The ability of a material to resist cracking, or fracture, has been vital to the studies of fracture mechanics. Until recently the study of fracture toughness has been analyzed at a macro range using powerful instrumentation applied to large samples.
The use of Microindentation has proven to be a crucial tool for rock mechanics related studies. For example, Microindentation has been used to advance studies in excavation by allowing further understanding of rock mass properties and its separation. Microindentation has been used to advance drilling studies to improve drill heads and improve drilling procedures. Microindentation has also been used to study chalk and powder formation from minerals.
HI, everyone,
This is pflines, i am working on the mode I\II fracture toughness.
i want to use the asymmetric four-point-bend sepcimens to get the value of KI and KII,
but did not found a clear formulation to caculate the KI and KII,
anyone could help me?
Hi everybody,
I have done some experiments on the fracture toughness in mode II of wood specimens using attached geometry;so using
formula KIIc= 5.11P(3.1415*a)^0.5 /(2BW) I was able to calculate the frcature toughness of wood, but I am quite suprised
why this equation does not iclude depth of the specimens and moreover, I think that I have obtained higher values for the
fracture toughnes values. Is there any other formulation for obtaining the fracture toughness in mode II for this specimen?
P.s. dimension of my specimens is 100*100*63mm
When a bi-material sample for the characterization of interfacial fracture toughness is manufactured, the sample is not usually stress-free at room temperature. If an interface between a metallic substrate and a polymeric adhesive is considered, there are essentially two sources of residual stresses for a dry sample at room temperature:
1- The mismatch between the Coefficient of Thermal Expansion (CTE) of adhesive and substrate induces a concave or convex warpage, depending on the CTE values of the two materials.
