Nano-additive reinforcement of mixture epoxy syntactic foams

2019 ◽  
Vol 33 (12) ◽  
pp. 1674-1691 ◽  
Author(s):  
Kerrick R Dando ◽  
David R Salem
Keyword(s):  
Impact Analysis ◽  
Mechanical Response ◽  
Analysis Data ◽  
Halloysite Nanotubes ◽  
Peak Force ◽  
Syntactic Foams ◽  
Response Properties ◽  
Weight Percentage ◽  
Time To Peak ◽  
The Matrix

Carbon nanofibers (CNFs) and halloysite nanotubes (HNTs) were incorporated in syntactic foams containing a 90% by volume homogeneous mixture of (20/80 wt%) glass/thermoplastic microballoons to enhance the mechanical and impact response properties. Tensile, compressive, and impact tests were employed to comparatively characterize the effect of nano-additive reinforcement on mechanical response properties. Compressive strength and modulus enhancements as large as 39% and 18%, respectively, were achieved with a 0.125 wt% addition of CNF and increases of 61% and 7%, respectively, were achieved with a 0.125 wt% addition of HNT. Tensile strength and modulus enhancements as large as 107% and 68%, respectively, were achieved with a 0.125 wt% addition of CNF and increases of 104% and 70%, respectively, were achieved with a 0.125 wt% addition of HNT. Impact analysis data were used to show that measured peak force increased and build-up time to peak force decreased with increasing CNF or HNT weight percentage due to stiffening of the matrix. The smallest increase observed in peak force was 20% for a 0.125 wt% addition of CNF and 17% for a 0.125 wt% addition of HNT.

The rheological behaviour and thermal ageing characteristics of PP/MWCNT/glass fibre multiscale composites

2021 ◽  
pp. 096739112199290
Author(s):  
N Rasana ◽  
K Jayanarayanan ◽  
Krishna Prasad Rajan ◽  
Aravinthan Gopanna
Keyword(s):  
Hybrid Composites ◽  
Rheological Behaviour ◽  
Strain Energy Release ◽  
Critical Stress Intensity Factor ◽  
Thermal Ageing ◽  
Multiwalled Carbon ◽  
Weight Percentage ◽  
Fixed Weight ◽  
Multiscale Composite ◽  
The Matrix

Multiscale hybrid composites were prepared using varying weight percentages (0 to 5) of multiwalled carbon nanotubes (MWCNTs) as nanofiller and a fixed weight percentage (20) of short glass fibres as micro filler (in polypropylene (PP) matrix. The shear and extensional viscosity of the composites was measured using a capillary rheometer. It was observed that even at higher shear rates the synergism of micro and nanofillers in the matrix significantly enhanced the melt viscosity. The complex nanotube network entanglement with micro fillers and PP chains imparted restrictions to the polymer chain movements. The prepared samples were subjected to thermal ageing at 100°C for 4 days in hot air oven. After ageing, multiscale composite with 3 wt% MWCNTs exhibited 28.57% enhancement in strain at break, whereas the tensile strength and modulus reduced by 6.8% and 8% respectively. The fracture toughness properties like strain energy release rate and critical stress intensity factor were not affected for multiscale composite at the optimum content of 3 wt% MWCNT, even after thermal ageing.

scholarly journals Mechanical plasticity of collagen directs branch elongation in human mammary gland organoids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Buchmann ◽  
L. K. Engelbrecht ◽  
P. Fernandez ◽  
F. P. Hutterer ◽  
M. K. Raich ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Developmental Process ◽  
Branching Morphogenesis ◽  
Collagen Network ◽  
Mechanical Tension ◽  
Structural Reorganization ◽  
Linear Response Regime ◽  
Human Mammary Gland ◽  
The Matrix ◽  
Tension Generation

AbstractEpithelial branch elongation is a central developmental process during branching morphogenesis in diverse organs. This fundamental growth process into large arborized epithelial networks is accompanied by structural reorganization of the surrounding extracellular matrix (ECM), well beyond its mechanical linear response regime. Here, we report that epithelial ductal elongation within human mammary organoid branches relies on the non-linear and plastic mechanical response of the surrounding collagen. Specifically, we demonstrate that collective back-and-forth motion of cells within the branches generates tension that is strong enough to induce a plastic reorganization of the surrounding collagen network which results in the formation of mechanically stable collagen cages. Such matrix encasing in turn directs further tension generation, branch outgrowth and plastic deformation of the matrix. The identified mechanical tension equilibrium sets a framework to understand how mechanical cues can direct ductal branch elongation.

Fabrication of Bulk Functionally-Graded Syntactic Foams for Impact Energy Absorption

2012 ◽  
Vol 706-709 ◽  
pp. 711-716 ◽  
Author(s):  
Tadaharu Adachi ◽  
Masahiro Higuchi
Keyword(s):  
Theoretical Analysis ◽  
Energy Absorption ◽  
Functionally Graded ◽  
Fabrication Process ◽  
Syntactic Foams ◽  
Compression Tests ◽  
Matrix Resin ◽  
Local Fracture ◽  
Density Distributions ◽  
The Matrix

Function of functionally-graded (FG) foams as energy absorption material for impact was discussed on the basis of theoretical analysis, and fabrication process of the foams was proposed in the paper. The FG foams were found to be useful as impact absorber due to progressively local fracture or cushion in the theoretical analysis. Next the fabrication process of the FG foams was suggested. The graded dispersion of the micro-balloons was conducted before curing the matrix resin in the process. The density distributions in the FG foams were confirmed to be predicted by the numerical analysis on the basis of floating the micro-balloons. Finally, compression tests were carried out to evaluate mechanical properties.

