Search results
Results From The WOW.Com Content Network
When a test fails to meet the thickness and other test requirements that are in place to ensure plane strain conditions, the fracture toughness value produced is given the designation . Fracture toughness is a quantitative way of expressing a material's resistance to crack propagation and standard values for a given material are generally ...
The fracture toughness and the critical strain energy release rate for plane stress are related by = where is the Young's modulus. If an initial crack size is known, then a critical stress can be determined using the strain energy release rate criterion.
The degree of crack blunting increased in proportion to the toughness of the material. [4] This observation led to considering the opening at the crack tip as a measure of fracture toughness. The COD was originally independently proposed by Alan Cottrell and A. A. Wells. [5] [6] This parameter became known as CTOD. G. R.
This new material property was given the name fracture toughness and designated G Ic. Today, it is the critical stress intensity factor K Ic, found in the plane strain condition, which is accepted as the defining property in linear elastic fracture mechanics.
where is the fracture toughness, ′ = / for plane strain and ′ = for plane stress. The critical stress intensity factor for plane stress is often written as K c {\displaystyle K_{\rm {c}}} . Examples
Figure 7.1 Plane stress state in a continuum. In continuum mechanics, a material is said to be under plane stress if the stress vector is zero across a particular plane. When that situation occurs over an entire element of a structure, as is often the case for thin plates, the stress analysis is considerably simplified, as the stress state can be represented by a tensor of dimension 2 ...
The stress intensity factor at the crack tip of a compact tension specimen is [4] = [() / / + / / + /] where is the applied load, is the thickness of the specimen, is the crack length, and is the effective width of the specimen being the distance between the centreline of the holes and the backface of the coupon.
The major surface strain has a minimum value when plane strain deformation occurs, which means that the corresponding minor surface strain is zero. Forming limits are a specific material property. Typical plane strain values range from 10% for high-strength grades and 50% or above for mild-strength materials and those with very good formability.