Fatigue apparatus for geometrically complex non-standardized specimens
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Data
2009-01-01
Autores
Nascimento, Marcelino P. [UNESP]
Voorwald, Herman J.C. [UNESP]
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Resumo
Standard Test Methods (e.g. ASTM, DIN) for materials characterization in general, and for fatigue in particular, do not contemplate specimens with complex geometries, as well as the combination of axial and in-plane bending loads in their methodologies. The present study refers to some patents and the new configuration or configurations of specimens (non-standardized by the status quo of test methods) and a device developed to induce axial and bending combined forces resultants from axial loads applied by any one test equipment (dynamic or monotonic) which possesses such limitation, towards obtaining more realistic results on the fatigue behavior, or even basic mechanical properties, from geometrically complex structures. Motivated by a specific and geometrically complex aeronautic structure (motor-cradle), non-standardized welded tubular specimens made from AISI 4130 steel were fatigue-tested at room temperature, by using a constant amplitude sinusoidal load of 20 Hz frequency, load ratio R = 0.1 with and without the above referred auxiliary fatigue apparatus. The results showed the fatigue apparatus was efficient for introducing higher stress concentration factor at the welded specimen joints, consequently reducing the fatigue strength when compared to other conditions. From the obtained results it is possible to infer that with small modifications the proposed apparatus will be capable to test a great variety of specimen configurations such as: squared tubes and plates with welded or melted junctions, as well as other materials such as aluminum, titanium, composites, polymeric, plastics, etc. © 2009 Bentham Science Publishers Ltd.
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Palavras-chave
Combined in-plane bending moment and axial loadings, Fatigue apparatus, Hot-spot stress concentration factor, Non-standardized specimens, Welded tubular specimens, Aeronautic structures, AISI 4130 steel, Axial loading, Combined forces, Complex geometries, Complex structure, Constant amplitude, Fatigue behavior, Fatigue strength, Hot-spot stress, In-plane bending, In-plane bending moment, Load ratio, Materials characterization, Room temperature, Sinusoidal load, Standard test method, Stress concentration factors, Test equipments, Test method, Tubular specimens, Axial loads, Bending (deformation), Bending moments, Crack initiation, Fatigue of materials, Mechanical properties, Pipeline bends, Stress analysis, Titanium, Welding, Stress concentration
Como citar
Recent Patents on Mechanical Engineering, v. 2, n. 1, p. 48-54, 2009.