A programmable powerful and ultra-fast water-driven soft actuator inspired from mutable collagenous tissue of sea cucumber

2021 ◽  
Author(s):  
Andrew Choi ◽  
Hyeonseok Han ◽  
Dong Sung Kim
Keyword(s):  
Elastic Modulus ◽  
Sea Cucumber ◽  
Soft Actuator ◽  
Collagenous Tissue

Sea-cucumber evolve to bear mutable collagenous tissue (MCT) which enables the change of its elastic modulus by a factor of 10 within a few seconds by controlling the release amount...

Changes in collagenous tissue microstructures and distributions of cathepsin L in body wall of autolytic sea cucumber (Stichopus japonicus)

2016 ◽  
Vol 212 ◽  
pp. 341-348 ◽  
Author(s):  
Yu-Xin Liu ◽  
Da-Yong Zhou ◽  
Dong-Dong Ma ◽  
Yan-Fei Liu ◽  
Dong-Mei Li ◽  
...  
Keyword(s):  
Sea Cucumber ◽  
Body Wall ◽  
Cathepsin L ◽  
Stichopus Japonicus ◽  
Collagenous Tissue

Novel non-cellular adhesion and tissue grafting in the mutable collagenous tissue of the sea cucumber Parastichopus parvimensis

1998 ◽  
Vol 201 (21) ◽  
pp. 3003-3013 ◽  
Author(s):  
G. K. Szulgit ◽  
R. E. Shadwick
Keyword(s):  
Wound Healing ◽  
Sea Cucumber ◽  
Wound Closure ◽  
Cellular Adhesion ◽  
Shear Stresses ◽  
Short Term ◽  
Cellular Processes ◽  
Collagenous Tissue ◽  
External Pressures

Previous work on wound healing in holothurians (sea cucumbers) has been concerned with the relatively long-term cellular processes of wound closure and regeneration of new tissue. In this report, we characterize a short-term adhesion that is a very early step in holothurian wound healing. Dissected pieces of dermis from the sea cucumber Parastichopus parvimensis adhered to each other after only 2 h of contact, whether the cells in the tissues were intact or had been lysed. Lapshear tests showed that the breaking stresses of adhered tissues reached approximately 0.5 kPa after 24 h of contact. Furthermore, dermal allografts were incorporated into the live recipient individuals without any external pressures, sutures or artificial gels to keep them in place. Dislodging the grafts after 24 h of contact required shear stresses of approximately 14 kPa. It appears that the adhesive property of the dermis plays a key role in the initiation of this grafting.

scholarly journals Mechanical adaptability of sea cucumber Cuvierian tubules involves a mutable collagenous tissue

2017 ◽  
Vol 220 (11) ◽  
pp. 2108-2119 ◽  
Author(s):  
Mélanie Demeuldre ◽  
Elise Hennebert ◽  
Marie Bonneel ◽  
Birgit Lengerer ◽  
Séverine Van Dyck ◽  
...  
Keyword(s):  
Sea Cucumber ◽  
Collagenous Tissue

scholarly journals Interfibrillar stiffening of echinoderm mutable collagenous tissue demonstrated at the nanoscale

2016 ◽  
Vol 113 (42) ◽  
pp. E6362-E6371 ◽  
Author(s):  
Jingyi Mo ◽  
Sylvain F. Prévost ◽  
Liisa M. Blowes ◽  
Michaela Egertová ◽  
Nicholas J. Terrill ◽  
...  
Keyword(s):  
Tensile Testing ◽  
Sea Cucumber ◽  
Neural Control ◽  
Fibrillar Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Collagenous Tissue ◽  
Chemically Induced ◽  
Collagenous Tissues

The mutable collagenous tissue (MCT) of echinoderms (e.g., sea cucumbers and starfish) is a remarkable example of a biological material that has the unique attribute, among collagenous tissues, of being able to rapidly change its stiffness and extensibility under neural control. However, the mechanisms of MCT have not been characterized at the nanoscale. Using synchrotron small-angle X-ray diffraction to probe time-dependent changes in fibrillar structure during in situ tensile testing of sea cucumber dermis, we investigate the ultrastructural mechanics of MCT by measuring fibril strain at different chemically induced mechanical states. By measuring a variable interfibrillar stiffness (EIF), the mechanism of mutability at the nanoscale can be demonstrated directly. A model of stiffness modulation via enhanced fibrillar recruitment is developed to explain the biophysical mechanisms of MCT. Understanding the mechanisms of MCT quantitatively may have applications in development of new types of mechanically tunable biomaterials.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

Performance study of RTV-2 Silicone Rubber Material For Soft Actuator by Experimental and Numerical methods: The Effect of Inflation Pressure and Wall Thickness

2020 ◽  
Vol 17 (1) ◽  
pp. 7524-7532 ◽  
Author(s):  
Deepak D. ◽  
Nitesh Kumar ◽  
Shreyas P. Shetty ◽  
Saurabh Jain ◽  
Manoj Bhat
Keyword(s):  
Numerical Methods ◽  
Wall Thickness ◽  
Silicone Rubber ◽  
Inflation Pressure ◽  
Performance Study ◽  
Rubber Material ◽  
Soft Actuator ◽  
Alternative Materials ◽  
Load Carrying ◽  
Influential Parameters

The expensive nature of currently used materials in the soft robotic industry demands the consideration of alternative materials for fabrication. This work investigates the performance of RTV-2 grade silicone rubber for fabrication of a soft actuator. Initially, a cylindrical actuator is fabricated using this material and its performance is experimentally assessed for different pressures. Further, parametric variations of the effect of wall thickness and inflation pressure are studied by numerical methods. Results show that, both wall thickness and inflation pressure are influential parameters which affect the elongation behaviour of the actuator. Thin (1.5 mm) sectioned actuators produced 76.97% more elongation compared to thick sectioned, but the stress induced is 89.61 % higher. Whereas, the thick sectioned actuator (6 mm) showed a higher load transmitting capability. With change in wall thickness from 1.5 mm to 6 mm, the elongation is reduced by 76.97 %, 38.35 %, 21.05 % and 11.43 % at pressure 100 kPa, 75 kPa, 50 kPa and 25 kPa respectively. The induced stress is also found reduced by 89.61 %, 86.66 %, 84.46 % and 68.68 % at these pressures. The average load carrying capacity of the actuator is found to be directly proportional to its wall thickness and inflation pressure.

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

2020 ◽  
Vol 14 (4) ◽  
pp. 7396-7404
Author(s):  
Abdul Malek Abdul Wahab ◽  
Emiliano Rustighi ◽  
Zainudin A.
Keyword(s):  
Theoretical Model ◽  
Resonance Frequency ◽  
Dynamic Testing ◽  
Experimental Results ◽  
Percentage Error ◽  
Initial Tension ◽  
Average Percentage ◽  
Soft Actuator ◽  
Average Percentage Error ◽  
Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

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