scholarly journals Characterization of Sustainable Robotic Materials and Finite Element Analysis of Soft Actuators Under Biodegradation

2021 ◽  
Vol 8 ◽  
Author(s):  
Toshiaki Nagai ◽  
Ashitaka Kurita ◽  
Jun Shintake
Keyword(s):  
Mechanical Properties ◽  
Biodegradable Materials ◽  
Biodegradable Material ◽  
Element Analysis ◽  
Soft Actuator ◽  
Degradation Rates ◽  
Soft Actuators ◽  
And Control ◽  
Good Agreement

Biodegradability is an important property for soft robots that makes them environmentally friendly. Many biodegradable materials have natural origins, and creating robots using these materials ensures sustainability. Hence, researchers have fabricated biodegradable soft actuators of various materials. During microbial degradation, the mechanical properties of biodegradable materials change; these cause changes in the behaviors of the actuators depending on the progression of degradation, where the outputs do not always remain the same against identical inputs. Therefore, to achieve appropriate operation with biodegradable soft actuators and robots, it is necessary to reflect the changes in the material properties in their design and control. However, there is a lack of insight on how biodegradable actuators change their actuation characteristics and how to identify them. In this study, we build and validate a framework that clarifies changes in the mechanical properties of biodegradable materials; further, it allows prediction of the actuation characteristics of degraded soft actuators through simulations incorporating the properties of the materials as functions of the degradation rates. As a biodegradable material, we use a mixture of gelatin and glycerol, which is fabricated in the form of a pneumatic soft actuator. The experimental results show that the actuation performance of the physical actuator reduces with the progression of biodegradation. The experimental data and simulations are in good agreement (R2 value up to 0.997), thus illustrating the applicability of our framework for designing and controlling biodegradable soft actuators and robots.

scholarly journals Effect of Geometrical Shape on Axial Deformation of Soft Actuator

2021 ◽  
Vol 2115 (1) ◽  
pp. 012047
Author(s):  
Vishal Mehta ◽  
Mihir Chauhan
Keyword(s):  
Geometrical Shape ◽  
Light Weight ◽  
Lateral Deformation ◽  
Axial Deformation ◽  
Element Analysis ◽  
Lateral Direction ◽  
Soft Actuator ◽  
Angular Deflection ◽  
Soft Actuators ◽  
And Control

Abstract Soft actuators are the latest trend of research because of their light weight and ease of manufacturing and control. Soft actuators have expanded their fields and taken place in many applications where linear or angular deflection is required. Soft actuators are very useful in the applications where deflection is required with soft touch. Soft Actuators are highly compliant and adaptive to unknown environments. Because of these characteristics, soft actuators are very popular in the field of medical and in the applications where interaction with fragile structure is required. The soft actuators can give required responses mostly depends on their shape. Linear or angular deformation can be achieved by changing the geometrical shape of actuators. This paper presents the effect of geometrical shape on axial deformation of soft pneumatic actuator. Samples of soft actuators are selected with various shapes for finite element analysis. Results are obtained in form of axial and lateral deformation. An attempt is made to achieve good amount of axial deformation with very less or negligible lateral deformation by selecting appropriate shape. Based on the generated results, the shape is identified which gives desired results and more suitable among the selected nine samples. This sample can be useful in the application having space constraint in lateral direction.

scholarly journals Investigating of Mechanical Behavior of AA5083 in the Pressing Process Using Finite Element Analysis

2017 ◽  
Vol 11 (9) ◽  
pp. 51
Author(s):  
Babak Beglarzadeh ◽  
Behnam Davoodi
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Friction Stress ◽  
Forming Process ◽  
Element Analysis ◽  
Cold Forming ◽  
Aluminum Alloy 5083 ◽  
And Control

The process of cold forming is considered of the most different industries and the use of such process in the manufacture of components and small parts has expanded. Therefore, analyzing the behavior of metals in this process to identify and control durability that is the main factor of limiting process has particular importance in industrial forming processes. In this study, cold forming process of aluminum metal has been studied and its effect on its mechanical properties has been evaluated. For this purpose, first modeling piece of aluminum alloy 5083 for cold forming process is carried out and using finite element analysis, mechanical properties of considered piece during cold forming processes are investigated. The results show that by reducing friction, stress and strain during the process will reduce, thereby durability of the piece increases, or in other words, ductile fracture occurs in longer life and higher stresses. The results show that by proper forming operations, it can be improved the strength and durability of aluminum alloy. Finally, validation of results, by comparing simulation results with experimental results is carried out.

scholarly journals FDIR for the IMU Component of AOCS Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Maurício N. Pontuschka ◽  
Ijar M. da Fonseca
Keyword(s):  
Automatic Detection ◽  
Fault Identification ◽  
Space Applications ◽  
Tetrahedral Configuration ◽  
Orbit Control ◽  
Definition Of ◽  
And Control ◽  
Control Division ◽  
Good Agreement

