Manufacturing of a Shape Memory Polymer Actuator

Author(s):  
Loredana Santo ◽  
Giovanni Matteo Tedde ◽  
Fabrizio Quadrini

Shape memory polymer (SMP) foams can be used to manufacture actuators with tailored actuation rate. Being related to foam shape recovery by heating, SMP actuator operates by conversion of heat into motion. In the current study, a SMP linear actuator has been manufactured which is able to apply a maximum load of 50 N (depending on the recovery temperature) and a maximum stroke up to 30 mm. The actuator had a cylindrical shape and its piston had a diameter of 16 mm, therefore a maximum applied pressure about 2.5 bar. The active element (i.e. SMP foam) was produced by solid state foaming of an epoxy resin, and its shaping was performed in the same metallic frame of the actuator. Results show that small and medium-size actuators can be easily produced and operated.

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3754
Author(s):  
Seokwoo Nam ◽  
Eujin Pei

Four-dimensional printing (4DP) is an approach of using Shape Memory Materials (SMMs) with additive manufacturing (AM) processes to produce printed parts that can deform over a determined amount of time. This research examines how Polylactic Acid (PLA), as a Shape Memory Polymer (SMP), can be programmed by manipulating the build parameters of material extrusion. In this research, a water bath experiment was used to show the results of the shape-recovery of bending and shape-recovery speed of the printed parts, according to the influence of the print pattern, infill density and recovery temperature (Tr). In terms of the influence of the print pattern, the ‘Quarter-cubic’ pattern with a 100% infill density showed the best recovery result; and the ‘Line’ pattern with a 20% infill density showed the worst recovery result. The ‘Cubic-subdivision’ pattern with a 20% infill density demonstrated the shortest recovery time; and the ‘Concentric’ pattern with a 100% infill density demonstrated the longest recovery time. The results also showed that a high temperature and high infill density provided better recovery, and a low temperature and low infill density resulted in poor recovery.


2010 ◽  
Vol 24 (15n16) ◽  
pp. 2351-2356 ◽  
Author(s):  
YAN-JU LIU ◽  
XIN LAN ◽  
HAI-BAO LU ◽  
JIN-SONG LENG

Smart materials can be defined as materials that sense and react to environmental conditions or stimuli. In recent years, a wide range of novel smart materials have been developed in biomaterials, sensors, actuators, etc. Their applications cover aerospace, automobile, telecommunications, etc. This paper presents some recent progresses in polymeric smart materials. Special emphasis is laid upon electroactive polymer (EAP), shape memory polymer (SMP) and their composites. For the electroactive polymer, an analysis of stability of dielectric elastomer using strain energy function is derived, and one type of electroactive polymer actuator is presented. For the shape memory polymer, a new method is developed to use infrared laser to actuate the SMP through the optical fiber embedded within the SMP. Electrically conductive nanocarbon powders are utilized as the fillers to improve the electrical conductivity of polymer. A series of fundamental investigations of electroactive SMP are performed and the shape recovery is demonstrated.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1275 ◽  
Author(s):  
Guido Ehrmann ◽  
Andrea Ehrmann

Poly(lactic acid) is not only one of the most often used materials for 3D printing via fused deposition modeling (FDM), but also a shape-memory polymer. This means that objects printed from PLA can, to a certain extent, be deformed and regenerate their original shape automatically when they are heated to a moderate temperature of about 60–100 °C. It is important to note that pure PLA cannot restore broken bonds, so that it is necessary to find structures which can take up large forces by deformation without full breaks. Here we report on the continuation of previous tests on 3D-printed cubes with different infill patterns and degrees, now investigating the influence of the orientation of the applied pressure on the recovery properties. We find that for the applied gyroid pattern, indentation on the front parallel to the layers gives the worst recovery due to nearly full layer separation, while indentation on the front perpendicular to the layers or diagonal gives significantly better results. Pressing from the top, either diagonal or parallel to an edge, interestingly leads to a different residual strain than pressing from front, with indentation on top always firstly leading to an expansion towards the indenter after the first few quasi-static load tests. To quantitatively evaluate these results, new measures are suggested which could be adopted by other groups working on shape-memory polymers.


2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).


2013 ◽  
Vol 4 (3) ◽  
pp. 167-178 ◽  
Author(s):  
Fei Liang ◽  
Robert Sivilli ◽  
Jihua Gou ◽  
Yunjun Xu ◽  
Bob Mabbott

Author(s):  
Mohammadhadi Hosseinzadeh ◽  
Majid Ghoreishi ◽  
Keivan Narooei

In this paper, the effects of thermal parameters including the deformation temperature, shape recovery temperature, and heating rate on the shape recovery of a specific rounded rectangle structure were investigated using the design of experiments. Three-point bending thermo-mechanical tests were subsequently carried out where water was used for controlling the temperature. It was found that the deformation temperature and heating rate have the most and the least effect on the shape recovery of polylactic acid (PLA) SMPs, respectively. The mathematical modeling results showed that the optimum condition of the highest shape recovery is obtained at the deformation temperature of 53.31°C, recovery temperature of 59.94°C, and heating rate of 8.05°C/min. It was also observed that the shape recovery of the specified rounded rectangle structure manufactured by the 3D printing method was enhanced from 93.03% to 98.14% by optimizing the thermal parameters. Besides, the optimum condition was applied to structures with different cell geometries and it was shown that the obtained condition was also enhanced the shape recovery of structures with diamond and honeycomb. More specifically, the shape recovery of noted structures was significantly enhanced to 98.00% and 97.71 % from 82.86% and 78.89%, respectively.


2013 ◽  
Vol 705 ◽  
pp. 169-172
Author(s):  
Xue Feng ◽  
Li Min Zhao ◽  
Xu Jun Mi

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.


2019 ◽  
Vol 30 (17) ◽  
pp. 2639-2647
Author(s):  
O-Hyun Kwon ◽  
Jin-Ho Roh

A sandwiched morphing structure is developed using an Origami-inspired shape memory dual-matrix composite core and shape memory polymer composite skins. The geometric parameters of the morphing structure are designed to have a zero Poisson’s ratio. In addition, an analytical model is developed to analyze the three-dimensional morphing structure easily. The shape memory dual-matrix composites are fabricated with woven fabrics based on the shape memory polymers, and an epoxy matrix is used to ensure a flexible and shape-recoverable structure. The shape recoverability of the shape memory polymer composite skins is verified by measuring the shape recovery ratio at various temperatures. Based on the tensile tests for the shape memory polymer composite skins and shape memory polymer hinges, it is found that the morphing structure can be highly flexible depending on temperature. Finally, the bending and shape recovery behaviors of the morphing structure are demonstrated.


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