Box beam

Closed box-beam example defined directly in the XML input.

Overview

Figure 17 Cross section of the box beam.

This example is a thin-walled box beam cross-section. The width \(a_2=0.953\) in, height \(a_3=0.530\) in, and thickness \(t=0.030\) in. Each wall has six plies of the same composite material and the same fiber orientation of \(15^\circ\). Material properties and layup scheme are listed in Material properties and Layups.

Table 10 Material properties

Name	Density	\(E_{1}\)	\(E_{2}\)	\(E_{3}\)	\(G_{12}\)	\(G_{13}\)	\(G_{23}\)	\(\nu_{12}\)	\(\nu_{13}\)	\(\nu_{23}\)
	\(\mathrm{lb\cdot sec^2/in^4}\)	\(10^6\ \mathrm{psi}\)	\(10^6\ \mathrm{psi}\)	\(10^6\ \mathrm{psi}\)	\(10^6\ \mathrm{psi}\)	\(10^6\ \mathrm{psi}\)	\(10^6\ \mathrm{psi}\)
mat_1	0.0001353	20.59	1.42	1.42	0.87	0.87	0.696	0.30	0.30	0.34

Table 11 Layups

Name	Layer	Material	Ply thickness	Orientation	Number of plies
			\(\mathrm{in}\)	\(\circ\)
layup1	1	mat_1	0.05	-15	6

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Input

• box_cus.xml

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Run the example

prevabs -i box_cus.xml --hm

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Output

Figure 18 Cross section viewed in gmsh.

• box_cus.png

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Analysis Result

Cross-sectional properties are given in Results and compared with those in Ref. [YU2012]. The tiny differences are due to different meshes.

Table 12 Results

Component	Value	Reference [YU2012]
\(S_{11}\) [\(\mathrm{lb}\)]	\(\phantom{-}1.437 \times 10^6\)	\(\phantom{-}1.437 \times 10^6\)
\(S_{22}\) [\(\mathrm{lb}\)]	\(\phantom{-}9.026 \times 10^4\)	\(\phantom{-}9.027 \times 10^4\)
\(S_{33}\) [\(\mathrm{lb}\)]	\(\phantom{-}3.941 \times 10^4\)	\(\phantom{-}3.943 \times 10^4\)
\(S_{14}\) [\(\mathrm{lb \cdot in}\)]	\(\phantom{-}1.074 \times 10^5\)	\(\phantom{-}1.074 \times 10^5\)
\(S_{25}\) [\(\mathrm{lb \cdot in}\)]	\(-5.201 \times 10^4\)	\(-5.201 \times 10^4\)
\(S_{36}\) [\(\mathrm{lb \cdot in}\)]	\(-5.635 \times 10^4\)	\(-5.635 \times 10^4\)
\(S_{44}\) [\(\mathrm{lb \cdot in^2}\)]	\(\phantom{-}1.679 \times 10^4\)	\(\phantom{-}1.679 \times 10^4\)
\(S_{55}\) [\(\mathrm{lb \cdot in^2}\)]	\(\phantom{-}6.621 \times 10^4\)	\(\phantom{-}6.621 \times 10^4\)
\(S_{66}\) [\(\mathrm{lb \cdot in^2}\)]	\(\phantom{-}1.725 \times 10^5\)	\(\phantom{-}1.725 \times 10^5\)