scholarly journals Plant Movements as Concept Generators for the Development of Biomimetic Compliant Mechanisms

2020 ◽  
Vol 60 (4) ◽  
pp. 886-895 ◽  
Author(s):  
Simon Poppinga ◽  
David Correa ◽  
Bernd Bruchmann ◽  
Achim Menges ◽  
Thomas Speck

Synopsis Plant movements are of increasing interest for biomimetic approaches where hinge-free compliant mechanisms (flexible structures) for applications, for example, in architecture, soft robotics, and medicine are developed. In this article, we first concisely summarize the knowledge on plant movement principles and show how the different modes of actuation, that is, the driving forces of motion, can be used in biomimetic approaches for the development of motile technical systems. We then emphasize on current developments and breakthroughs in the field, that is, the technical implementation of plant movement principles through additive manufacturing, the development of structures capable of tracking movements (tropisms), and the development of structures that can perform multiple movement steps. Regarding the additive manufacturing section, we present original results on the successful transfer of several plant movement principles into 3D printed hygroscopic shape-changing structures (“4D printing”). The resulting systems include edge growth-driven actuation (as known from the petals of the lily flower), bending scale-like structures with functional bilayer setups (inspired from pinecones), modular aperture architectures (as can be similarly seen in moss peristomes), snap-through elastic instability actuation (as known from Venus flytrap snap-traps), and origami-like curved-folding kinematic amplification (inspired by the carnivorous waterwheel plant). Our novel biomimetic compliant mechanisms highlight the feasibility of modern printing techniques for designing and developing versatile tailored motion responses for technical applications. We then focus on persisting challenges in the field, that is, how to speed-boost intrinsically slow hydraulically actuated structures and how to achieve functional resilience and robustness, before we propose the establishment of a motion design catalog in the conclusion.

2021 ◽  
Vol 11 (16) ◽  
pp. 7336
Author(s):  
Shummaila Rasheed ◽  
Waqas Akbar Lughmani ◽  
Muhannad Ahmed Obeidi ◽  
Dermot Brabazon ◽  
Inam Ul Ahad

In this study, the printing capability of two different additive manufacturing (3D printing) techniques, namely PolyJet and micro-stereolithography (µSLA), are investigated regarding the fabrication of bone scaffolds. The 3D-printed scaffold structures are used as supports in replacing and repairing fractured bone tissue. Printed bone scaffolds with complex structures produced using additive manufacturing technology can mimic the mechanical properties of natural human bone, providing lightweight structures with modifiable porosity levels. In this study, 3D scaffold structures are designed with different combinations of architectural parameters. The dimensional accuracy, permeability, and mechanical properties of complex 3D-printed scaffold structures are analyzed to compare the advantages and drawbacks associated with the two techniques. The fluid flow rates through the 3D-printed scaffold structures are measured and Darcy’s law is applied to calculate the experimentally measured permeability. The Kozeny–Carman equation is applied for theoretical calculation of permeability. Compression tests were performed on the printed samples to observe the effects of the printing techniques on the mechanical properties of the 3D-printed scaffold structures. The effect of the printing direction on the mechanical properties of the 3D-printed scaffold structures is also analyzed. The scaffold structures printed with the µSLA printer demonstrate higher permeability and mechanical properties as compared to those printed using the PolyJet technique. It is demonstrated that both the µSLA and PolyJet printing techniques can be used to print 3D scaffold structures with controlled porosity levels, providing permeability in a similar range to human bone.


Author(s):  
Mohammad Abshirini ◽  
Mohammad Charara ◽  
Yingtao Liu ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan

This paper presents the additive manufacturing of electrically conductive polydimethylsiloxane (PDMS) nanocomposites for in-situ strain sensing applications. A straight line of pristine PDMS was first 3D printed on a thin PDMS substrate using an in-house modified 3D printer. Carbon nanotubes (CNTs) were uniformly sprayed on top of uncured PDMS lines. An additional layer of PDMS was then applied on top of CNTs to form a thin protective coating. The 3D printed PDMS/CNT nanocomposites were characterized using a scanning electron microscope (SEM) to validate the thickness, CNT distribution, and microstructural features of the sensor cross-section. The strain sensing capability of the nanocomposites was investigated under tensile cyclic loading at different strain rates and maximum strains. Sensing experiments indicate that under cyclic loading, the changes in piezo resistivity mimic, both, the changes in the applied load and the measured material strain with high fidelity. Due to the high flexibility of PDMS, the 3D printed sensors have potential applications in real-time load sensing and structural health monitoring of complex flexible structures.


