Residual stress measurement of fiber metal laminates using incremental hole-drilling technique in consideration of the integral method

Abstract

In this manuscript, integral method was used for the approximation of residual stresses field in fiber-metal laminates (FMLs). Initially, calibration coefficients matrix for the integral method were determined numerically by the finite element program using ANSYS software. The calibration coefficients were used to relate the measured strains relaxation field with the existing residual stresses prior to the IHD process. Subsequently, FML specimens with symmetric stacking sequence of were manufactured. Next, the IHD experiment by high speed drilling machine were performed and released strains caused by the change in hole-geometry have been obtained. Finally, experimental results from IHD experiment were compared with the theoretical predictions from classical lamination theory. Very good agreements with the experimental and theoretical results show that, the IHD technique can be successfully applied for measuring residual stresses in FML composites.

Residual stress and failure analyses of polymer matrix composites considering thermal cycling and temperature effects based on classical laminate plate theory

“…Studies have proved that the free stress temperature is often 15 C more than the curing temperature. 22,23 Problem formulation…”

“…Also, k is the lamina number; Q(k) is the stiffness matrix in off-axis coordinate system, Δ T is the temperature difference between the instance and the stress-free temperatures and α (k) is the vector of CTE in off-axis coordinate system. The strain and the curvature of mid-plane are determined as follows 23 where ɛ· and k· are normal strain and curvature of the mid-plane, respectively. Figure 2 shows the geometry of a polymer composite plate where A , B , and D are the extensional, coupling, and bending stiffness matrixes, respectively, and defined as 24

Figure 2.A multi-layer polymer composite plate.

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“…In order to calculate the residual strain of the k th layer, equation (4) is proposed. After that the residual stress of the kth layer of PMCs can be obtained as follows 23 …”

Ball-burnishing effect on deep residual stress on AISI 1038 and AA2017-T4

“…A second application of FEM simulations is necessary to estimate the errors introduced by the drill eccentricity with respect to the rosette center, as reported by several authors such as Svarıcek and Vlk [41], Ghasemi and Mohammadi [42] and Schuster and Gibmeier [43]. This step is recommended, for the standard sets a maximum eccentricity of 0.004D ¼ 0.052 mm.…”

Effect of cutting parameters on surface residual stresses in dry turning of AISI 1035 alloy

“…Many attempts have been done to figure out the relationship between different cutting parameters/conditions and the induced RSes using experimental [6][7][8], analytical modeling [9][10][11], finite element modeling [12][13][14], and various combinations of them [15][16][17] in various machining operations [18][19][20]. The experimental investigations were carried out via measuring the RSes using different measuring methods such as ring core method [21], hole drilling technique [22], deep-hole drilling [23], slope cutting method [24], contour method [25], synchrotron diffraction [26] method, XRD method [27], and neutron diffraction method [28]. Among all these measuring techniques, XRD and hole drilling technique are the most commonly used in machining applications.…”