Design and Analysis of a Programmable Rotational Element Utilizing Coupled Kresling Origami Modules

2020 ◽  
Author(s):  
Zhen Li ◽  
Narayanan Kidambi ◽  
Liangmo Wang ◽  
Kon-Well Wang
Keyword(s):  
Mechanical Properties ◽  
Modular Design ◽  
Design Guidelines ◽  
Rotational Stability ◽  
Height Ratio ◽  
Mechanical Responses ◽  
Design Flexibility ◽  
Rotational Element ◽  
Rotational Components ◽  
Selection Of

Abstract Origami–inspired designs are being explored extensively for structural and material applications in a variety of different engineering fields because of their attractive kinematic and mechanical properties, design flexibility, and multi-functionality. However, most if not all of these studies have focused on translational motions. Utilizing origami in replacing or enhancing torsional components, such as joints, shafts and motors, has received little attention. With this in mind, this research introduces an origami-inspired rotational element via a coupled Kresling modular design (CKMD). Two Kresling origami modules with opposite chirality are integrated, achieving pure rotational motion between two ends of polygon surfaces. A model with nondimensionalized parameters is developed and a key design variable (natural height ratio) is varied to investigate the kinematic and mechanical properties of CKMD. Results show that these properties can be tailored by strategic selection of the natural height ratio, which alters the energy landscapes of both Kresling modules and leads to qualitatively distinct mechanical responses. Further investigation shows that the rotational stability characteristics of CKMD — monostability, symmetric and asymmetric bistability — may be programmed in a similar manner. Design guidelines are discussed, and the outcomes lay the foundation for integrating programmable, origami-inspired, rotational components in mechanical systems.

Elaboration and Characterization of the Properties of Refractory Cr Base Alloys

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Molten Glass ◽  
Energy Production ◽  
Creep Properties ◽  
Refractory Alloys ◽  
Industrial Use ◽  
Kinetics Of ◽  
Selection Of

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.

scholarly journals Advances in Fabricating the Electrospun Biopolymer-Based Biomaterials

2021 ◽  
Vol 12 (2) ◽  
pp. 26
Author(s):  
Sebastian Wilk ◽  
Aleksandra Benko
Keyword(s):  
Mechanical Properties ◽  
Whey Protein ◽  
Antimicrobial Properties ◽  
Protein Isolate ◽  
Review Article ◽  
Animal Tissues ◽  
Green Material ◽  
Good Potential ◽  
Fibrous Morphology ◽  
Selection Of

Biopolymers formed into a fibrous morphology through electrospinning are of increasing interest in the field of biomedicine due to their intrinsic biocompatibility and biodegradability and their ability to be biomimetic to various fibrous structures present in animal tissues. However, their mechanical properties are often unsatisfactory and their processing may be troublesome. Thus, extensive research interest is focused on improving these qualities. This review article presents the selection of the recent advances in techniques aimed to improve the electrospinnability of various biopolymers (polysaccharides, polynucleotides, peptides, and phospholipids). The electrospinning of single materials, and the variety of co-polymers, with and without additives, is covered. Additionally, various crosslinking strategies are presented. Examples of cytocompatibility, biocompatibility, and antimicrobial properties are analyzed. Special attention is given to whey protein isolate as an example of a novel, promising, green material with good potential in the field of biomedicine. This review ends with a brief summary and outlook for the biomedical applicability of electrospinnable biopolymers.

scholarly journals Mechanical properties of dental restorative materials: relative contribution of laboratory tests

2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Clinical Performance ◽  
Dental Materials ◽  
Correct Selection ◽  
Relative Contribution ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Dental Restorative ◽  
Selection Of

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.

scholarly journals The impact of the health condition of oaks from the Krotoszyn Plateau on the mechanical properties of timber structures

2015 ◽  
Vol 57 (4) ◽  
pp. 224-232
Author(s):  
Jarosław Siwiński ◽  
Katarzyna Kubiak ◽  
Miłosz Tkaczyk ◽  
Anna Mazur ◽  
Ryszard Rekucki
Keyword(s):  
Mechanical Properties ◽  
Health Condition ◽  
Health State ◽  
Timber Structures ◽  
Strength Parameters ◽  
Modified Method ◽  
Strength Tests ◽  
Prior Selection ◽  
The Impact ◽  
Selection Of

