Issue 77

Y. C. Arun et alii, Fracture and Structural Integrity, 77 (2026) 316-339; DOI: 10.3221/IGF-ESIS.77.19

changes in CoF. Filler content, on the other hand, consistently reduces friction under most circumstances, with 0.4–0.8 wt% CNFs encouraging sustained transfer film development. While SV and abrasive particle size show associated secondary effects, load and filler content generally dominate CoF reduction.

Figure 11: Interaction plots for coefficient of friction.

ANOVA for coefficient of friction The ANOVA results Tab. 9 show that load is the only statistically significant factor affecting CoF (F = 22.48, P = 0.008 < 0.05), indicating its primary participation in frictional behavior. On the other hand, strong P-values (> 0.05) for SV, AD, SiC particle size, and filler content indicate statistically insignificant individual impacts within the examined range. Filler has a larger contribution among these, but it is still not significant. The constructed model's adequacy is confirmed by the non-significant lack-of-fit (P = 0.733). Overall, load is the main factor influencing CoF; other factors either have a minor impact or do so through interaction effects.

Source Load (N) SV (m/s) AD (m)

DF

Adj SS 0.010778 0.000011 0.000016 0.000011 0.000911 0.003836 0.003524 0.000313

Adj MS 0.005389 0.000005 0.000008 0.000006 0.000455 0.000240 0.000235 0.000313

F-Value

P-Value

2 2 2 2 2

22.48 0.02 0.03 0.02 1.90

0.008 0.978 0.968 0.977 0.182

SiC Paper (μm) Filler (wt%)

Error

16 15

Lack-of-Fit Pure Error

0.75

0.733

1

Total

26 0.015731 Table 9: ANOVA results for main effect on coefficient of friction.

Regression equation and residual plots for coefficient of friction The regression Eqn. (5) establishes the quantitative relationship between CoF and the governing parameters, highlighting both the direction and relative influence of each factor. The negative coefficients for load (−0.004056), sliding velocity (−0.0045), abrading distance (−0.000018), and filler content (−0.00187) indicate a reduction in CoF with increasing parameter levels. Among these, sliding velocity and load exert the most pronounced influence, suggesting that higher contact severity facilitates stable tribolayer formation and reduces interfacial shear. The negative coefficient of filler confirms the lubricating role of CNFs through transfer film development.

m       s

( )

( )

( )

=

0.3635 0.004056 −

−

−

+

CoF µ

Load N

SV

AD m

0.0045

0.000018

(5)

( ) SiCPaper m µ

(

)

+

−

Filler wt

0.000042

0.00187

%

329