Residual Strength and Fatigue Lifetime of ... - Solid Mechanics
Residual Strength and Fatigue Lifetime of ... - Solid Mechanics Residual Strength and Fatigue Lifetime of ... - Solid Mechanics
(DIC) measurement system (ARAMIS 2M) was used to monitor 3D surface displacements and surface strains during the experiments. Testing of the columns was conducted using ramp displacement control with a piston loading rate of 0.5 mm/min. A sample rate of one image per second was used in the DIC measurements. Three replicate tests were conducted for each specimen configuration. The material properties of the face sheets, assumed to be in-plane isotropic, were determined by tensile tests based on the ASTM standard D3039. The compression strength of the face sheets was measured on laminate specimens cut from the actual sandwich face sheet using the ASTM standard IITRI (D3410) test fixture. Core material properties were obtained from the manufacturer (DIAB, Divinycell H Technical Data, Labholm), see Table 2.1. Symbols E and G represent Young’s and shear moduli, Poisson’s ratio, max the compression strength of the core and the tensile and compression strengths of the face sheets. GIC is the mode I fracture toughness of the core material (Li and Carlsson, 1999). 2.1: Face and core material properties from experiments conducted on samples from the face sheet and fracture toughness, from Li and Carlsson (1999). Material E (MPa) G (MPa) max (MPa) GIc (J/m 2 ) Face: E-glass/epoxy 10360 3816 0.31 168 (T)/ 95.4 (C) N/A Core: H45 50 15 0.33 0.6 (C) 150 Core: H100 135 35 0.33 2 (C) 310 Core: H200 240 85 0.33 4.8 (C) 625 Figure 2.1: A column test specimen with H100 core and 38.1 mm debond. 18
Figure 2.2: (a) Schematic representation of test fixture (b) actual test setup. 2.3 Experimental Results Figure 2.3 shows typical load vs. axial displacement and load vs. out-of-plane displacement curves for columns with a 50.8 mm debond and H45, H100 and H200 cores. The out-of-plane deflection refers to the centre of the debond, for additional results see Apendix A. Load (kN) 10 8 6 4 2 0 (a) H200 H100 H45 (a) 0 0.2 0.4 0.6 0.8 1 Axial displacement (mm) Figure 2.3: (a) Load vs. axial displacement (b) out-of-plane deflection at the debond centre vs. load for columns with a debond length of 50.8 mm. Figure 2.3 (a) shows that the columns respond in a fairly linear fashion after the initial stiffening region until collapse. Figure 2.3 (b) shows that the out-of-plane deflection increases slowly with increasing load until the maximum load. It will later be shown that the point of maximum load 19 3 Out-of-plane deflection (mm) 2 1 0 (b) H200 H100 H45 (b) 0 5 Load (kN) 10
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- Page 10 and 11: Synopsis Sandwich kompositter er i
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- Page 14 and 15: Contents Preface Executive Summary
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Figure 2.2: (a) Schematic representation <strong>of</strong> test fixture (b) actual test setup.<br />
2.3 Experimental Results<br />
Figure 2.3 shows typical load vs. axial displacement <strong>and</strong> load vs. out-<strong>of</strong>-plane displacement<br />
curves for columns with a 50.8 mm debond <strong>and</strong> H45, H100 <strong>and</strong> H200 cores. The out-<strong>of</strong>-plane<br />
deflection refers to the centre <strong>of</strong> the debond, for additional results see Apendix A.<br />
Load (kN)<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
(a)<br />
H200<br />
H100<br />
H45<br />
(a)<br />
0 0.2 0.4 0.6 0.8 1<br />
Axial displacement (mm)<br />
Figure 2.3: (a) Load vs. axial displacement (b) out-<strong>of</strong>-plane deflection at the debond centre vs.<br />
load for columns with a debond length <strong>of</strong> 50.8 mm.<br />
Figure 2.3 (a) shows that the columns respond in a fairly linear fashion after the initial stiffening<br />
region until collapse. Figure 2.3 (b) shows that the out-<strong>of</strong>-plane deflection increases slowly with<br />
increasing load until the maximum load. It will later be shown that the point <strong>of</strong> maximum load<br />
19<br />
3<br />
Out-<strong>of</strong>-plane deflection<br />
(mm)<br />
2<br />
1<br />
0<br />
(b)<br />
H200<br />
H100<br />
H45<br />
(b)<br />
0 5<br />
Load (kN)<br />
10
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