scholarly journals Soft Jumping Robot Using Soft Morphing and the Yield Point of Magnetic Force

2021 ◽  
Vol 11 (13) ◽  
pp. 5891
Author(s):  
Gang-Hyun Jeon ◽  
Yong-Jai Park
Keyword(s):  
Residual Stress ◽  
Polymer Materials ◽  
Rigid Base ◽  
Release Mechanism ◽  
Transfer Energy ◽  
Deformation Control ◽  
Energy Retention ◽  
Base Jumping ◽  
Jumping Robot ◽  
Soft Polymer

In this paper, soft-morphing, deformation control by fabric structures and soft-jumping mechanisms using magnetic yield points are studied. The durability and adaptability of existing rigid-base jumping mechanisms are improved by a soft-morphing process that employs the residual stress of a polymer. Although rigid body-based jumping mechanisms are used, they are driven by multiple components and complex structures. Therefore, they have drawbacks in terms of shock durability and fatigue accumulation. To improve these problems, soft-jumping mechanisms are designed using soft polymer materials and soft-morphing techniques with excellent shock resistance and environmental adaptability. To this end, a soft jumping mechanism is designed to store energy using the air pressure inside the structure, and the thickness of the polymer layer is adjusted based on the method applied for controlling the polymer freedom and residual stress deformation. The soft jumping mechanism can transfer energy more efficiently and stably using an energy storage and release mechanism and the rounded ankle structure designed using soft morphing. Therefore, the soft morphing and mechanisms of energy retention and release were applied to fabricate a soft robot prototype that can move in the desired direction and jump; the performance experiment was carried out.

scholarly journals High-Velocity Shear and Soft Friction at the Nanometer Scale

2021 ◽  
Vol 7 ◽  
Author(s):  
Per-Anders Thorén ◽  
Riccardo Borgani ◽  
Daniel Forchheimer ◽  
David B. Haviland
Keyword(s):  
High Speed ◽  
Surface Deformation ◽  
Soft Materials ◽  
Lateral Force ◽  
Velocity Shear ◽  
Polymer Materials ◽  
Amplitude Dependence ◽  
Dynamic Force ◽  
Stick Slip ◽  
Soft Polymer

We study high-speed friction on soft polymer materials by measuring the amplitude dependence of cyclic lateral forces on the atomic force microscope (AFM) tip as it slides on the surface with fixed contact force. The resulting dynamic force quadrature curves separate the elastic and viscous contributions to the lateral force, revealing a transition from stick-slip to free-sliding motion as the velocity increases. We explain force quadratures and describe how they are measured, and we show results for a variety of soft materials. The results differ substantially from the measurements on hard materials, showing hysteresis in the force quadrature curves that we attribute to the finite relaxation time of viscoelastic surface deformation.

The Effect of Specimen Size on the Determination of Residual Stress in Polymer Pipe Wall

2014 ◽  
Vol 627 ◽  
pp. 141-144 ◽  
Author(s):  
Jan Poduška ◽  
Jaroslav Kučera ◽  
Pavel Hutař ◽  
Martin Ševčík ◽  
J. Křivánek ◽  
...  
Keyword(s):  
Residual Stress ◽  
Axial Stress ◽  
Three Dimensional ◽  
Axial Direction ◽  
Polymer Materials ◽  
Axial Residual Stress ◽  
Axial Dimension ◽  
Measured Deformation ◽  
Different Dimensions

As a result of the production process, there are axial and tangential residual stresses present in pressure pipes made of polymer materials such as polyethylene or polypropylene. The residual stress magnitude and distribution have a significant influence on the pipe lifetime. In this contribution the results from experiments focused on determining the tangential residual stress distribution in the walls of polypropylene pipes of different dimensions are compared. The experimental method used involves measuring the deformation of ring shaped specimens that were slit in the axial direction. Measured deformation of the ring specimen is a result of the tangential and axial stress superposition. However, the effect of the axial residual stress depends on the specimen axial dimension and tangential residual stress estimated basing on experimental data should be corrected according to axial dimension of the specimen used. The correction suggested in this article is determined based on three-dimensional FEM simulations of the experiment.

PREPARATION, CHARACTERIZATION AND DRUG DELIVERY BEHAVIOR OF DEXAMETHASONE-LOADED OLIBANUM MICROSPHERE

2018 ◽  
Vol 30 (05) ◽  
pp. 1850031
Author(s):  
Parastoo Namdarian ◽  
Ali Zamanian ◽  
Azadeh Asefnejad ◽  
Maryam Saeidifar
Keyword(s):  
Tissue Engineering ◽  
Drug Carrier ◽  
Good Choice ◽  
Polymer Materials ◽  
Bioactive Molecules ◽  
Release Mechanism ◽  
Natural Polymers ◽  
Tissue Engineering Scaffolds ◽  
Active Research ◽  
Drug Carrier System

In recent years, the strategy of using microspheres as drug carrier system has been very much considered. Also the use of natural polymers for pharmaceutical applications is very attractive. Given that various polymer materials are available for making microspheres, there is an active research to develop new, safe and effective release for microspheres. Olibanum is used as a drug carrier in this study. Also dexamethasone (DEX) is one of the commonly bioactive molecules used in bone tissue engineering. In this research, the purification and characterization of olibanum were first studied by FTIR, XRD, pH determination and MTT test. Due to its non-toxicity, biocompatibility, availability and biodegradability, this material can be a good choice as a natural polymer. Then the microspheres were synthesized with single emulsion method and studied by SEM and FTIR. The morphology and structure of the microspheres revealed that they are spherical and separate, which have rough and porous surface. Also the release mechanism of drug from olibanum microspheres was determined in accordance with the different kinetic drug release models. Investigating the drugs release behavior and degradation rate of microspheres revealed that they were suitable for dexamethasone-controlled release and can be used well in tissue engineering scaffolds.

