A 3D constitutive model is proposed and verified with experimental data. Tension-torsion coupling effect and tension-compression asymmetry effect is investigate for tube shape memory alloy.
hi everyone,
i am doing my dissertation on buckling of channel section. so i have used abaqus software to do the analysis. i did the modelling and applided unit load n given pinned-pinned end condition. and i have used constraints to both ends such that the load applied on the edge is concentrated at a point .
but the results i.e mode shapes are not coming properly even the eigen values are very less compaired to calculated buckling load.
plz help me out.
dimensions of specimen channel section
width of web 100mm
width of flange 50mm
In this paper, a macroscopic model in a thermodynamically-consistent framework for shape memory alloys is proposed.
A soft ionic conductor can serve as an artificial nerve in an artificial muscle. A polyacrylamide hydrogel is synthesized containing a hygroscopic salt, lithium chloride. Two layers of the hydrogel are used as ionic conductors to sandwich a dielectric elastomer and fabricate a highly stretchable and transparent actuator. When the two layers of the hydrogels are subject to a voltage, the actuator reduces its thickness and expands. An areal strain of 134% is demonstrated.
Smart materials are designed to have a controlled response to external stimuli. Shape-memory polymers (SMPs) are one of the most well known classes of mechanically active smart materials and have experienced an incredible amount of research attention over the last decade. They are able to recover programmed deformations when heated above a thermal transition; however, are generally considered a one-time event. Liquid-crystalline elastomers (LCEs) are another class of actively moving polymers; however, these materials can demonstrate reversible and repeatable shape memory without the need for “re-programming” after each actuation cycle.
A pre-stretched dielectric elastomer is capable of large deformation, when subject to voltage. This paper investigates the effect of two types of pre-stretch: by strain and by stress. The difference is compared and discussed using thermodynamics models. The significance of the pre-stretch in actuation is explained by examining the true stress in actuation. Under both pre-stretch strategies, during the actuation, the dielectric elastomer exhibits hysteresis loops due to snap-through but differs in shape and physical quantity.
Dear all,
I am trying to formulate the return mapping algorithm with Hill48 yield condition, isotropic hardening law and flow rule referenced to Simo & Hughes (Computational Inelasticity).
In section 2.2.2.1, equation (2.2.9) expresses the Kuhn-Tucker complementarity conditions:
In addition to conditions (2.2.9), satisfies the consistency requirement:
Shape memory effect and pseudoelasticity behavior in tetragonal zirconia polycrystals: A phase field study, International Journal of Plasticity 60 (2014) 71–86. Martensitic tetragonal-to-monoclinic transformation in zirconia is a ‘‘double-edged sword’’, enabling transformation toughening or shape memory effects in favorable cases, but also cracks and phase degradation in undesirable scenarios.
In this study, we presented a numerically robust procedure to evaluate 4th order tangent moduli which are vital for acheiving quadratic convergence of global Newton-Raphson scheme.
In this study, the proposed method is verified for hyperelastic models alone. However, the same can be extended to other constitutive models.
The paper can be found at
Numerically approximated Cauchy integral (NACI) for implementation of constitutive models
10.1016/j.finel.2014.05.016