2021 ◽  
Author(s):  
Aram Khosh Ettekal

The following report has been created to provide a broad range of information on current additive manufacturing technologies, their present applications in commercial and industrial sectors and predictions for their future deployment in those sectors. The report also examines the ongoing research and development of a variety of 3D printing techniques. The review is divided into three sections. The first section is composed of one to two page summaries of academic journals, thesis papers, consultant perspective articles and company releases. Each individual summary provides a synopsis of the article, as well as what the authors foresee as the future implications of the topic they explored. The second section contains summaries and reviews of technical studies on various aspects of several different 3D printing technologies. Lastly the third section introduces implementation strategy for 3D printed components and presents a study that highlights the effect of part orientation on the structural integrity of the printed components.


2021 ◽  
Author(s):  
Aram Khosh Ettekal

The following report has been created to provide a broad range of information on current additive manufacturing technologies, their present applications in commercial and industrial sectors and predictions for their future deployment in those sectors. The report also examines the ongoing research and development of a variety of 3D printing techniques. The review is divided into three sections. The first section is composed of one to two page summaries of academic journals, thesis papers, consultant perspective articles and company releases. Each individual summary provides a synopsis of the article, as well as what the authors foresee as the future implications of the topic they explored. The second section contains summaries and reviews of technical studies on various aspects of several different 3D printing technologies. Lastly the third section introduces implementation strategy for 3D printed components and presents a study that highlights the effect of part orientation on the structural integrity of the printed components.


2020 ◽  
Vol 110 (11-12) ◽  
pp. 752-757
Author(s):  
Lukas Weiser ◽  
Marco Batschkowski ◽  
Niclas Eschner ◽  
Benjamin Häfner ◽  
Ingo Neubauer ◽  
...  

Die additive Fertigung schafft neue Gestaltungsfreiheiten. Im Rahmen des Prototypenbaus und der Kleinserienproduktion kann das Verfahren des selektiven Laserschmelzens genutzt werden. Die Verwendung in der Serienproduktion ist bisher aufgrund unzureichender Bauteilqualität, langen Anlaufzeiten sowie mangelnder Automatisierung nicht im wirtschaftlichen Rahmen möglich. Das Projekt „ReAddi“ möchte eine erste prototypische Serienfertigung entwickeln, mit der additiv gefertigte Bauteile für die Automobilindustrie wirtschaftlich produziert werden können. Additive manufacturing (AM) offers new freedom of design. The selective laser-powderbed fusion (L-PBF) process can be used for prototyping and small series production. So far, it has not been economical to use it on a production scale due to insufficient component quality, long start-up times and a lack of automation. The project ReAddi aims to develop a first prototype series production to cost-effectively manufacture 3D-printed components for the automotive industry.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Liang Wu ◽  
Stephen Beirne ◽  
Joan-Marc Cabot Canyelles ◽  
Brett Paull ◽  
Gordon G. Wallace ◽  
...  

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...


2021 ◽  
Vol 5 (5) ◽  
pp. 119
Author(s):  
Stelios K. Georgantzinos ◽  
Georgios I. Giannopoulos ◽  
Panteleimon A. Bakalis

This paper aims to establish six-dimensional (6D) printing as a new branch of additive manufacturing investigating its benefits, advantages as well as possible limitations concerning the design and manufacturing of effective smart structures. The concept of 6D printing, to the authors’ best knowledge, is introduced for the first time. The new method combines the four-dimensional (4D) and five-dimensional (5D) printing techniques. This means that the printing process is going to use five degrees of freedom for creating the final object while the final produced material component will be a smart/intelligent one (i.e., will be capable of changing its shape or properties due to its interaction with an environmental stimulus). A 6D printed structure can be stronger and more effective than a corresponding 4D printed structure, can be manufactured using less material, can perform movements by being exposed to an external stimulus through an interaction mechanism, and it may learn how to reconfigure itself suitably, based on predictions via mathematical modeling and simulations.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 617
Author(s):  
Ruben Foresti ◽  
Benedetta Ghezzi ◽  
Matteo Vettori ◽  
Lorenzo Bergonzi ◽  
Silvia Attolino ◽  
...  

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.


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