Nomenclature

xiii

NOMENCLATURE

n P

l o c a l c o n s t a n t , a (TI - v i s c o - e l a s t i c t r a n s f o r m a t i o n q u a n t i t y local constant l o c a l c o n s t a n t , c - p l a s t i c c o n t a c t f l o w stress c o n s t a n t diameter o f c o n t a c t area shear s t r a i n s p e c i f i c f r i c t i o n f o r c e , f - elementary t a n g e n t i a l force, fmol s p e c i f i c molecular foFce gravity h e i g h t of a s p e r i t i e s , t h i c k n e s s s p e c i f i c wear m a thema t i c a l o p e r a t o r Boltzmann c o n s t a n t , l o c a l c o n s t a n t s t r a i n hardening exponent, m a s s , s t r e n g t h e n i n g c o e f f i c i e n t , local c o n s t a n t number o f u n i t s o r s e g m e n t s , l o c a l c o n s t a n t p r e s s u r e , pr - r e a l c o n t a c t p r e s s u r e , pn nominal c o n t a c t p r e s s u r e , pm(olk - m o l e c u l a r a t t r a c t i o n stress t e m p e r a t u r e coe f i c i e n t o f U radius, relaxation rate, l o c a l constant s u r f a c e area o f one i r r e g u l a r i t y s h e a r stress, s t i m e , d u r a b i l i t y , t - mean bond l i f e t i m e d i s p l a c e m e n t , d e f o r m a t i o n , ua - d i s t a n c e o f a p p r o a c h v e l o c i t y , vp - v e l o c i t y o f c r a c k p r o p a g a t i o n , v C - a c t u a l r a t e of c r a c k g r o w t h width elevation o r height p i t c h o f a s p e r i t i e s , zw - p i t c h of wear bands ( w a v e l e n g t h ) , za local c o n s t a n t local constant local constant r e b o u n d number Young's modulus, E' s t o r a g e modulus, E" - loss modulus, El - u n r e l a x e d modulus, Em - r e l a x e d modulus, E elasticity, E* - e f f e c t i v e modulus force s h e a r modulus h a r d n e s s , HB - B r i n e 1 1 h a r d n e s s , H ' hardening c o e f f i c i e n t t h e r m a l power ( e n e r g y ) , B e s s e l f u n c t i o n wear i n t e n s i t y a c o e f f i c i e n t , K' stiffness molecule l e n g t h intermolecular i n t e r a c tion compressibility load d i s c h a r g e volume w e a r r e s i s t a n c e , s t r a i n gage r e s i s t a n c e c o n t a c t area r e a l c o n t a c t area a p p a r e n t c o n t a c t area

-

-

-

-

F

G

H I J K L N

0

P

Q

R S

'r 'n

-

-

-

x iv temperature a c t i v a t i o n energy specific wear volume of w e a r , V e n e r g y , work shear strength stress c o n c e n t r a t i o n coefficient f i r s t v i s c o - e l a s t i c loss p e a k , l o c a l c o n s t a n t s , a 0 of h e a t f l u x s e c o n d v i s c o - e l a s t i c loss p e a k , B,, 8, - c o e f f i c i e n t s of Bq' wear resistance t h i r d v i s c o - e l a s t i c loss peak local constant loss a n g l e , 6 ' h y s t e r e s i s loss c o e f f i c i e n t loss, A ' l o s s decrement normal s t r a i n bearing surface, relevant angle v i s c o s i t y , f o u r t h v i s c o - e l a s t i c loss peak c o n t a c t a n g l e , €Iz s u r f a c e t e n s i o n , €IvR - s u r f a c e f r e e e n e r g y a t t h e vapor-liquid i n t e r f a c e , etc. local c o n s t a n t thermal conductivity c o e f f i c i e n t interatomic distance, x jump d i s t a n c e , wave l e n g t h o f phonon. j P local constant coefficient of f r i c t i o n local c o n s t a n t , 2 - frequency angle density n o r m a l stress normal s t r e n g t h r e l a x a t i o n t i m e , p e r i o d , T~ Maxwell r e l a x a t i o n t i m e Sr/% scaling factor t i m e f a c t o r , frequency. elastic after e f f e c t , R rate o f e l a s t i c a f t e r e f f e c t Poisson's r a t i o , a coefficient function of

-

-

B

-

-

-

-

x -

-

..

-