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Numerous empirical and numerical studies have been carried out on the mechanical characterization of ductile materials. The application of digital image correlation (DIC) equipped with three-dimensional measurement analysis was used to examine the mechanical characteristics of aluminum alloy (AL 7075). Then, the DIC outcome with finite element simulation results will be compared with the experimental results to measure the performance of the DIC. A tensile specimen of AL 7075 is tested under constant loading with a 2 mm/min displacement rate until fracture. Strain gauge and extensometer are used along with DIC monitoring technique to capture the structural deformation of the specimens. The specimen and test are simulated in ABAQUS software, in which the results are compared with experiment and DIC data, indicating a good correlation between the results. Limited data in the form of average deformation and strain of the experiments are not applicable to the plastic and necking process. In this respect, the 3D DIC results are used to analyze the strain field throughout the test, including specimen necking, and predict fracture location. Moreover, the outcome of DIC and finite element simulation are employed to examine the characteristics of AL 7075 about the large plastic deformation and mechanical behavior. The proposed 3D DIC methodology in providing insight into the characteristic mechanical behavior of ductile materials is highlighted in this paper. [ABSTRACT FROM AUTHOR]

In this study, the unidirectional carbon fiber-reinforced polymer (CFRP) composite laminates under the Mode I loading are characterized using Cohesive Zone Model (CZM). A bilinear traction-displacement softening law is assumed for the interface behavior. The required interlaminar properties and CZM model parameters are characterized through an experimental-finite element (FE) approach. These parameters are the critical Mode I energy released rate, GIC, tensile strength, T and tensile penalty stiffness, kn. For this purpose, a unidirectional, 32-ply ([0]32) double-cantilever beam specimen is tested to fracture. The global load-displacement response of the specimen to the interface crack extension is recorded. The result establishes the Mode I critical energy release rate, GIC = 0.31 N/mm. The validated finite element (FE) simulation of the test is then employed to extract the CZM model parameters corresponding to the observed interlaminar damage initiation event. The FE-calculated maximum normal stress at the interface crack front is taken to represent the tensile strength of the interface, T=62.5 MPa. The corresponding slope of the stress-relative opening displacement of this critical material point indicates the penalty stiffness of the interface, kn = 0.98×106 N/mm3. With the established interfacial properties, the CZM could then be employed in simulating the deformation and damage process of the interfaces in FRP composite laminates under Mode I loading. [ABSTRACT FROM AUTHOR]

This paper establishes the effects of different lay angles of steel wire ropes on the resulting damage modes and fatigue fracture characteristics. For this purpose, seven-wire strand (1×7) wire ropes with left lay arrangement and lay angles, α of 11°, 18° and 24° were simulated using finite element (FE) method. Axial load cycles (Pmax = 0.144 minimum breaking load (MBL), R=0.1) along with the Coulomb friction μ of 0.5 between the contacted drawn steel wires are assumed. Results showed that the peak contact pressure, corresponding to the maximum applied load, varies from 1936 to 327 MPa when the lay angle is changed from 11° to 24°. The peak of the localized pressure, at any applied load level, is also higher for a smaller lay angle. The wire rope with the lay angle of 24° experiences the smallest load-displacement hysteresis loop with the relative displacement range of 22 μm. On the other hand, the wire ropes with the lay angle of 11° and 18° develop larger hysteresis loops with the displacement range of 75 and 48 μm, respectively. The dissipated energy due to the frictional contact is 469 N.mm, 314 N.mm, and 132 N.mm for the lay angle of 11°,18°, and 24°, respectively. In addition, the axial stiffness of the wire ropes decreases with the increase of the lay angle. It is anticipated that the wire rope with the large lay angle of 24° would experience fretting fatigue failure associated with the partial slip, while those with smaller lay angles (α=11°,18°) would fail by fretting wear mechanism under the gross slip condition. [ABSTRACT FROM AUTHOR]