Control of Rapidly Executed Forces to a Target

1987 ◽  
Vol 65 (3) ◽  
pp. 827-836
Author(s):  
Donald Siegel
Keyword(s):  
Visual Feedback ◽  
Predictor Variable ◽  
Peak Force ◽  
Important Predictor ◽  
Force Amplitude ◽  
Time Curve ◽  
Time To Peak ◽  
Hand Grip ◽  
Rapid Responses ◽  
Force Time

The purpose of the present study was to determine whether initial measures of impulse (i.e., area under the force-time curve) could be used to predict peak force (PF) in hand grip responses of 5- and 10-kg amplitude executed as rapidly as possible. 12 subjects performed 75 practice and 25 test contractions in each condition, with and without visual feedback. The time to peak (PT) for the 5-kg responses was 41 msec., while the 10-kg condition averaged 56 msec. Analyses demonstrated no effect for visual feedback. Correlational analyses of cumulative impulse sections from 5 msec., to PF within conditions showed that early measures of force within a response were not very good predictors of final force amplitude. Indeed, for both conditions upwards of 85% of a reponse needed to have occurred before 50% of PF variance could be predicted. Analyses across conditions demonstrated that 50% of PF variance could be predicted between 15 and 20 msec. PT was also an important predictor variable. By using PT along with cumulative impulse 50% of the variance in PF could be predicted prior to 10 msec., at 5 kg (25% of PT) and at about 15 msec., for 10 kg (27% of PT). Across conditions, 85% of the variance in PF was predictable by 5 msec. Such results suggest that either more refined response indices are needed in predicting response outcome or that even for very rapid responses some lower level “tuning” probably occurs after initiation.

Modeling the Matrix of Articular Cartilage Using a Continuous Fiber Angular Distribution Predicts Many Observed Phenomena

2009 ◽  
Author(s):  
Gerard A. Ateshian ◽  
Vikram Rajan ◽  
Nadeen O. Chahine ◽  
Clare Canal Guterl ◽  
Clark T. Hung
Keyword(s):  
Angular Distribution ◽  
Mechanical Response ◽  
Strain Curve ◽  
Collagen Matrix ◽  
Compressive Properties ◽  
Continuous Fiber ◽  
Stress Strain Curve ◽  
Theoretical Frameworks ◽  
The Matrix ◽  
Discrete Fiber

A number of theoretical frameworks embodying the disparity between tensile and compressive properties of cartilage have been proposed, accounting for the collagen fibers implicitly [1,2] or explicitly [3–5]. These models generally propose discrete fiber families to describe the collagen matrix. They are able to capture the most salient features of the cartilage mechanical response, namely, the tension-compression nonlinearity of the stress-strain curve [6].

Effect of Composition of Fibers on Properties of Hybrid Composites

2017 ◽  
Vol 7 (4) ◽  
pp. 28-43
Author(s):  
R. Panneer
Keyword(s):  
Glass Fiber ◽  
Hybrid Composites ◽  
Low Cost ◽  
Natural Fibers ◽  
Absorption Capacity ◽  
Weight Percentage ◽  
Specific Strength ◽  
The Matrix ◽  
Potential Applications ◽  
Weight Design

Fibers embedded in the matrix of another material are the best example of modern day composite materials. Hybrid Composites made out of an amalgamation of Natural Fibers such as banana, jute, and coir along with glass fiber embedded in polymers have potential applications in automotive, aircraft and marine industries for their unique characteristics like high specific strength, light weight, design flexibility, corrosion resistance, biodegradability and low cost. In this work, epoxy hybrid composites reinforced with glass fiber mats and banana, jute, coir fibers of random lengths between 10-25 mm are prepared by varying their compositions in terms of weight percentage. The composites are fabricated by hand lay-up process and cut into test specimens as per ASTM Standards. Their mechanical characteristics such as Tensile Strength, Flexural Strength, Impact Strength, Hardness, Density and Water Absorption Capacity are evaluated and analysed.

Microstructure characterization and evaluation of mechanical properties of stir rheocast AA2024/TiB2 composite

2019 ◽  
Vol 54 (7) ◽  
pp. 981-997
Author(s):  
Semegn Cheneke ◽  
D Benny Karunakar
Keyword(s):  
Mechanical Properties ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Globular Structure ◽  
Cast Sample ◽  
X Ray ◽  
Weight Percentage ◽  
The Matrix ◽  
Fractured Surface

In this research, microstructure and mechanical properties of stir rheocast AA2024/TiB2 metal matrix composite have been investigated. The working temperature was 640℃, which was the selected semisolid temperature that corresponds to 40% of the solid fraction. Two weight percentage, 4 wt%, and 6 wt% of the TiB2 reinforcements were added to the matrix. The field emission scanning electron microscope micrographs of the developed composites showed a uniform distribution of the particles in the case of the 2 wt% and 4 wt% of the reinforcements. However, the particles agglomerated as the weight percentages of the reinforcement increases to 6%. The optical microscope of the liquid cast sample showed the dendritic structure, whereas the rheocast samples showed a globular structure. The X-ray diffraction analysis confirmed the distribution of the reinforcements in the matrix and the formation of some intermetallic compounds. Mechanical properties significantly improved by the addition of the reinforcements in the matrix. An increase in tensile strength of 13.3%, 40%, 28%, and 5% was achieved for the unreinforced rheocast sample, 2 wt%, 4 wt%, and 6 wt% reinforced rheocast samples respectively, compared to the liquid cast sample. An increase in 20% of hardness was attained for the composite with 2 wt% TiB2 compared to the liquid cast sample. According to the fractography analysis, small dimples were observed on the fractured surface of the unreinforced rheocast sample, whereas small and large voids were dominant on the fractured surface of the 2 wt% composite, which shows the ductile fracture mode.

Sign in / Sign up

Export Citation Format

Share Document