武汉亚洲心脏医院主页:帮翻译一下

Figures 4-9 show the test results of flange to tube samples with and without joint preparation. Important data can be taken from these figures. For dimensioning the joints to be welded, the diagrams are made available in consideration of sets of IIWrules (Refs.13,14). Evaluations of investigations into the fatigue strength show similar results as in Wohler’s examinations. This means that Wohler’s and Gassner’s diagrams indicate similar curvature characteristics independently of the welded joints examined. Figures 4 and 5show Wohler’s and Gassner’s curves for torsion and bending loads. A dominating influence of the welded shapes could not be determined in the test conditions mintioned above . Wohler’s curves fo the HV welds are nearly identical to his curves of the HY welds subjected to only dynamic bending and dynamic torsion loads .The allowable nominal stress is larger in pure bending than in pure torsion(Fig.4,5).Pure torsion load in large nominal stress amplitudes leads to a short life cycle.However ,in constant amplitudes ,the stress ratio(R=-1 and R=0 ) does not have significant influence on Wohler’s curve of the construction samples.Nevertheless,in variable amplitudes,the construction samples fail with R=0 rather than with R=-1.Nearly all welded joints exhibit failure in the transition of the welded joints to the tube .It can generally be realized that weld shapes with and without joint preparation (HV and HY fillet-welded joints) subjected to torsion and bending loads have no significant influences on the fatigue strength of the samples.Figures 8 nad 9 show the macro and fracture pictures of fillet weld joints as well as the critical regions,respectively. As seen in Fig.3,the joint transition notches 1 in bending loads,the critical location 2 in subjection to torsion ,and the critical region 3 in tension and compression are the most strongly endangered .Furthermore ,the hardness values in these regions are clearly higher,nearly double the hardness values of the basic material.In the butt-joint welds,the welded joints and material transitions also have critical places in the root and coat layers.