Innovative Sandwiches for Civil Applications

Abstract

Physics and mechanical tests were carried out on innovative sandwiches proposed for civil applications, at the aim to know their performances. The core was obtained by embedding short mineral fibre, in different percentages, in polyurethane matrix. The results of the experimental tests were compared to what obtained on sandwiches made without any reinforcement in the polyurethane core: better behaviours were found in terms of compression strength and elastic modulus, compression energy absorption capability, impact force and energy. Good results were observed in thermal conductivity too. A very large experimental campaign was carried out at the aim to characterize the innovative sandwiches under shear load too. It was not simple to obtain the pure shear strength since the very frequent local compression failures due to the not uniform load distribution under bending tests. So, more than one kind of skin, wood, aluminium and polymeric one, was tested: a glass fibre laminate, 1,5 mm in thickness, was revealed the most appropriate one giving the possibility to have the right load distribution to observe the classical shear failure. Better behaviour was noted also in this field even if it resulted very dependent on the reinforcement percentages

Experimental and analytical model for the penetration and indentation prediction on BFRP laminates under low velocity impacts

“…Varying k 0 until the straight line best fitting the data in the diagram will pass through the origin. In Lopresto et al, 5 this condition was found for GFRP with values of k 0 ¼1.06 mm and c 0 ¼0.931, which were insensitive to t and the diameter of the indenter, D i .…”

“…A modified model 5 for the prediction of the indentation was assessed in the present case. A correlation between the dent depth and the absorbed energy was studied.…”

“…The data in Caprino et al 7 showed that k 0 and c 0 are dependent on the fibre type under concern, being insensitive to the panel thickness and constraint conditions, reinforcement architecture, the orientation of the layers in the laminate, matrix type. In subsequent work, Caprino et al 5 modified the previous formula as follows:…”

Flexural behaviour of fibre-reinforced polymer–aluminium sandwich curtain walls

“…Composite sandwich structures, often consisting of two strong skin sheets and one layer of soft core, are becoming increasingly popular in aerospace, automotive and construction industry owing to their very high performance to weight ratio. Numerous studies were conducted to study the mechanical properties as well as the failure mechanisms of different types of sandwich structures theoretically and experimentally by researchers in different areas [1][2][3][4][5][6][7][8][9].…”

“…Using composite sandwich structures as secondary components, such as curtain walls, is one of the most promising areas in the building and construction industry. Most of the composite sandwich panels that were studied in the published literature have two common features [5][6][7][8][10][11][12]: (a) the cross section of the panel is symmetric, and (b) the skin of the panel is most likely to be fibre-reinforced polymer (FRP) or concrete. However, because a curtain wall is the main non-structural component that separates the indoor environment of a building from outdoor, the service condition is particularly different from that of either indoor or outdoor.…”