Abstract
In this paper, an elastoplastic analysis model of thin‐walled circular tubes under the combined action of axial force and torque is discussed. Based on the von Mises yield criterion and the assumption of isotropic linear hardening, the methods of stress path and strain path loading are analyzed to study the effect of combined tensile‐torsional loading path on thin‐walled circular tubes. A finite element model is used to analyze the loading path effect on thin‐walled circular tubes. A series of tensile and torsional tests are also carried out on 304 stainless steel thin‐walled circular tubes using a universal testing machine. In addition, the consistency of the selected material with the von Mises yield criterion, the assumption of isotropic linear hardening, and other classical elastoplastic mechanics are verified. The theoretical calculation results, the numerical analysis results, and the experimental test results are analyzed and compared. The “primary effect” influenced by the stress path and the “recency effect” affected by the strain path are proved, and their application prospects are discussed. The influence of tensile‐torsional loading path on the final stress and strain states of thin‐walled circular tubes after entering the plastic deformation stage is concretely demonstrated, facilitating the understanding of the principles of the aforementioned two effects. The investigation for a general principle concerning the effect of loading history on the mechanical behavior of engineering materials, based on the classical plastic mechanics, has an important theoretical significance. It is of great theoretical importance for advancements in plastic yield theory and the establishment of more accurate loading conditions suitable for specific materials in engineering practice.
Highlights
ANSYS 19.2 Workbench was used for finite element analysis (FEA) of the model under different loading paths. e MTS809 tensile-torsional combined material testing system was used to measure the strain results of the standard specimens under different stress loading paths
C. e average values of σz (SZ) and τθz (SYZ) of Selection 1 were calculated based on the cylindrical coordinate system, the stress paths of which are shown in Figures 13(a)–13(c). e stress paths of σz and τθz obtained according to the loading scheme shown in Figure 11 meet
Based on classical elastoplastic mechanics theory, finite element analysis and experimental verification of the effect of loading path in the tension and torsion problems of thinwalled circular tubes were carried out in this study. e similarities and differences of the results obtained from theoretical calculations, finite element analyses, and experimental tests were analyzed
Summary
E theory and testing techniques for the stress and strain of a thinwalled circular tube under pure axial tension or torsion are mature, while the experimental research on the corresponding mechanical properties of the thin-walled circular tube showed great differences due to the complexity of the loading combined deformation. Wang et al [3] carried out tensiletorsional fatigue tests and finite element theoretical calculations on No 45 steel thin-walled circular tube specimens containing holes, analyzed their fatigue characteristics, and predicted service life. Chaves et al [4] carried out tensile, torsional, and tensile-torsional tests on 304 stainless steel thin-walled circular tube specimens with perforations and investigated fatigue limit and crack propagation direction. Ey showed that the results obtained for uniaxial tensile and biaxial combined tensile-torsional nonproportional tests using the proposed model were in good agreement with corresponding experiments. Zhang et al [7] developed a new image-based single-camera tensile-torsional strain measurement method. e results obtained by this method were compared with those of DIC (digital image correlation) through experiments, which proved the reliability of this method
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