Numerical Simulations on Shape Memory Effect of Shape Memory Polymer

2010 ◽  
Vol 452-453 ◽  
pp. 465-468
Author(s):  
Bo Zhou ◽  
Shi Cheng Zhao ◽  
Hui Qi ◽  
Li Min Zhou
Keyword(s):  
Numerical Simulation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Polymer ◽  
Simulation Method ◽  
Mechanical Behaviors ◽  
Recoverable Strain ◽  
Finite Element Software ◽  
Numerical Simulation Method

Shape memory polymer (SMP) is being used in many engineering fields due to its shape memory effect and the advantages of large recoverable strain, excellent manufacturability, light weight, low cost and bio-degradability. Therefore it is of practical interest to investigate its thermo-mechanical behaviors. In this paper, a numerical simulation method is supposed to simulate the thermo-mechanical behaviors of SMP using the finite element software of MSC Marc, which is good at simulating the thermo-mechanical behaviors of viscous elastic material. The comparisons between the numerical results and the experimental results by Tobushi et al. illustrate the supposed numerical simulation method well describes the thermo-mechanical behaviors of SMP during the thermo-mechanical processes realizing shape memory effect.

A Viscoelastic-Plastic Constitutive Model of Shape Memory Polymer

2019 ◽  
Vol 35 (5) ◽  
pp. 601-611 ◽  
Author(s):  
Xueyao Zheng ◽  
Bo Zhou ◽  
Shifeng Xue
Keyword(s):  
Constitutive Model ◽  
Stationary Phase ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Polymer ◽  
Memory Process ◽  
Mechanical Behaviors ◽  
Reversible Phase ◽  
Flow Element

ABSTRACTIt is of practical significance to develop a constitutive model which is able to predict the thermomechanical behaviors of the shape memory effect occurring in a shape memory polymer (SMP) accurately. The mechanism of shape memory effect of SMP is explained based on the assumption that SMP is composed by two phases, reversible phase and stationary phase. Especially the different flow elements are respectively added to the reversible phase and stationary phase in order to express the plastic behavior of SMP. There are two springs in series, one dashpot and one flow element in the reversible phase. There are two springs in parallel, one dashpot and one flow element in the stationary phase. A constitutive equation is developed to express the thermo-mechanical behaviors of shape memory effect in the SMP based on viscous-elastic mechanics and plastic theory. An internal variable, frozen ratio, is defined to follow the shape memory process in SMP, and the material properties are described as the functions of frozen ratio based on phase transition theorem. The developed constitutive model, which includes above constitutive equation and material parameter functions, is used to numerically simulate the thermo-mechanical behaviors of SMP under various load cycles. Results show that the developed constitutive model can not only predict the shape memory process of SMP accurately, but also express the rate-dependent behaviors of SMP effectively.

Numerical Simulation of Vibration Control in Rotors Using Bearing with Shape Memory Effect

2008 ◽  
Author(s):  
Alexandre Luiz Amarante Mesquita ◽  
José Adriano Brito da Silva ◽  
Edson Paulo da Silva ◽  
Milton Dias
Keyword(s):  
Numerical Simulation ◽  
Shape Memory ◽  
Vibration Control ◽  
Shape Memory Effect ◽  
Memory Effect

Sintering and Morphology of Porous Structure in NiTi Shape Memory Alloys for Biomedical Applications

2012 ◽  
Vol 570 ◽  
pp. 87-95 ◽  
Author(s):  
Irfan Haider Abidi ◽  
Fazal Ahmad Khalid
Keyword(s):  
Elastic Modulus ◽  
Shape Memory Alloys ◽  
Porous Structure ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Biomedical Implants ◽  
Recoverable Strain ◽  
Porous Niti ◽  
Niti Shape Memory Alloys

The combination of attractive properties of porous NiTi shape memory alloys like high recoverable strain due to superelasticity and shape memory effect, good corrosion resistance, improved biocompatibilty, low density and stiffness along with its porous structure similar to that of bone make them best materials for biomedical implants. In current study porous NiTi SMAs have been fabricated successfully by space holder technique via pressureless sintering using NaCl powder as a spacer. Various volume fractions of NaCl powders have been involved to study their effect on the pore characteristics as well as on mechanical properties of foam. Porous NiTi with average porosity in the range of 44.3%-63.5% have been fabricated having average pore size 419µm which were very appropriate for various biomedical implants. Porous NiTi SMAs exhibited superelasticity at room temperature and shape memory effect was also determined. Maximum recoverable strain of 6.79% was demonstrated by the porous NiTi alloy with 44.3% porosity and it was diminishing with increasing porosity. Compression strength and elastic modulus have shown a decreasing trend with increasing porosity content. Elastic modulus of porous NiTi extends from 1.38 to 5.42GPa depending upon the pore volume which was very much comparable to that of various kinds of bones.

scholarly journals Fabrication and Two-Way Deformation of Shape Memory Composite with SMA and SMP

2010 ◽  
Vol 638-642 ◽  
pp. 2189-2194 ◽  
Author(s):  
Hisaaki Tobushi ◽  
Shunichi Hayashi ◽  
Y. Sugimoto ◽  
K. Date
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Polymer ◽  
Bending Deformation ◽  
Heating And Cooling ◽  
Round Shape ◽  
Heat Treated ◽  
Shape Memory Composite

The shape memory composite (SMC) with shape memory alloy (SMA) and shape memory polymer (SMP) was fabricated, and the two-way bending deformation and recovery force were investigated. The results obtained can be summarized as follows. (1) Two kinds of SMA tapes which show the shape memory effect and superelasticity were heat-treated to memorize the round shape, respectively. The shape-memorized round SMA tapes were sandwiched between the SMP sheets, and the SMC belt was fabricated. (2) The two-way bending deformation with an angle of 56 degrees is observed during heating and cooling. (3) If the SMC belt is heated and cooled by keeping the form, recovery force increases during heating and decreases during cooling.

Synthesis and Characterization of IPDI Based Shape Memory Polyurethane

2020 ◽  
Vol 1010 ◽  
pp. 142-147
Author(s):  
Nur Athirah Rasli @ Rosli ◽  
Syazana Ahmad Zubir
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Soft Segment ◽  
Shape Memory Polymer ◽  
Palm Kernel ◽  
Hexamethylene Diisocyanate ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Chain Flexibility

Various polyurethane-based shape memory polymer was synthesized using polycaprolactone (PCL) as soft segment and, hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IPDI) as the hard segments. Palm kernel oil-based polyol was used to replace part of the petroleum-based polyol due to the increasing demand on renewable resources as a result of environmental awareness. The synthesis has been carried out using two step polymerization method. The effects of varying the molar ratio of IPDI/HMDI on material properties such as crystallinity, transition temperature, morphology, shape memory effect and tensile strength were investigated by using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), shape memory test and tensile test. A high IPDI content in SMPU results in better shape memory effect, whereas increasing HMDI content leads to a better chain flexibility. In this work, the incorporation of IPDI contributes to the formation of phase separation which enhance the formation of crystalline soft segment structure while the incorporation of HMDI as isocyanate tend to promote phase mixing which enhance the chain flexibility of the SMPU backbone.

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