Modeling the effective properties and thermomechanical behavior of SMA‐SMP multifunctional composite laminates

Abstract

The research work presents the modeling of effective properties and thermo‐mechanical behavior of shape memory fiber (SMF) and shape memory polymer (SMP) composite laminates using micromechanical approaches based on the method of mixtures (MOM) and method of cells (MOC). The fiber is made of a nickel‐titanium (Ni‐Ti) shape memory alloy (SMA), while the matrix consists of a shape memory thermoset epoxy polymer (SMP). The use of an SMP matrix provides large strain compatibility with the SMA fiber, while being active at high temperatures without losing its elastic properties. Additionally, the SMP matrix is also able to produce similar pseudoelastic and shape memory effects, which are noticed in SMAs. In the analysis, a two step homogenization scheme is followed. In the first step the effective properties of each layer are determined via a micromechanics approach with iso‐strain conditions. In the second step the effective properties of the SMF‐SMP composite are computed making a thin plate theory assumption, which takes into account the transverse shear deformations. The possible elastic couplings for SMF‐SMP laminates are discussed, and the laminate force and moment resultants are computed for various laminate configurations. The analysis takes into account the effects of phase transformations and the resulting change in the fiber–matrix modulus. The results have been compared by considering different fiber volume fractions, temperatures, fiber orientations, and lamina stacking sequences. The results show that adaptive SMA‐SMP composites laminates can be developed that provide shape controllability via tunable laminate stiffnesses leading to optimal response. Furthermore, the work presents the necessary framework for a reliable and efficient analysis of SMA‐SMP laminates for practical applications. The theory can be directly used in established plate and shell formulations of finite element analysis. Finally, the variations in force and moment resultants with respect to fiber orientations and stacking sequences are presented, which are useful to study the bending and buckling characteristics of active composites for shape control of adaptive structures. The work concludes that efficient adaptive laminate development for high performance composite applications, exhibiting large shape adaptivity, high stresses, and increased stiffness, are feasible as compared to SMA composites without active matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Review of Progress in Shape Memory Epoxies and Their Composites

“…Alternatively, a fractional model derived from the SLS model has been also introduced for the prediction of isothermal and non-isothermal free recovery processes of amorphous SMPs [ 226 ]. Macroscale constitutive modelling approaches have been also successfully applied for the description of various composites including e.g., SMA-SMEP [ 227 ] and carbon nanotube (CNT)-SMEP [ 135 ] combinations.…”

Modeling the Thermoviscoelastic Properties and Recovery Behavior of Shape Memory Polymer Composites

“…Many finite element modeling studies have been aimed at optimizing a material for device design, such as a SMPC hinge [15][16][17], These typically described the SMP matrix as a linear elastic material with a constant stiffness. Few studies have used computational and theoretical micromechanical models [18][19][20][21] to elucidate the underlying effects of the filler properties, shape, and volume fraction on the thermomechanical properties of SMPCs, These have been limited by their use of either linear thermoviscoelastic models [19,20] or rate-independent, small-strain, phase transition models [20,21] to describe the behavior of the SMP matrix, which can be highly nonlinear and time-dependent. Finite element analysis (FEA) models of the SMPC have also focused on investigating the effects of the reinforcements on the composite stiffness and shape fixity/recovery ratio, without studying their effects on the temperature dependence ofthe shape recovery response and viscoelastic properties [18,19], More recently, Westbrooke et al, [22] and Yu et al, [23] applied finite-deformation thermoviscoelastic models for the SMP matrix to examine the how the heating temperature and particle size infiuence the free recovery due to heat conduction of magneto-sensitive SMP composites.…”

Recent advances in shape memory epoxy resins and composites

“…Friedrich-1611165 978-0-323-26434-1 00027 with many challenges (optimum amount of SMA including its structuring, adhesion of SMA to the matrix, modeling the properties [65]). The future belongs to "active" SMEPs and related composites.…”