scholarly journals Design of Stretchable Electronics Against Impact

2016 ◽  
Vol 83 (10) ◽  
Author(s):  
J. H. Yuan ◽  
M. Pharr ◽  
X. Feng ◽  
John A. Rogers ◽  
Yonggang Huang
Keyword(s):  
Mechanical Properties ◽  
Viscoelastic Properties ◽  
Critical Thickness ◽  
Impact Resistance ◽  
Stretchable Electronics ◽  
Analytic Model ◽  
Device Failure ◽  
Low Modulus ◽  
Physical Impact ◽  
The Impact

Stretchable electronics offer soft, biocompatible mechanical properties; these same properties make them susceptible to device failure associated with physical impact. This paper studies designs for stretchable electronics that resist failure from impacts due to incorporation of a viscoelastic encapsulation layer. Results indicate that the impact resistance depends on the thickness and viscoelastic properties of the encapsulation layer, as well as the duration of impact. An analytic model for the critical thickness of the encapsulation layer is established. It is shown that a commercially available, low modulus silicone material offers viscous properties that make it a good candidate as the encapsulation layer for stretchable electronics.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Copper Foil ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Lightning Strike ◽  
Single Wall Carbon Nanotubes ◽  
Carbon Fibre Reinforced Polymer ◽  
The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

scholarly journals Evolution of the viscoelastic properties of painting stratigraphies: a moisture weathering and nanoindentation approach

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Mathilde Tiennot ◽  
Davide Iannuzzi ◽  
Erma Hermens
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Cultural Heritage ◽  
Mechanical Behaviour ◽  
Viscoelastic Properties ◽  
Viscoelastic Behaviour ◽  
Storage And Loss Moduli ◽  
Heritage Studies ◽  
Paint Films ◽  
The Impact

AbstractIn this investigation on the mechanical behaviour of paint films, we use a new ferrule-top nanoindentation protocol developed for cultural heritage studies to examine the impact of repeated relative humidity variations on the viscoelastic behaviour of paint films and their mechanical properties in different paint stratigraphies through the changes in their storage and loss moduli. We show that the moisture weathering impact on the micromechanics varies for each of these pigment-oil systems. Data from the nanoindentation protocol provide new insights into the evolution of the viscoelastic properties dsue to the impact of moisture weathering on paint films.

Phase Morphology, Thermal and Mechanical Properties of Compatibilized Nylon12/Natural Rubber Blends Using PS/MNR

2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Moisture Absorption ◽  
Rubber Particle ◽  
Impact Resistance ◽  
Phase Morphology ◽  
Thermal And Mechanical Properties ◽  
Binary Blend ◽  
Polyamide 12 ◽  
The Impact

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.

scholarly journals Effect of Three-dimensional Printing with Nanotubes on Impact Resistance

2019 ◽  
Author(s):  
Anne Schmitz
Keyword(s):  
Mechanical Properties ◽  
Lower Limb ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Impact Tester ◽  
The Impact ◽  
Dimensional Printing ◽  
Pendulum Impact ◽  
Pendulum Impact Tester

Abstract The types of biomedical devices that can be three-dimensional printed (3DP) is limited by the mechanical properties of the resulting materials. As a result, much research has focused on adding carbon nanotubes (CNT) to these photocurable polymers to make them stronger. However, there is little to no data on how CNTs affect the impact resistance of these polymers, an important property when designing and manufacturing lower limb prosthetics. The objective of this study was to expand the use of 3DP to prosthetics by testing the hypothesis that adding CNTs to a stereolithographic (SLA) photocurable resin will result in a cured polymer with increased impact resistance. Twenty-six total specimens: 13 with nanotubes and 13 without nanotubes, were printed on a Form2 SLA printer. Once all the specimens were printed, washed, and cured, the impact resistance was quantified using a pendulum impact tester in a notched Izod configuration. Contrary to the hypothesis, the specimens with SWCNTs (0.312 ± 0.036 ft*lb/in) had a significantly lower impact resistance compared to the non-SWCNT specimens (0.364 ± 0.055 ft*lb/in), U = 34.0, p = 0.004. This decreased impact resistance may be due to voids in the printed polymer around the aggregated nanotubes. Thus, SLA polymers still do not have the impact strength needed to be used for a full lower limb prosthetic.

Factorial Experimental Planning Applied for Evaluated Effect of Matrix Temperature and Screw Rotation Speed of Extrusion in Mechanical Properties and Dimensional Changes in PVC Pipes

2018 ◽  
Vol 930 ◽  
pp. 241-247
Author(s):  
J. Fiori Júnior ◽  
Raquel Piletti ◽  
J. Ilha ◽  
M. Pierini ◽  
Humberto Gracher Riella ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Significant Influence ◽  
Impact Resistance ◽  
Dimensional Change ◽  
Extrusion Process ◽  
Process Conditions ◽  
Dimensional Variation ◽  
Pvc Pipe ◽  
The Impact

This study evaluated the effects of temperature and speed screw rotation of rigid recycled PVC pipe extrusion process on mechanical properties and dimensional variation. In developing the experiments were used the factorial design method type 2k. Were studied the influence of process variables on the properties of impact resistance, dimensional change and tensile strength of PVC pipe. From this study, it was possible to define the best extrusion process conditions with a point of view on the best properties of PVC pipes. The results indicated that the screw rotation has a significant influence on the impact property. For the dimensional variation, the extrusion temperature had a significant influence. There is no significant statistical values for the tensile strength in the studied variables.

Influence of the Cellulose and Soft Wood Fibres on the Impact and Tensile Properties in Polypropylene Bio Composites

2021 ◽  
Vol 903 ◽  
pp. 134-139
Author(s):  
Jānis Zicans ◽  
Remo Merijs Meri ◽  
Tatjana Ivanova ◽  
Andrejs Kovalovs ◽  
Piotr Franciszczak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Resistance ◽  
Tensile Modulus ◽  
Response Surfaces ◽  
Design Parameters ◽  
Cellulose Fibres ◽  
Highest Weight ◽  
Weight Content ◽  
The Impact

Investigation presents an experimental study of mechanical properties of hybrid bio-composites made from man-made cellulose fibres and soft wood microfiller embedded into polypropylene homopolymer matrix at different weight contents. Mechanical properties such as elastic modulus, tensile strength, and impact resistance of the reinforced composites determined for various total weight contents of both biobased fillers were used as the design parameters. The problem was solved by planning the experiments and response surfaces method. The results demonstrate that using the both filler types enhance the mechanical properties. The tensile modulus increases by ~115%. The bio-composite with the highest weight content of man-made cellulose fibres and the lowest content of soft wood microfibers possesses maximum tensile strength (more 66 MPa). Addition of man-made cellulose fibres demonstrate a significant influence on the impact resistance of the investigated composites.

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