SU1227975A1 - Prismatic piece for material toughness test - Google Patents

Abstract

The invention relates to testing the viscosity of fracture in a complex stress state arising from contact loads. In order to ensure that the specimen remains unchanged in the crack propagation zone on a prismatic specimen, symmetrical notch planes of the thickening are performed, through which the specimen is loaded with a contact load. The width a and height b of the bulges satisfy the relation b, where 8 is the height of the sample without bulges, 1 slug. with (L S

Description

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The invention relates to the investigation of the strength properties of materials, namely, prismatic samples for testing materials on the fracture toughness.

The purpose of the invention is to improve the accuracy of testing by ensuring that the specimen remains unchanged under the action of contact forces.

The drawing shows schematically the proposed test specimen.

In the prismatic sample, an incision 2 is made on the top face 1. Symmetrically the notch plane 2 on the top face 1 is made thickenings 3 and 4, and on the bottom face 5 - thicknesses 6 and 7. Each of the thickenings 3,4, 6 and 7 has a width a and height b, which satisfy the relation, where B is the height of the specimen without bulges.

Before testing, a fatigue crack 8 is grown from the tip of notch 2 in the sample,

The material is tested under the simultaneous action of a bending moment M and contact stresses, which are created in the zone of a crack 8 by means of forces P applied, for example, through contact rollers (not shown). During loading, the forces, loading time, crack length are recorded and, according to the measurement results, the fracture toughness of the sample material is judged.

Example. Prismatic samples from normalized steel 20 with dimensions 9x18x200 mm were tested.

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The thickenings had dimensions: mm, mm. The cracks were made 2-10 mm in size. In addition, the same sample was tested without nodules.

5 As a result of the intakes, it was found that the compliance of the specimen with thickenings is less than that of the specimen without thickenings. Moreover, if the height b of the bulges exceeds

 About the value of B / Z, then a further increase in b has practically no effect on the change in the compliance of the samples, the contact stresses are localized in the thickeners themselves and do not affect

15 on the pattern of deformation of the sample with a crack.

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Claims (1)

Invention Formula A prismatic specimen for testing the viscosity of fracture under the simultaneous action of bending and contact stresses, having in the plane perpendicular to the axis of the specimen an edge notch with a crack at its apex, characterized in that in order to increase the accuracy of the specimen under the action of contact forces, on the upper and lower faces of the sample, symmetrically, the notch plane has thickenings with width a and height b, which satisfy the relation, where B is the height of sample b of nodules. Invention Formula five 0 five A prismatic specimen for testing the viscosity of fracture under the simultaneous action of bending and contact stresses, having in the plane perpendicular to the axis of the specimen an edge notch with a crack at its apex, characterized in that in order to increase the accuracy of the specimen by ensuring a constant specimen compliance under the action of contact forces, on the upper and lower faces of the sample, symmetrically, the notch plane has thickenings with width a and height b, which satisfy the relation, where B is the height of sample b of nodules. / Compiled by M. Kuzmin Editor V. Kovtun Tehred N.Vonkalo Order 2281/43 Circulation 778 Subscription VNISH1I USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4