Quick and large electrostrictive deformation of non-ionic soft polymer materials

2003 ◽  
Author(s):  
Toshihiro Hirai ◽  
Md. Zulhash Uddin ◽  
Jianming Zheng ◽  
Masaki Yamaguchi ◽  
Shigeyuki Kobayashi ◽  
...  
Keyword(s):  
Polymer Materials ◽  
Soft Polymer

scholarly journals Inductive Heating Using a High-Magnetic-Field Pulse to Initiate Chemical Reactions to Generate Composite Materials

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 535 ◽  
Author(s):  
Cordelia Zimmerer ◽  
Catalina Mejia ◽  
Toni Utech ◽  
Kerstin Arnhold ◽  
Andreas Janke ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Chemical Reactions ◽  
Induction Heating ◽  
Polymer Materials ◽  
Heating Process ◽  
Inductive Heating ◽  
Magnetic Field Pulse ◽  
Transfer Energy ◽  
Scanning Calorimetry ◽  
Field Pulse

Induction heating is efficient, precise, cost-effective, and clean. The heating process is coupled to an electrically conducting material, usually a metal. As most polymers are dielectric and non-conducting, induction heating is not applicable. In order to transfer energy from an electromagnetic field into polymer induction structures, conducting materials or materials that absorb the radiation are required. This report gives a brief overview of induction heating processes used in polymer technology. In contrast to metals, most polymer materials are not affected by electromagnetic fields. However, an unwanted temperature rise of the polymer can occur when a radio frequency field is applied. The now available high-field magnetic sources provide a new platform for induction heating at very low frequencies, avoiding unwanted thermal effects within the material. Using polycarbonate and octadecylamine as an example, it is demonstrated that induction heating performed by a magnetic-field pulse with a maximum flux density of 59 T can be used to initiate chemical reactions. A 50 nm thick Ag loop, with a mean diameter of 7 mm, placed in the polymer-polymer interface acts as susceptor and a resistive heating element. The formation of urethane as a linker compound was examined by infrared spectroscopic imaging and differential scanning calorimetry.

PARASWIFT – A HYBRID CLIMBING AND BASE JUMPING ROBOT FOR ENTERTAINMENT

2011 ◽  
Author(s):  
L. GEISSMANN ◽  
M. DENUDER ◽  
D. KEUSCH ◽  
L. PFIRTER ◽  
D. RÖTHLISBERGER ◽  
...  
Keyword(s):  
Base Jumping ◽  
Jumping Robot

scholarly journals How accurately do mechanophores report on bond scission in soft polymer materials?

2021 ◽  
Author(s):  
Friso F. C. Dubach ◽  
Wouter G. Ellenbroek ◽  
Cornelis Storm
Keyword(s):  
Polymer Materials ◽  
Bond Scission ◽  
Soft Polymer

scholarly journals The effect of crude drugs on the angiogenic property and dynamic viscoelasticity of PEMA-based soft polymer materials

2017 ◽  
Vol 36 (6) ◽  
pp. 770-777
Author(s):  
Wei-Qi WANG ◽  
Guang HONG ◽  
Jian-Min HAN ◽  
Hiroshi MURATA ◽  
Keiichi SASAKI
Keyword(s):  
Polymer Materials ◽  
Dynamic Viscoelasticity ◽  
Crude Drugs ◽  
Soft Polymer

Deformation Control and Chatter Suppression in 5-Axis Milling of Thin-Walled Blade

2011 ◽  
Vol 188 ◽  
pp. 314-318
Author(s):  
Bao Hai Wu ◽  
Ming Luo ◽  
Ding Hua Zhang ◽  
X. Zhou
Keyword(s):  
Residual Stress ◽  
Deformation Control ◽  
Tool Paths ◽  
Machining Quality ◽  
Chatter Suppression ◽  
Machining Deformation ◽  
Thin Walled

This paper deals with deformation control and chatter suppression in the milling of thin-walled blade. The purpose is to generate tool paths that can control machining deformation and suppress chatter during milling. To achieve this object, symmetrical spiral milling approach is proposed to release residual stress on both sides of the blade in the same machining circle to control machining deformation. Besides, in order to suppress chatter during milling of thin-walled blade, nonuniform-allowance is left on both sides of the blade during machining, this can effectively increase the rigidity, thereby chatter cannot easily occur during machining. Machining experiments showed that the proposed approaches can dramatically improve the machining quality, decrease deformation and suppress chatter in the milling of thin-walled blade.

Effect of residual stress on indentation testing for polymer materials

2017 ◽  
Vol 2017 (0) ◽  
pp. J0410102
Author(s):  
Tomoki AKAHORI ◽  
Shugo FUSHIMI ◽  
Takumi NAGAKURA ◽  
Akio YONEZU
Keyword(s):  
Residual Stress ◽  
Polymer Materials ◽  
Indentation Testing
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