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

Thank you,

Parisa

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:

One file is attached.