Mechanical Properties in Notched AS-4/PEEK APC-2 Composite Laminates at Elevated Temperature

Abstract

The response of centrally notched AS-4/PEEK APC-2 composite laminates at elevated temperatures is investigated empirically and systematically. The failure mechanism and mechanical properties in notched cross-ply and quasi-isotropic laminates are perceived. First, the ultimate strength decreases seriously as the hole diameter increases, whereas the longitudinal stiffness changes irregularly. Next, combined with the effect of temperature elevation, the ultimate strength is accelerated to decay while the longitudinal stiffness is reduced slowly. Neglecting the increase in longitudinal stiffness, the worst case of both lay-ups as expected with the largest hole diameter and at the highest temperature still sustains at least 60% of ultimate strength. However, the reduction of strength in cross-ply laminates is more serious than that in quasi-isotropic laminates. Finally, a modified predictive model was proposed and found satisfactorily acceptable. It is also highlighted as a reliable, general, and simple model.

Tensile behaviors of layer-to-layer 2.5D angle-interlock woven composites with/without a center hole at various temperatures

“… 20 , where the residual stress at elevated temperature was enhanced compared to that at room temperature. Additionally, when the temperature remains constant, the load-carrying capacity of open-hole 2.5DWC gradually decreases with the increase of hole size, which is consistent with the open-hole laminated composites 29 , 37 . Nevertheless, the extension of reduction induced by the enlargement of hole size is not significant at 240 °C, indirectly suggesting that the temperature plays a major role in the mechanical response at 240 °C.…”

“…As a new category of lightweight woven composites, layer-to-layer 2.5D angle-interlock woven composites have a potential application in the field of aerospace engineering such as fan blade and aero-engine case due to the advantages over the conventional laminated composites, including through-thickness reinforcement, high damage tolerance and advanced anti-fatigue characteristic 5 , 6 . However, some composite structures expose to long-term temperatures in 100–200 °C such as aero-engine casing, which requires that resin matrix composites have a temperature-resistant capacity 7 – 11 .…”

About the influence of temperature and matrix ductility on the behavior of carbon woven-ply PPS or epoxy laminates: Notched and unnotched laminates

“…Around their T g , the nonlinear behavior of fiber-reinforced polymer composites becomes significant, especially under off-axis loading conditions. This nonlinear response, associated with the shear deformation of the polymer matrix along reinforcing fibers, is enhanced at high temperature depending on the matrix viscoplastic -3 nature [4][5][6][7][8][9]. Very few studies have investigated the high-temperature behavior of PPSbased laminates [10][11][12][13][14] or woven-ply epoxy laminates [15][16][17].…”

Determination of residual strength in notched APC-2 cross-ply composite laminates at elevated temperature

“…Therefore, a modified diaphragm-curing process, as shown in Figure 1, was adopted herein. 18 A 250 Â 150 mm panel was fabricated. A water-cooled cutting machine with a diamond blade was used to cut the panel into 240.0 mm (L) Â 25.4 mm (W) Â 2.0 mm (t) specimens consistent with American Society for Testing and Materials (ASTM) D3039-93.…”

“…17 The variable of temperature has been successfully added to the modified PSC model, and this extended modified PSC model was consistent with the experimental data herein. 18 The modified PSC model was successfully extended to severe environmental conditions, including elevated temperatures. Because this extended modified PSC model can be used by less experimental data, it may help engineers in reducing the cost on experiments.…”