Abstract The study was conducted to perform a comparative analysis of the mechanical properties of wood samples derived from oaks in the Krotoszyn Plateau, which depend on the health state of the trees. Strength parameters of oak wood were calculated for selected diseased and healthy trees (according to the Roloff classification). The study was conducted by a modified method described in the standard Polish Norm PN EN 408+ A1: 2012. For testing, prior selection of wood samples showed that more wood samples of diseased trees compared with those of healthy oaks did not fulfil the Polish standard requirements. According to the method used, the average results of strength tests of timber structures from healthy oaks exhibited higher strength parameters than those of the diseased trees.

scholarly journals Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

2016 ◽  
Vol 61 (1) ◽  
pp. 353-360 ◽  
Author(s):  
B. Dybowski ◽  
J. Szymszal ◽  
Ł. Poloczek ◽  
A. Kiełbus
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Chemical Composition ◽  
Aluminium Alloys ◽  
Mg Alloys ◽  
High Electrical Conductivity ◽  
Transportation Industry ◽  
Proper Selection ◽  
Ti Addition ◽  
Selection Of

Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the influence of alloys chemical composition on their properties. It has been revealed that Si and Ti addition decreases electrical conductivity of the Al-Si-Mg alloys, while Na addition increases it. The mechanical properties of the investigated alloys are decreased by both silicon and iron presence. Sodium addition increases ductility of the Al-Si-Mg alloys.

General Method for Optimizing Composite Patch Repairs

2015 ◽  
Vol 1120-1121 ◽  
pp. 670-674
Author(s):  
Abdelmadjid Ait Yala ◽  
Abderrahmanne Akkouche
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Optimization Problem ◽  
Composite Patch ◽  
Matlab Program ◽  
Patch Repairs ◽  
Selection Of ◽  
General Method

The aim of this work is to define a general method for the optimization of composite patch repairing. Fracture mechanics theory shows that the stress intensity factor tends towards an asymptotic limit K∞.This limit is given by Rose’s formula and is a function of the thicknesses and mechanical properties of the cracked plate, the composite patch and the adhesive. The proposed approach consists in considering this limit as an objective function that needs to be minimized. In deed lowering this asymptote will reduce the values of the stress intensity factor hence optimize the repair. However to be effective this robust design must satisfy the stiffness ratio criteria. The resolution of this double objective optimization problem with Matlab program allowed us determine the appropriate geometric and mechanical properties that allow the optimum design; that is the selection of the adhesive, the patch and their respective thicknesses.

scholarly journals Formation of microstructure and properties of Cu-3Ti alloy in thermal and thermomechanical processes

2017 ◽  
Vol 62 (1) ◽  
pp. 223-230 ◽  
Author(s):  
A. Szkliniarz
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Plastic Deformation ◽  
Cold Working ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Cold Plastic Deformation ◽  
Working Solution ◽  
Thermomechanical Processes ◽  
Selection Of

Abstract This paper presents the possibilities of forming the microstructure as well as mechanical properties and electrical conductivity of Cu-3Ti alloy (wt.%) in thermal and thermomechanical processes that are a combination of homogenising treatment, hot and cold working, solution treatment and ageing. Phase composition of the alloy following various stages of processing it into the specified semi-finished product was being determined too. It was demonstrated that the application of cold plastic deformation between solution treatment and ageing could significantly enhance the effect of hardening of the Cu-3Ti alloy without deteriorating its electrical conductivity. It was found that for the investigated alloy the selection of appropriate conditions for homogenising treatment, hot and cold deformation as well as solution treatment and ageing enables to obtain the properties comparable to those of beryllium bronzes.

