A Macroscopic Strength Criterion for Isotropic Metals Based on the Concept of Fracture Plane

Abstract

Although the linear Mohr–Coulomb criterion is frequently applied to predict the failure of brittle materials such as cast iron, it can be used for ductile metals too. However, the criterion has some significant deficiencies which limit its predictive ability. In the present study, the underlying failure hypotheses of the linear Mohr–Coulomb criterion were thoroughly discussed. Based on Mohr’s physically meaningful concept of fracture plane, a macroscopic strength criterion was developed to explain the failure mechanism of isotropic metals. The failure function was expressed as a polynomial expansion in terms of the stresses acting on the fracture plane, and the quadratic approximation was employed to describe the non-linear behavior of the failure envelope. With an in-depth understanding of Mohr’s fracture plane concept, the failure angle was regarded as a generalized strength parameter in addition to the failure stress (i.e., the conventional basic strength). The undetermined coefficients of the non-linear failure function were calibrated by the strength parameters obtained from the common uniaxial tension and compression tests. Theoretical and experimental assessment for different types of isotropic metals validated the effectiveness of the proposed criterion in predicting material failure.

Failure Mechanisms in Alloys

“…More specifically, the broad category of static overload includes more generic subjects also from the field of manufacturing-related topics, where the effect of deformation and fracture was studied as an important and undetached ingredient of the fabrication process per se (e.g., hot and cold working, machining). Therefore, the mostly "intense area" (Overload/Static) comprises studies concerning general deformation and fracture phenomena, as the result of instant loading/testing conditions [4,9,10,14,15,19] and studies related to manufacturing and production processes [6,7,12,13,16,20,22,25,26]. Testing and modeling procedures addressing the evolution of deformation and fracture during forming [7,13,26], the impact toughness, [4] and certain production process characteristics [25] are also included.…”

“…1. Phenomenological and Experimental [1][2][3][4][5][6][7][8][9][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] 2. Numerical Modeling [6,7,10,12,13,15,25,26] 3.…”

“…Based on the "Investigation Method/Approach", several broad categories can be distinguished (Figure 4 Combined (experimental, analytical, numerical model, etc.) [3,[6][7][8][12][13][14][15][16][18][19][20]22,25,26] As can be readily observed, the experimental and empirical approach is the dominant methodology of failure investigation. In addition, the emergence of numerical simulation, using finite element modeling (FEM), tends to be very popular in the prediction of material behavior and potential failure prevention.…”

Failure Mechanisms in Alloys

“…Combined (experimental, analytical, numerical model, etc.) [3,[6][7][8][12][13][14][15][16][18][19][20]22,25,26] As can be readily observed, the experimental and empirical approach is the dominant methodology of failure investigation. In addition, the emergence of numerical simulation, using finite element modeling (FEM), tends to be very popular in the prediction of material behavior and potential failure prevention.…”

“…Reference Structural and pipeline steels [1,5,9,13,16,20,22,27] Cast iron [14,19] Special resistance and stainless steels [3,4,9,11,17,18,21,23,24] Wear resistant coatings and surface layers [24,27]…”