Fatigue strength test of casting material GS-20Mn5V
The Small-sample up and down fatigue test method was used to test the fatigue limit of casting GS-20Mn5V which is the most popular casting material in civil engineering. The symmetric tension-compression fatigue test was on the high frequency fatigue tester. Ten useful test values were obtained through twelve tests with standard specimens. The mean value of fatigue limit of GS-20Mn5V is 202.8MPa after a statistic of the test results. The test provides the available data for engineering application.
Fatigue design of cast steel nodes in tubular bridge structures
Due to their aesthetic and structural advantages, tubular space truss structures are enjoying increasing popularity in modern bridge construction. The use of cast steel nodes for the joints between the circular hollow section members is also becoming increasingly popular. The fatigue design of such joints, however, requires additional knowledge with respect to their fatigue resistance. Previous experimental investigations showed very clearly that the fatigue behaviour is governed by the welds between the casting stubs and the hollow section members. This paper presents a methodology for the determination of allowable initial sizes of casting defects as a function of the required fatigue resistance of the welds. The relative influence of the main parameters is quantitatively discussed and recommendations for design are given.
RELATIONSHIP BETWEEN MATERIAL FRACTURE TOUGHNESS USING FRACTURE MECHANICS AND TRANSITION TEMPERATURE TESTS. Technical Report No. 15.
Although the effect of flaws in stressed bodies can be quantitatively characterized by methods of linear elastic fracture mechanics (LEFM), it is sometimes necessary to assess the fracture susceptibility using only conventional transition temperature tests. In order to gain the advantages and best features of each approach, a correlation between the two methods of fracture assessment is needed. The existing correlation between LEFM results and transition temperature test results are reviewed in light of new data on A533B steel. A complete series of test results obtained by the HSST Program (ORNL) for both LEFM and transition temperature tests in both unirradiated and irradiated conditions permit fracture toughness to be correlated with charpy V-notch energy, nil-ductility transition temperature, DT transition temperature, and low temperature cleavage stress. By following fundamentals of LEFM, whenever possible, a consistent pattern of fracture behavior is demonstrated for a class of pressure vessel steels similar to A533B. /Author/