Segmentations in fins enable large morphing amplitudes combined with high flexural stiffness for fish-inspired robotic materials

2021 ◽  
Vol 6 (57) ◽  
pp. eabf9710
Author(s):  
Florent Hannard ◽  
Mohammad Mirkhalaf ◽  
Abtin Ameri ◽  
Francois Barthelat
Keyword(s):  
Mechanical Testing ◽  
Soft Materials ◽  
Flexural Stiffness ◽  
Mechanical Modeling ◽  
Prominent Feature ◽  
Grasping Forces ◽  
3D Printed ◽  
Fish Fins ◽  
And Function ◽  
Continuous Material

Fish fins do not contain muscles, yet fish can change their shape with high precision and speed to produce large and complex hydrodynamic forces—a combination of high morphing efficiency and high flexural stiffness that is rare in modern morphing and robotic materials. These “flexo-morphing” capabilities are rare in modern morphing and robotic materials. The thin rays that stiffen the fins and transmit actuation include mineral segments, a prominent feature whose mechanics and function are not fully understood. Here, we use mechanical modeling and mechanical testing on 3D-printed ray models to show that the function of the segmentation is to provide combinations of high flexural stiffness and high morphing amplitude that are critical to the performance of the fins and would not be possible with rays made of a continuous material. Fish fin–inspired designs that combine very soft materials and very stiff segments can provide robotic materials with large morphing amplitudes and strong grasping forces.

Design and development of a novel 3D-printed non-metallic self-locking prosthetic arm for a forequarter amputation

2020 ◽  
pp. 030936462094829 ◽  
Author(s):  
Trevor Binedell ◽  
Eugene Meng ◽  
Karupppasamy Subburaj
Keyword(s):  
Computer Aided Design ◽  
Ease Of Use ◽  
Prosthetic Design ◽  
Forequarter Amputation ◽  
Digital Scanning ◽  
Survey Results ◽  
3D Printed ◽  
And Function ◽  
The Cost ◽  
Aided Design

Background: Upper limb, in particular forequarter amputations, require highly customised devices that are often expensive and underutilised. Objectives: The objective of this study was to design and develop a comfortable 3D-printed cosmetic forequarter prosthetic device, which was lightweight, cool to wear, had an elbow that could lock, matched the appearance of the contralateral arm and was completely free of metal for a specific user’s needs. Study Design: Device design. Technique: An iterative user-centred design approach was used for digitising, designing and developing a functional 3D-printed prosthetic arm for an acquired forequarter amputation, while optimising the fit and function after each prototype. Results: The cost of the final arm was 20% less expensive than a traditionally-made forequarter prostheses in Singapore. The Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) 2.0 survey was administered, with results indicating that the 3D-printed arm was preferred due to its overall effectiveness, accurate size, ease of use and suspension. However, durability had a lower score, and the weight of the arm was 100 g heavier than the user’s current prosthesis. The technique described resulted in a precise fitting and shaped forequarter prosthesis for the user. Using the user’s feedback in the iterations of the design resulted in improved QUEST survey results indicating the device was effective, easy to use, perceived as lighter and more secure than the user’s traditionally-made device. Conclusion: A fully customised cosmetic forequarter prosthesis was designed and developed using digital scanning, computer-aided design modelling and 3D printing for a specific user. These technologies enable new avenues for highly complex prosthetic design innovations.

Structure, Process, and Material Influences for 3D Printed Lattices Designed With Mixed Unit Cells

2020 ◽  
Author(s):  
Gabriel Briguiet ◽  
Paul F. Egan
Keyword(s):  
Elastic Modulus ◽  
Mechanical Testing ◽  
Mechanical Response ◽  
Cell Types ◽  
Unit Cell ◽  
Ultraviolet Curing ◽  
Mechanical Responses ◽  
Lattice Design ◽  
Unit Cells ◽  
3D Printed

Abstract Emerging 3D printing technologies are enabling the design and fabrication of novel architected structures with advantageous mechanical responses. Designing complex structures, such as lattices, with a targeted response is challenging because build materials, fabrication process, and topological design have unique influences on the structure’s mechanical response. Changing any factor may have unanticipated consequences, even for simpler lattice structures. Here, we conduct mechanical compression experiments to investigate varied lattice design, fabrication, and material combinations using stereolithography printing with a biocompatible polymer. Mechanical testing demonstrates that a higher ultraviolet curing time increases elastic modulus. Material testing demonstrated that anisotropy does not strongly influence lattice mechanics. Designs were altered by comparing homogenous lattices of single unit cell types and heterogeneous lattices that combine two types of unit cells. Unit cells for heterogeneous structures include a Cube design for a high elastic modulus and Cross design for improved shear response. Mechanical testing of three heterogeneous layouts demonstrated how unit cell organization influences mechanical outcomes, therefore enabling the tuning of an elastic modulus that surpasses the law of averages designed for application-dependent mechanical needs. These findings provide a foundation for linking design, process, and material for engineering 3D printed structures with preferred properties, while also facilitating new directions in design automation and optimization.