The main objective of this paper is the study of a FDIR for an IMU aiming at space applications with focus on the gyro signal analysis and the tests of the filtering algorithms. The algorithms have been tested by using lab data provided by the DMC LABSIM (Physical’s Simulation Laboratory of the Space Mechanics and Control Division of INPE). The results have demonstrated good agreement with the concepts applied in this study. Automatic detection procedures are very important in the characterization of occurrence, definition of criteria, and device types in the scenario of AOCS FDIR. An IMU comprised of four gyros in a tetrahedral configuration is one of the assumed components for the AOCS (attitude and orbit control subsystem) considered in this work. The types of failures considered in this paper are the step abrupt change, ramp/drift/slow, stuck, cyclic, erratic, spike, and finally the stuck for variance alteration noise. An appropriate algorithm for the automatic detection of each type of fault is developed. The approach includes the mapping capability of fault event indicators to the IMU. This mapping is very important in the characterization of the occurrence, definition of criteria, and device types as well as associated fault identification for an AOCS.

Failure Stress Analysis of Adhesive T-Joint under Moisture Condition

2015 ◽  
Vol 786 ◽  
pp. 94-98
Author(s):  
S. Nurhashima ◽  
Mohd Afendi ◽  
Basirom Izzawati ◽  
A. Nor ◽  
Abdul Rahman Abdullah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Hot Water ◽  
Failure Stress ◽  
Element Analysis ◽  
Moisture Condition ◽  
Lightweight Structures ◽  
Test Compression ◽  
The Finite Element Analysis ◽  
Good Agreement

The use of adhesive structural in joining application offers the great demand due to its many advantages such as lightweight structures and flexible design. However, moisture provides significant problem and adverse effect on degrading the adhesive. The strength of the adhesive reduces because mechanical properties are known to reduce also with moisture environment. Therefore, this paper discusses about the adhesive T-joint test on specimen within moisture condition and specimen without moisture, at room temperature. Additionally, this study also analyses the failure stress when load is applied for both exposed conditions. Bulk specimens are compressed at room temperature, specimen without immersing in hot water, RT and specimen with immersing in three hot water conditions 80°C, 90°C, and 100°C at a constant time of 15 minutes. The adhesive of a 1.0mm thickness has been set for T-joint tensile test. Compression test revealed that mechanical properties of Young’s modulus decreased with the increase of water temperature. Experimental results indicated that the failure stress of adhesive T-joint at room temperature and 90°C was higher compared to that of specimen soaked in 80°C and 100°C of hot water. The behaviour of adhesive joint tests under static loading analysis of experiments and the finite element analysis using ANSYS 14.0 software have shown good agreement.

scholarly journals Effects of Flotage on Immersion Indentation Results of Bone Tissue: An Investigation by Finite Element Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Mingxing Zhou ◽  
Zunqiang Fan ◽  
Zhichao Ma ◽  
Yue Guo ◽  
Liguo Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Nanoindentation Test ◽  
Liquid Media ◽  
Depth Sensing ◽  
Element Analysis ◽  
Fea Simulation ◽  
The Difference

In reality, nanoindentation test is an efficient technique for probing the mechanical properties of biological tissue that soaked in the liquid media to keep the bioactivity. However, the effects of flotage imposed on the indenter will lead to inaccuracy when calculating mechanical properties (for instance, elastic modulus and hardness) by using depth-sensing nanoindentation. In this paper, the effects of flotage on the nanoindentation results of cortical bone were investigated by finite element analysis (FEA) simulation. Comparisons of nanoindentation simulation results of bone samples with and without being soaked in the liquid media were carried out. Conclusions show that the difference of load-displacement curves in the case of soaking sample and without soaking sample conditions varies widely based on the change of indentation depth. In other words, the nanoindentation measurements in liquid media will cause significant error in the calculated Young’s modules and hardness due to the flotage. By taking into account the effect of flotage, these errors are particularly important to the accurate biomechanics characterization of biological samples.

Design and Experiments of Pneumatic Soft Actuators

Robotica ◽  
2021 ◽  
pp. 1-10
Author(s):  
Liqiang Guo ◽  
Ke Li ◽  
Guanggui Cheng ◽  
Zhongqiang Zhang ◽  
Chu Xu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Production Line ◽  
Element Analysis ◽  
Soft Actuator ◽  
Flexible Material ◽  
The Future ◽  
Inner Diameter ◽  
Soft Actuators ◽  
Torsion Deformation

SUMMARY The soft actuator is made of superelastic material and embedded flexible material. In this paper, a kind of soft tube was designed and used to assemble two kinds of pneumatic soft actuators. The experiment and finite element analysis are used to comprehensively analyze and describe the bending, elongation, and torsion deformation of the soft actuator. The results show that the two soft actuators have the best actuation performance when the inner diameter of the soft tube is 4 mm. In addition, when the twisting pitch of the torsional actuator is 24 mm, its torsional performance is optimized. Finally, a device that can be used in the production line was assembled by utilizing those soft actuators, and some operation tasks were completed. This experiment provides some insights for the development of soft actuators with more complex motions in the future.

scholarly journals Trends in the Characterization of the Proximal Humerus in Biomechanical Studies: A Review

