抄録
This paper summarizes the results of tests on two series of T-shaped structural parts reinforced with right-angled triangular ribs. Studies were made in these cases of the effect of various factors on the stress concentration at the reentrant corner formed by the ribs and their members by using the two-dimensional photoelastic method.
Some of the conclusions resulting from these studies are given below.
1. In the case where the member has a rectangular projection and subjected to pure bending:
(a) Neither the height nor the width of the projection affect the stress concentration factor.
(b) The stress concentration factor increases with the increase in the height of the member in a way of decreasing rate and finally approaches a certain value, but it increases drastically when the thickness of the member becomes larger than that of the rib.
(c) If the side of the rib attached to the projection is shortend, keeping the side attached to the member constant, the stress concentration factor at the reentrant corner in the member decreases, while the stress concentration factor in the projection increases. It is considered therefore that there might exist such geometry of a rib as the stress concentration factors at both reentrant corners become equal.
(d) When a structural part is reinforced with two ribs of similar geometry, the ribs of quite the same dimensions should be used so that the stress concentration factor in each reentrant corner is equal.
2. In the case where two members form the T-shaped structural part:
(a) In the case where the member 1 is supported at both ends and the other member 2 is subjected to tensile force, (see Fig. 5(a)), the stress concentration factor in the member 1 increases with the decreasing fillet radius, but it is neither influenced by the dimention of the rib nor by the magnitude of the shearing force.
(b) When both the members are subjected to bending, the stress concentration factor at the reentrant corner B is smaller than that at C (see Fig. 2 and Fig. 5(b)). The stress concentration factor at B decreases as the dimension of the ribs increases, but the stress concentration factor at C is not influenced by the dimension of the rib.