Design of a Deformable Smart Tire Using Soft Actuator

2019 ◽  
Author(s):  
Vidya K. Nandikolla ◽  
Michael Costa ◽  
Nathan Boyd ◽  
Gilberto Rosales
Keyword(s):  
Force Feedback ◽  
Design Procedure ◽  
Nickel Titanium ◽  
Operating Conditions ◽  
Mechanical Modeling ◽  
Soft Actuator ◽  
Voltage Signal ◽  
3D Printed ◽  
Primary Focus ◽  
Soft Actuators

Abstract The unique functional properties of nickel-titanium Shape Memory Alloys (SMA) enable them to be used as actuators. This research paper demonstrates theoretically and experimentally the feasibility of using SMA in smart tires for a mobile robot. The design procedure for SMA as a coil spring actuator for a soft deformable wheel is described. The primary focus is the mechanical modeling, manufacturing, and system dynamics of a soft deformable wheel. The 3D printed soft tire exploits the capabilities of the SMA actuation using a voltage signal. The printed components are activated and integrated with electromechanical circuit for wireless communication system. The performance of the force feedback control system is evaluated at different operating conditions to demonstrate the shape-changing characteristic of the smart tire. The developed prototype is designed to propel forward and backward on flat and uneven surface. The experimental results obtained demonstrate the potential of SMA as soft actuators, its benefits and limitations as flexible systems.

scholarly journals Bionic forceps for the handling of sensitive tissue

2016 ◽  
Vol 2 (1) ◽  
pp. 91-93 ◽  
Author(s):  
Lucia Kölle ◽  
Oliver Schwarz
Keyword(s):  
Functional Models ◽  
Fin Ray ◽  
3D Printed ◽  
Fish Fins

AbstractAnatomical forceps are used for the handling of sensitive structures in medicine. Structures which are manipulated with these forceps can get damaged or slip out of the grip of the forceps. This paper presents a forceps using the bionic Fin-Ray-Effect inspired by fish-fins in order to handle vulnerable structures in particular. During the process of development, functional models of this forceps were designed, 3D-printed and evaluated.

Comparisons of Bending Stiffness of 3D Printed Samples of Different Materials

2016 ◽  
Author(s):  
Mahbub Ahmed ◽  
Md. R. Islam ◽  
Justin Vanhoose ◽  
Lionel Hewavitharana ◽  
Aaron Stanich ◽  
...  
Keyword(s):  
Bending Stiffness ◽  
Bending Test ◽  
Testing System ◽  
Materials Testing ◽  
Flexural Stiffness ◽  
Result Section ◽  
Bending Tests ◽  
System A ◽  
3D Printers ◽  
3D Printed

3D printing technology has become more affordable than ever before. Today 3D printers are not only used for making prototypes but are also being used to make good quality 3D parts for different purposes. A wide variety of filament materials are used in the market. Finding bending stiffness of different plastic filaments is the particular interest in the current study. The purpose of the project is to investigate the bending stiffness of different 3D printed beam samples. A series of samples for performing bending tests were designed using a solid modeling tool. These samples were printed with four different plastic filaments on a 3D printer in the engineering Lab of Southern Arkansas University. The samples were tested for flexural stiffness (bending) using a materials testing system. A popular 3-point bending test was conducted for this purpose. The force vs. deflection data was obtained to obtain the flexural stiffness of the beam samples. The results were discussed in detail in the result section of this paper.

Design Principles and Function of Mechanical Fasteners in Nature and Technology

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Lindsie Jeffries ◽  
David Lentink
Keyword(s):  
Research And Development ◽  
Mechanical Testing ◽  
Design Principles ◽  
Design Considerations ◽  
Loop Design ◽  
Mechanical Fasteners ◽  
The Creation ◽  
And Function ◽  
Novel Products

Abstract Probabilistic mechanical fasteners are used to provide secure, reversible, and repeatable attachments in both nature and industry. Since the first observation of this mechanism in nature, which led to the creation of hook-and-loop fasteners, there has been a multitude of variations on the basic hook-and-loop design. However, few fastener designs have looked back to nature for inspiration in creating novel products or improving existing fasteners. Given the diverse probabilistic mechanical fasteners employed in nature, there is opportunity to further the research and development of these underdeveloped fasteners. To this end, we present a framework which describes the theory, design considerations, modelling, and mechanical testing required to study probabilistic mechanical fasteners. We further provide a comparison of the performance of existing probabilistic mechanical fasteners found in nature and industry as a reference for novel bio-inspired designs. Finally, we discuss current areas of application and future opportunities for fastener innovation.

A novel 3D-printed centrifugal ultrafiltration method reveals in vivo glycation of human serum albumin decreases its binding affinity for zinc

Metallomics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1036-1043 ◽  
Author(s):  
Monica J. Jacobs ◽  
Cody W. Pinger ◽  
Andre D. Castiaux ◽  
Konnor J. Maloney ◽  
Dana M. Spence
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
High Glucose ◽  
Plasma Proteins ◽  
Structure And Function ◽  
3D Printed ◽  
And Function ◽  
Centrifugal Ultrafiltration

Plasma proteins are covalently modified in vivo by the high-glucose conditions in the bloodstreams of people with diabetes, resulting in changes to both structure and function.

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