ASTM D3433-99(2012)
粘结金属接头中胶粘剂的断裂强度的标准试验方法

Standard Test Method for Fracture Strength in Cleavage of Adhesives in Bonded Metal Joints

被代替

标准号

ASTM D3433-99(2012)

发布

1999年

发布单位

美国材料与试验协会

替代标准

ASTM D3433-99(2020)

当前最新

ASTM D3433-99(2020)

 

 

引用标准

ASTM A167 ASTM A366/A366M ASTM B152/B152M ASTM B209 ASTM B265 ASTM B36/B36M ASTM D907 ASTM E399 ASTM E4

适用范围

5. Significance and UseTop Bottom

Note 2???Crack growth in adhesive bond specimens can proceed in two ways: (1) by a slow-stable extension where the crack velocity is dictated by the crosshead rate or (2) by a run-arrest extension where the stationary crack abruptly jumps ahead outrunning the crosshead-predicted rate. The first type of crack extension is denoted flat; the second type peaked because of the appearance of the autographic record. The flat behavior is characteristic of adhesives or test temperatures, or both, for these adhesives where there is no difference between initiation, G_1c, and arrest, G_1a. For example, the rubber modified film adhesives tested above8201;???8201;17.8??C (0??F) all exhibit flat autographic records. Peaked curves are exhibited for all modified materials tested below ???73??C (???100??F) and in general for unmodified epoxies.

It should be noted that both peaked and flat behaviors are determined from a crack-length-independent specimen. For other specimens or structures where G increases with a at constant load the onset of crack growth would result in rapid complete fracturing whatever the adhesive characteristics.

5.1 The property G_1c (and G_1a if relevant) determined by this test method characterizes the resistance of a material to slow-stable or run-arrest fracturing in a neutral environment in the presence of a sharp crack under severe tensile constraint, such that the state of stress near the crack front approaches tritensile plane strain, and the crack-tip plastic region is small compared with the crack size and specimen dimensions in the constraint direction. It has not been proven that tough adhesive systems fully meet this criteria. Therefore, data developed using equations based on this assumption may not represent plane-strain fracture values. Comparison of fracture toughness between adhesive systems widely different in brittleness or toughness should take this into consideration. In general, systems of similar type toughness (3, 4, 7, 8, 10) can be compared as can the effect of environment on toughness of a single system. A G_1c value is believed to represent a lower limiting value of fracture toughness for a given temperature, strain rate, and adhesive condition as defined by manufacturing variables. This value may be used to estimate the relation between failure stress and defect size for a material in service wherein the conditions of high constraint described above ......

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