Plane strain fracture toughness

ASTM E399-90, "Plane Strain Fracture Toughness of Metallic Materials," MnnualBook ofMSTM Standards, ASTM PubHcations, Philadelphia, 1993. 

ASTM D5045-91, "Plane Strain Fracture Toughness and Strain Energy Release Rate of Plastic Materials," A.nnualBook ofyiSTM Standards, ASTM Puhhcations, Philadelphia, 1993. 

Plane Strain Fracture Toughness of Metallic Materials, 1982 Annual Book of ASTM Standards, Part 10, Standard No. E399. 

Note. is the plane strain fracture toughness (see Section 8.9). 

There are a number of restrictions on the test for for it to be a valid measure of plane strain fracture toughness. Firstly, the plastic zone must not extend through the test piece and secondly the thickness of the material must be such that the test is conducted under plane strain conditions. 

ASTM-E 399-81 Standard test method Plane-strain fracture toughness of metallic materials... 

ASTM E399 Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials , 1999 Annual Book of ASTM Standard Volume 3.01 Metals-Mechanical Testing Elevated and Low-Temperature Tests Metallography, American Society for Testing and Materials, 1999. 

Ideally, rubber toughening should be accomplished without substantial sacrifices in modulus. For each modified resin, flexural and Young moduli and plane-strain fracture toughness were determined. Examination of various fracture surfaces by scanning electron microscopy showed the effects of modifier composition on the morphology of these multi-phase materials as well as the prominent features of the fracture process. 

Fracture toughness for siloxane-modified as well as ATBN- and CTBN-modified resins was monitored through KIC, plane-strain fracture toughness 44). The Klc values of at least five three-point bend (3PB) specimens of each material were calculated according to Eq. (1)... 

In the case of thin sections the measure of toughness is given by plane-stress fracture toughness, Kc and elastic-plastic fracture mechanics (EPFM) are used. It is also necessary to bear in mind that plane-stress fracture toughness Kc is higher than plane-strain fracture toughness Xlc. 

E399, Standard Test Method for Plane-strain Fracture Toughness of Metallic Materials, ASTM, West Conshohoken, PA, 1997. 

ASTM E 299-71, Standard Method of Test for Plane-Strain Fracture Tough-... 

Figure 15. (a) Variation of plane strain fracture toughness with rubber content for samples with an epoxy-to-polyester ratio of 1 2. Compact tension specimens were tested at 0.2 in./min. using ASTM E-399. (b) Variation of strain-energy release rate, GJc, with rubber content for samples with an epoxy-to-polyester ratio of 1 2. 

The plane strain fracture toughness was determined using ASTM E-399 with compact tension specimens. Specimens were precracked using a razor blade. The ratio of the precrack length to the total length of the sample was kept within the specified limits. Only samples with straight precracks were used for testing, which was done at a rate of 0.2 in./min. 

KIc, plane-strain fracture toughness (eqs 1, 2) was used to calculate the fracture toughness, where Y is the shape factor, P is the load to failure, S is span of the Instron supports. 

The development of practical specimens and procedures for determining plane strain fracture toughness was carried out during the late 1950s and 1960s, largely... 

For this penny-shaped crack model specimen, the crack diameter would be the only dimension of concern the other dimensions would be taken to be very large. The crack size requirement may be considered by writing the effective crack diameter 2a in terms of the plane strain fracture toughness Kic and the yield strength ys of the material by using Eqn. (4.7) i.e., for the conceptual case where yielding and fracture occur concurrently. 

In this case, the crack size is much larger than the plane strain crack-tip plastic zone size. As such the effective crack length 2a = 2ao + 2rjy would be effectively equal to the initial (or physical) size of the crack 2ao. The load-displacement trace would be essentially hnear up to the point at which the specimen fractures abruptly (see Fig. 4.5a). The plane strain fracture toughness Kic can be computed directly from the maximum load Pmax or stress a ax i e., the load or stress at fracture) and the initial crack size ao using Eqn. (4.7). 

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