TY - JOUR
T1 - A study of size effects and length scales in fracture and fatigue of metals by second gradient modelling
AU - Stamoulis, K.
AU - Giannakopoulos, A. E.
PY - 2012/9/1
Y1 - 2012/9/1
N2 - As the dimensions of structures are scaled down to the micro- and nano-domains, the mechanical behaviour becomes size dependent and thus, we cannot expect the classical elasticity solutions to hold. In particular, recent experimental investigations of fatigue strength of metals show pronounced strengthening due to the influences of small geometrical dimensions. Based on second gradient elasticity framework as particularized on beams, closed form solutions to idealized problems of elastic cantilever bending, elastic three-point bending and elasto-plastic torsion have been found, showing considerable stiffening, toughening and hardening, respectively, compared to the classical theory predictions. In these models, the intrinsic material length scale was taken to be constant. Furthermore, we describe a gradient solid with a characteristic length which is not a fixed material parameter but depends on the amount of plastic effective strain amplitude, as obtained from cyclic strain hardening. A respective evolution law is suggested and discussed.
AB - As the dimensions of structures are scaled down to the micro- and nano-domains, the mechanical behaviour becomes size dependent and thus, we cannot expect the classical elasticity solutions to hold. In particular, recent experimental investigations of fatigue strength of metals show pronounced strengthening due to the influences of small geometrical dimensions. Based on second gradient elasticity framework as particularized on beams, closed form solutions to idealized problems of elastic cantilever bending, elastic three-point bending and elasto-plastic torsion have been found, showing considerable stiffening, toughening and hardening, respectively, compared to the classical theory predictions. In these models, the intrinsic material length scale was taken to be constant. Furthermore, we describe a gradient solid with a characteristic length which is not a fixed material parameter but depends on the amount of plastic effective strain amplitude, as obtained from cyclic strain hardening. A respective evolution law is suggested and discussed.
KW - fracture
KW - gradient elasticity
KW - length scales
KW - metal fatigue
KW - size effects
UR - http://www.scopus.com/inward/record.url?scp=84864766651&partnerID=8YFLogxK
U2 - 10.1111/j.1460-2695.2012.01668.x
DO - 10.1111/j.1460-2695.2012.01668.x
M3 - Article
AN - SCOPUS:84864766651
VL - 35
SP - 852
EP - 860
JO - Fatigue and Fracture of Engineering Materials and Structures
JF - Fatigue and Fracture of Engineering Materials and Structures
SN - 8756-758X
IS - 9
ER -