate response using micromechanics of failure", Journal of Composite Materials, 46, 2431-2442. \n[9] Y. Wang, L. Zhou, Z. Wang, H. Huang, L. Ye, (2011), "Analysis of internal stresses induced by strain recovery in a single SMA fiber-matrix composite", Composites: Part B, 42, 1135-1143.

SESSION: ManufacturingWedPM2-R1 Non-Ferrous Advanced Materials from Macro- to Nanoscale - III	Mamalis International Symposium on Advanced Manufacturing of Advanced Materials and Structures with Sustainable Industrial Applications
Wed Nov, 7 2018 / Room: Mar Azul (50/1st)
Session Chairs: Vladimir Kirko; Session Monitor: TBA

16:20: [ManufacturingWedPM210]
Damage Modeling of Shape Memory Alloys
Vanderson Marcio Dornelas¹ ; Sergio Almeida Oliveira² ; Marcelo Amorim Savi¹ ; ¹Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; ²Centro Federal de Educação Tecnológica Celso Suckow da Fonseca (CEFET/RJ), Rio de Janeiro, Brazil;
Paper Id: 361 [Abstract]

Shape memory alloys (SMAs) belong to smart materials being employed in several kinds of applications [1]. Modeling and simulations are essential issues to be considered for proper designs of these systems. In this regard, fatigue phenomenon is a special subject that needs to be investigated. In general, SMAs exhibit two kinds of fatigue: functional fatigue, related to the decrease of the functional properties; and structural fatigue, that is characterized by the nucleation and growth of microcracks which can lead to fracture [2]. This paper discusses a macroscopic three-dimensional constitutive model that describes functional fatigue in shape memory alloys. Comparisons between numerical and experimental uniaxial results are performed for the validation of the proposed model. In addition, general numerical simulations are presented in order to explore the general thermomechical behavior of SMAs.

References:
[1] M.A. Savi, A. Paiva, A.P. Baota-Neves, Journal of Intelligent Material Systems and Structures 13 (2002) 261-273.
[2] G. Eggeler, E. Hornbogen, A. Yawny, M. Wagner, Materials Science and Engineering 378 (2004) 24-33.