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Strength statistics of adhesive contact between a fibrillar structure and a rough substrate

DSpace at IIT Bombay

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Title Strength statistics of adhesive contact between a fibrillar structure and a rough substrate
 
Creator PORWAL, PK
HUI, CY
 
Subject gecko foot-hair
enhanced adhesion
nanoscale
surface
interfaces
mechanics
design
force
fibrillar interfaces
adhesion strength statistics
random attachment strengths
random fibril lengths
surface roughness
size effects
 
Description Equal distribution of load among fibrils in contact with a substrate is an important characteristic of fibrillar structures used by many small animals and insects for contact and adhesion. This is in contrast with continuum systems where stress concentration dominates interfacial failure. In this work, we study how adhesion strength of a fibrillar system depends on substrate roughness and variability of the fibril structure, which are modelled using probability distributions for fibril length and fibril attachment strength. Monte Carlo simulations are carried out to determine the adhesion strength statistics where fibril length follows normal or uniform distribution and attachment strength has a power-law form. Our results indicate that the strength distribution is Gaussian ( normal) for both the uniform and the normal distributions for length. However, the fibrillar structure having normally distributed lengths has higher strength and lower toughness than one having uniformly distributed lengths. Our simulations also show that an increase in the compliance of the fibrils can compensate for both the substrate roughness and the attachment strength variation. We also show that, as the number of fibrils n increases, the load-carrying efficiency of each fibril goes down. For large n, this effect is found to be small. Furthermore, this effect is compensated by the fact that the standard deviation of the adhesive strength decreases as 1/root n.
 
Publisher ROYAL SOC
 
Date 2011-08-27T11:45:00Z
2011-12-26T12:57:54Z
2011-12-27T05:46:01Z
2011-08-27T11:45:00Z
2011-12-26T12:57:54Z
2011-12-27T05:46:01Z
2008
 
Type Article
 
Identifier JOURNAL OF THE ROYAL SOCIETY INTERFACE, 5(21), 441-448
1742-5689
http://dx.doi.org/10.1098/rsif.2007.1133
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11655
http://hdl.handle.net/10054/11655
 
Language en