The heating‐responsive shape‐memory effect (SME) based on melting in two thermoplastic polyurethanes (TPUs) with low melt‐flow index is experimentally investigated. It revealed that after severe deformation either tension or impression at room temperature, upon heating to the significant shape recovery achieved. underlying mechanism for (based melting) such a type of polymers without crosslinking proposed. This generic and should be applicable most index. image

This study presents a novel approach for predicting the location and fatigue life of degenerative intervertebral discs (IVDs) under cyclic loading conditions, aiming to improve understanding disc degeneration mechanisms. Based on mechanical theories linking IVD stress imbalance water loss, finite element (FE) model L4–L5 lumbar spine was developed, combining probability-weighted anatomical structures, inverse dynamics, cumulative mechanics. By quantifying variations calculating damage across...

The shape memory effect (SME) refers to the ability of a material recover its original shape, but only in presence right stimulus. Most polymers, either thermo-plastic or thermoset, can have SME, although actual performance varies according exact and how is processed. Vitrimer, which between thermoset thermo-plastic, featured by reversible cross-linking. Vitrimer-like polymers (SMPs) combine vitrimer-like behavior (associated with dissociative covalent adaptable networks) be utilized achieve...

A series of silicone based elastic shape memory hybrids are fabricated. Their performance, mechanical behaviors at room temperature with/without programming and during fitting 37 °C investigated. It is found that these materials have good effect always highly elastic. At °C, there 10 min or more for fitting. Thus, it concluded this type material has great potential as an comfort

The influence of programming strain and temperature on the shape memory effect surface morphology in programmed polycarbonate (PC) samples via uni-axial stretching is investigated. It found that at around glass transition start not only have micro-cracks their surface, but also show a necking phenomenon. Furthermore, necked area concave, non-necked convex. On other hand, despite high temperatures being able to deform uniform manner macroscopic scale, surfaces are still uneven, either concave...

Porous shape memory hybrids are fabricated with different matrix (silicone) hardness and inclusion (polycaprolactone, PCL) ratios. They characterized to obtain their mechanical response cyclic loads (with/without pre-straining/programming) performances after body-temperature programming investigated. These materials lightweight due porous structures. Wetted hydrogels used in the fabrication process for creating pores reusable hence this is eco-friendly. exhibit good effect of around 90%...

Abstract Elastic/acoustic metamaterials with local resonance (LR) arrays have bandgaps that can forbid or suppress the propagation of elastic waves. In this paper, shape memory alloy (SMA) is utilized in metamaterial structure to yield variable bandgaps. The relationship between LR bandgap and temperature during heating cooling obtained using a beam periodic array SMA resonators, effect pre-tension on SMA-based explored. experimental results show varies along variation. However, as modulus...

The nonlinear, in-plane mechanics of a thin-walled honeycomb with zero Poisson's ratio under large deformation is investigated in this paper. A theoretical method for calculating tensile modulus, modified factors linear constitutive relations the structures proposed based on theory Euler-Bernoulli beam and bending deflection, finite element simulation given to validate. In addition, parametric analysis revealing impacts geometrical configurations material parameters mechanical properties...

ABSTRACT In this article, we reveal the temperature memory effect (TME) in a commercial thermoplastic polymer, namely ethylene‐vinyl acetate (EVA), within its glass transition range via series of differential scanning calorimeter (DSC) tests. addition, investigate influence heating holding time and also compare observed TME current study with that shape alloys (SMAs). It is concluded DSC (without any macroscopic change) achievable polymer. Conversely, although shares many similar features as...

In this paper, first we investigate the heating-responsive shape memory effect in an acrylonitrile butadiene styrene (ABS). Subsequently, after surface treatment (via dipping acetone/water solution of different concentrations and for time) pre-stretched samples, demonstrate feasibility to form strip shaped wrinkles atop upon heating ABS recovery. The influential factors, such as acetone concentration time treatment, are revealed discussed.

Abstract Shape memory materials can be utilized to realize fast shape customization for personalized comfort fitting experiences. In this paper, a series of body-temperature programmable elastomers are developed fitting. Unlike the reported ones, in which switch is realized due phase transition (around 37 °C), these newly ones fabricated with silicone rubber (as elastic component) and kind polycaprolactone (PCL, as that has melting point about 56 °C much lower crystallization temperature....

In this study, finite element (FE) models of an anatomical normal and a degenerated disc L4–L5 motion segment, developed using different methodologies volume mesh constructions, ways defining the spinal components’ material properties, were exercised analyzed. The geometrics details obtained digitizing technique segmentation computed tomography (CT) scans; with structural properties components defined based on literature greyscale values CT images for segments, respectively. predicted...

During the water entry process of a trans-domain morphing aircraft, significant impact forces are generated when aircraft hits surface, which will potentially cause deformation cabin structure and might damage or onboard devices. Thus, it is necessary to investigate structure. This paper analyses changes in fluid loads corresponding structural responses during process. Firstly, numerical model established for modeling method validated by comparing results experimental data. An empirical...

Tan Delta reflects the viscoelastic behavior of materials, particularly polymers. In most cases, a high value is associated with transitions (such as glass transition or melting), enabling effective damping properties near these temperature ranges. However, achieving over broad range challenging, for engineering applications that involve significant fluctuations. This paper presents straightforward method using layered composites, where polymer layer sandwiched between two highly stretchable...

In this paper, a thermo-responsive shape memory effect in polyvinyl chloride thermoset foam is characterized. Excellent recovery performance observed samples programmed both at room temperature and above their transition temperature. The conversion of porous structures the from closed-cell to open-cell after cycle revealed via series specially designed oil-dripping experiments optical images micro pores. Programming strain higher than 20% results an apparent increase level, whereas...