Analysis of the biodynamic interaction between the fingertip and probe in the vibrotactile tests: The influences of the probe/fingertip contact orientation and static indentation

2009 ◽  
Vol 42 (2) ◽  
pp. 116-124 ◽  
Author(s):  
John Z. Wu ◽  
Kristine Krajnak ◽  
Daniel E. Welcome ◽  
Ren G. Dong
Author(s):  
MUDASSIR SYED ◽  
HUSSAIN MANZOOR .M ◽  
SHANKAR RAVI.D.V. ◽  
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2021 ◽  
pp. 109963622199387
Author(s):  
Mathilde Jean-St-Laurent ◽  
Marie-Laure Dano ◽  
Marie-Josée Potvin

The effect of extreme cold temperatures on the quasi-static indentation and the low velocity impact behavior of woven carbon/epoxy composite sandwich panels with Nomex honeycomb core was investigated. Impact tests were performed at room temperature, –70°C, and –150°C. Two sizes of hemispherical impactor were used combined to three different impactor masses. All the impact tests were performed at the same initial impact velocity. The effect of temperature on the impact behavior is investigated by studying the load history, load-displacement curves and transmitted energy as a function of time curves. Impact damage induced at various temperatures was studied using different non-destructive and destructive techniques. Globally, more damages are induced with impact temperature decreasing. The results also show that the effect of temperature on the impact behavior is function of the impactor size.


2004 ◽  
Vol 843 ◽  
Author(s):  
Adolfo Franco Júnior ◽  
Steve G. Roberts

ABSTRACTArrays of closely spaced quasi-static indentation were made on specimens of polycrystalline α-Al2O3, mean grain size G=1.2, 3.8 and 14.1 μm. The critical indentation spacing to produce crack coalescence between indentations, and thus significant loss of material from the surface, was determined. These data are compared to results for low-impact-velocity wet erosive wear on the same materials; a good correspondence is found. The indentation data can be used to produce “wear maps”, which provide a guideline for predicting the low-impact-velocity erosive wear resistance of brittle materials.


2014 ◽  
Vol 970 ◽  
pp. 317-319 ◽  
Author(s):  
Syed Mohd Saiful Azwan ◽  
Yahya Mohd Yazid ◽  
Ayob Amran ◽  
Behzad Abdi

Fibre reinforced polymer (FRP) plates subject to quasi-static indentation loading were studied. The plates were fabricated from three layers of chopped strand mat glass fibre and polyester resin using vacuum infusion process. Indentation tests were conducted on the plates with loading rates of 1 mm/min, 10 mm/min, 100 mm/min and 500 mm/min using a hemispherical tip indenter with diameter 12.5 mm. The plates were clamped in a square fixture with an unsupported space of 100 mm × 100 mm. The loads and deflections at the indented location were measured to give energy absorption-deflection curves. The results showed that the loading rate has a large effect on the indentation behaviour and energy absorbed.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
C. Suresh Kumar ◽  
K. Saravanakumar ◽  
P. Prathap ◽  
M. Prince ◽  
G. Bharathiraja ◽  
...  

The effect of reinforcement phases on indentation resistance and damage behavior of glass/epoxy laminates was investigated in this research work. Woven glass fiber mat and nonwoven chopped glass fiber mat were used as fiber reinforcement phases for fabricating the laminates. Low-velocity impact and quasi-static indentation tests were performed on both laminates to investigate the contact behavior and energy-absorbing capability. Moreover, the acoustic emission (AE) technique was employed to monitor the indentation damage resistance. AE parameters including normalized cumulative counts (NCC), normalized cumulative energy (NCE), rise angle (RA), and felicity ratio (FR) were analyzed. The bidirectional laminates showed premature load drops and drastic changes in the normalized cumulative counts/energy profile in the beginning of loading cycles, indicating the development of macrodamage such as debonding/delamination. AE sentry function results of bidirectional laminates show longer PII function at the earlier stages, associated with minor PIII function and greater PIV function, indicating the continuous degradation and progression of damage. In contrast, the chopped laminates exhibited superior postimpact performance than the bidirectional laminates. The presence of randomly oriented fibres prevents the delamination crack propagation during compression loading, which was attributed with the increased residual compressive strength.


2015 ◽  
Author(s):  
Timothy Briggs ◽  
Shawn Allen English ◽  
Stacy Michelle Nelson

Author(s):  
M. O. Neplevksy

The parameters of drilling boreholes (including depth, diameter, angle of borehole inclination, cross-section) that are currently used for the making bored piles under the conditions of dense urban area, have been considered. The review about modern technologies of drilling boreholes used for making bored piles has been prepared. The updated classification of drilling technologies used for the making bored piles, which taking into account the nature of the removal of the destroyed rock and the movement of the drilling tool, the type of drilling tool, as well as the method of mounting the borehole walls, has been proposed. The classification, according to the nature of removal of the destroyed rock, distinguishes technologies providing or not providing the removal of destroyed rock. According to the nature of movement of the drilling tool, the rotary, shock and vibration technologies, as well as a static indentation technology, can be identified. According to the type of drilling tools, the classification divides methods into hollow drill stem with sacrificial drill bit and soil compactor and displacement tools with a starter auger section, augers, drilling buckets, core barrels, belling buckets, roller, impact and three-way bits, grabs. According to the methods of well casing, the technologies can be divided into the ones, allowing and not allowing the casing of well.


2018 ◽  
Vol 7 (3.11) ◽  
pp. 193
Author(s):  
Ummu Raihanah Hashim ◽  
Aidah Jumahat ◽  
Muhammad Fashan Md Ghazali

Synthetic FRP have been used for many years in wide applications owing to their versatility and good performance. However, environmental problems caused by extensive use of polymeric materials arise mainly due to lack of landfill spaces and depletion of finite resources of fossil raw materials, such as petroleum or natural gas. Hence, materials derived from natural products are emerging as potential substitutes for petroleum-based material. The usage of natural fibre reinforced polymer (NFRP) composite have triggered considerable interest to explore the usefulness of this material. Excellent energy absorption of sandwich-structured composite made it a versatile structure used in various industries such transportation, automotive, building construction and marine. On top of that, the research data on aluminium foam as a core material in sandwich panel are limited and need to be further studied. This research is aimed to determine the quasi-static indentation properties of Basalt Fibre Reinforced Polymer/Aluminium Foam (BF-AF) sandwich panel and compare with the properties of Glass Fibre Reinforced Polymer/Aluminium Foam (GF-AF) sandwich panel. In this study, BFRP and GFRP composites with nanosilica were fabricated using vacuum bagging method. Aluminium foam was used as a core in the sandwich panel structure. The quasi-static indentation tests were performed using 10mm indenter and the specimen size was 50mm x 50mm with thickness of 3mm. The effect of aluminum foam on indentation properties were studied. The results showed that the addition of nanosilica enhanced the energy absorption, depth of penetration and damage area of the composites. The indentation properties of BF-AF were higher than those of GF-AF sandwich panel composites. Therefore, this research contributes to a new knowledge on the properties of aluminium foam-FRP composite materials


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