2020 ◽  
Vol 10 (18) ◽  
pp. 6514
Author(s):  
Angel D. Castro-Franco ◽  
Ismael Mendoza-Muñoz ◽  
Álvaro González-Ángeles ◽  
Samantha E. Cruz-Sotelo ◽  
Ana Maria Castañeda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Proximal Humerus ◽  
Three Dimensional ◽  
Bone Modeling ◽  
Element Analysis ◽  
Treatment Scenario ◽  
Time Requirements ◽  
Humerus Fractures ◽  
Mesh Properties

Proximal humerus fractures are becoming more common due to the aging of the population, and more related scientific research is also emerging. Biomechanical studies attempt to optimize treatments, taking into consideration the factors involved, to obtain the best possible treatment scenario. To achieve this, the use of finite element analysis (FEA) is necessary, to experiment with situations that are difficult to replicate, and which are sometimes unethical. Furthermore, low costs and time requirements make FEA the perfect choice for biomechanical studies. Part of the complete process of an FEA involves three-dimensional (3D) bone modeling, mechanical properties assignment, and meshing the bone model to be analyzed. Due to the lack of standardization for bone modeling, properties assignment, and the meshing processes, this article aims to review the most widely used techniques to model the proximal humerus bone, according to its anatomy, for FEA. This study also seeks to understand the knowledge and bias behind mechanical properties assignment for bone, and the similarities/differences in mesh properties used in previous FEA studies of the proximal humerus. The best ways to achieve these processes, according to the evidence, will be analyzed and discussed, seeking to obtain the most accurate results for FEA simulations.

Impact of the Chamber Shape on a Soft Actuator Mechanism to Mimic the Esophageal Swallowing Process

2018 ◽  
Author(s):  
Alberto Caballero-Ruiz ◽  
Juan A. Hernández-Angulo ◽  
Gabriel Ascanio Gasca ◽  
Leticia Vega-Alvarado ◽  
Leopoldo Ruiz-Huerta ◽  
...  
Keyword(s):  
Peristaltic Wave ◽  
Element Analysis ◽  
Soft Actuator ◽  
Integral Number ◽  
Physical Prototype ◽  
Human Esophagus ◽  
The One ◽  
Soft Actuators ◽  
Manufacturing Technologies ◽  
The Impact

A physical prototype of a human esophagus has been developed for reproducing the human swallowing process with the aim of studying various disorders that impair its function as well as for the development of new foods and technologies for their treatment. Several studies related to the peristalsis phenomena have been conducted in recent years by studying the effect of different parameters defining the peristaltic wave. Mathematical models have been developed to investigate the impact of an integral and a non-integral number of waves during the swallowing of food stuff such as jelly, tomato puree, among others. Swallowing through the esophagus has not only been studied numerically but also reported by using a pneumatic soft actuators. In the present work, the development of a soft actuator mechanism to reproduce the peristaltic wave as the one reported by F.J. Chen et. al. 2014 is described. Such a mechanism consists of a rubber structure that contains an array of chambers actuated by pressurized air to generate the peristaltic wave. The final chamber shape was determined after an iterative process, which involves the elastomer properties, different chamber shapes, finite element analysis and image processing. The characterization of the developed peristaltic mechanism was made by correlating a theoretical study of swallowing peristaltic model and the waveform obtained from the X-ray radiography analysis as the mechanism is actuated. As result, the soft actuator mechanism can reproduce a peristaltic waveform with a correlation coefficient near to 0.9 with respect to the mathematical model reported in literature. In addition, the manufacturing process based on additive manufacturing technologies is also presented.

Preliminary Characterization of Resilin Isolated from the Cockroach, Periplaneta Americana

1992 ◽  
Vol 292 ◽  
Author(s):  
Elizabeth Craig Lombardi ◽  
David L. Kaplan
Keyword(s):  
Mechanical Properties ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Periplaneta Americana ◽  
Insect Cuticle ◽  
Oligonucleotide Probes ◽  
Protein Matrix ◽  
Tryptic Fragment ◽  
Good Agreement

AbstractWe would like to mimic the mechanical properties of animal systems for the development of novel materials. Insect cuticle serves as one source of inspiration for the design of these materials. Cuticle is composed of chitin embedded in a protein matrix which may also contain plasticizers, fillers, crosslinkers, and minerals. The specific properties of the cuticle depend on the type, amount and interactions between each component. We are renewing the investigation of the elastic cuticle, resilin. Resilin, a protein-based elastomer first described in the early 1960s, has properties which have been reported to be most like those of ideal rubbers. We have examined resilin isolated from the prealar arms of the cockroach, Periplaneta americana. The results of amino acid analysis are in good agreement with earlier data reported for resilin. A series of tryptic fragments have been isolated and sequenced. These peptides have been used for the design of oligonucleotide probes for the identification of the gene(s) from a teneral cockroach cDNA library. A biopolymer, based on one tryptic fragment, has been designed and synthesized. We are continuing to treat resilin with residue specific proteases in order to map the resilin protein.

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