PSI - Issue 16

Róbert Beleznai et al. / Procedia Structural Integrity 16 (2019) 59–66 Róbert Beleznai et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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3. Finite element model of the composite bridging element

3.1. Mechanical analyses

The two main features of a bridging element are the load bearing capacity and heat insulation properties. Rebar type element in the reinforced lintel is used for cane modelling. The Rebar element is a superposition of two different elements that can be applied for composite material modelling: the matrix material is given with volumetric elements while the reinforcement fibres are defined with beam elements in the same volume. The mechanical and thermal composite properties depend on the properties and content of the components of the composite material thus, the numerical simulations are performed with three different compositions (Fig. 1) to investigate the influence of the composite structure. The first version of the composite contains 4.76 per cent of cane, the second version has 19.05 per cent of the reinforcing elements, and the third version has the highest content, 28.57 per cent of volume ratio.

4.76 % of the volume ratio

19.05 % of the volume ratio

28.57 % of the volume ratio

Fig. 1. Finite element model for the different volume ratio of the reinforced fibres.

The size of the bridging element is 125 × 125 × 1300 mm, which can be modelled as a beam fixed at both ends. It means that displacement in three directions ( x , y , z ) is constrained of 200 mm in length (upper, lower and end surfaces). The applied load according to the catalogue of Solbet company (see http://www.solbet.hu/athidalok) is 22.000 N/m of distributed load that can be defined on the top of the bridging element between the supporting walls.

3.2. Results of the numerical simulation

The obtained equivalent Cauchy stress is 8 MPa and the maximum value of the deflection is 0.56 mm in the cross-section of the middle of the bridging element in case of 4.76 volume ratio. The analysis of the stress state of the reinforcement elements showed that the tensile stress of 3 MPa occurs at the upper part of the bridging element while 4 MPa compression stress appears at the lower part. The results of the simulation considering 19.05 per cent of cane content indicate the equivalent Cauchy stress of 4.3 MPa and the maximum deflection of 0.52 mm in the middle of the bridging element. The tensile stress of 2.4 MPa occurs in the cane fibres at the upper part of the bridging element while 2.8 MPa compression stress is observed at the lower part. The maximum volume ratio is 28.57 per cent what can be achieved with the size of the available cane fibres. The obtained equivalent Cauchy stress is 3.2 MPa and the maximum value of the deflection is 0.50 mm in the cross section of the middle of the bridging element in case of 4.76 volume ratio (Fig. 2). From the results of the analysis of the stress state of the reinforcement elements it is concluded that the tensile stress (2 MPa) occurs at the upper part of the bridging element, while the compression stress (2.3 MPa) appears at the lower part.