A statistical analysis of low-stress mechanical properties of warp-knitted fabrics

2016 ◽  
Vol 88 (4) ◽  
pp. 467-479 ◽  
Author(s):  
Ka-yan Yim ◽  
Chi-wai Kan
Keyword(s):  
Mechanical Properties ◽  
Evaluation System ◽  
Natural Fibers ◽  
Physical Parameters ◽  
Knitted Fabrics ◽  
Fabric Hand ◽  
Low Stress Mechanical Properties ◽  
Fabric Weight ◽  
Fabric Structures ◽  
Selection Of

Fabric hand is an indispensable characteristic for the selection of fabric and product development and the buying consideration for manufacturers and consumers. However, there is little comprehensive work on the hand feel property of warp-knitted fabrics due to the mainstream natural fibers (cotton, wool and silk) and other fabric structures (woven, weft-knitted and nonwoven). The increasing potential for the wide variety of applications and development of warp-knitted fabrics is not only because its fabric hand gives better determination for fabric marketing, but also because it provides extensive scope for fabric performance and appearance. This paper reports an experimental study on the integrated fabric hand behavior of a series of warp-knitted fabrics made for various apparel applications, such as sportswear, lingerie and leisure wear. These 105 fabrics were produced by varying different physical parameters, including fabric weight and fabric thickness. The Kawabata Evaluation System for Fabric (KES-F) was employed to obtain the fabric hand properties (primary hand value and total hand value) related with stiffness, smoothness and softness. All low-stress mechanical properties and fabric hand values from the testing results were used to verify the applicability of the KES-F on warp-knitted fabrics and to analyze the relationships of fabric parameters and hand characteristics. The results indicate that the KES-F is an appropriate tool to measure the hand attributes of warp-knitted samples, and moderate correlations between physical properties and mechanical behavior were found.

Electrical and Mechanical Properties of the Red and White Muscles in the Silver Carp

1972 ◽  
Vol 57 (2) ◽  
pp. 551-567
Author(s):  
T. YAMAMOTO
Keyword(s):  
Mechanical Properties ◽  
White Muscle ◽  
Silver Carp ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Resting Membrane Potential ◽  
Mechanical Responses ◽  
Red Muscle ◽  
Red And White Muscles ◽  
Specific Membrane

1. Electrical and mechanical properties of the red muscle (M. levator pinnae pectoralis) and white muscle (M. levator pinnae lateralis abdominis) in the silver carp (Carassius auratus Linné) were investigated by using caffeine and thymol. 2. A complete tetanus could be produced in the red muscle. But in the white muscle no tetanus was produced and there was a gradual decrease in tension during continuous stimulation, even at a frequency of 1 c/s or less. 3. Caffeine (0.5-1 mM) and thymol (0.25-0.5 mM) potentiated the twitch tension in both muscles without an increase in the resting tension; they produced a contracture in both muscles when the concentration was increased further. 4. The falling phase of the active state of contraction was nearly the same in both muscles and was prolonged by caffeine (0.5 mmM) and by thymol (0.25 mM). 5. The resting membrane potential of the red muscle was scarcely affected by caffeine (0.5-5 mM), whereas in the white muscles a depolarization of 10 mV was observed with caffeine of more than 2 mM. The resting potential of both muscles was little changed by o.25 mm thymol. However, at a concentration of more than 0.5mM thymol depolarized the membrane in both muscles to the same extent. 6. In caffeine (2-3 mM) solution the mean specific membrane resistance was reduced from 8.8 kΩ cm2 to 6.0 kΩ cm2 in the red muscle, and from 5.0 kΩ cm2 to 2.7 kΩ cm2 in the white muscle. In thymol (0.5-1 mM) solution it was reduced from 11.2 kΩcm2 to 6.5 kΩ cm2 in the red muscle, and from 5.4kΩ cm2 to 3.1 kΩ) cm2 in the white muscle. The specific membrane capacitance, calculated from the time constant and the membrane resistance, remained more or less the same in both muscles after a treatment with these agents. 7. Electrical properties of the muscles and the effects of caffeine and thymol on mechanical responses suggest that there are no fundamental differences between red and white muscles except for the excitation-contraction coupling. A lack of summation of twitch, a successive decline of twitch, and inability to produce potassium contracture in the white muscle may be due to the fact that the Ca-releasing mechanism is easily inactivated by depolarization of the membrane.

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