Question

6.1 A simply supported laminated composite beam (Figure 6.6) made of glass/epoxy is 75 mm long and has the layup of [±30]2s. A uniform load is applied on the beam that is 5 mm in width. Assume each ply is 0.125 mm thick and the properties of glass/epoxy are from Table 2.1.

1. What is the maximum deflection of the beam?

2. Find the local stresses at the top of the laminate.

q- 100 N/m 0.075 m FIGURE 6.6 Uniformly loaded simply supported beam. TABLE 2.1 Typical Mechanical Properties of a Unidirectional Lamina (SI System of Units) Glass Boron Graphitel Property Symbol epoxy epoxy epoxy Fiber volume fraction Longitudinal elastic modulus Transverse elastic modulus Major Poisson's ratio Shear modulus Ultimate longitudinal tensile strength Ultimate longitudinal compressive strength Ultimate transverse tensile strength Ultimate transverse compressive strength Ultimate in-plane shear strength Longitudinal coefficient of 0.45 38.6 0.50 0.70 181 E! E GPa GPa 204 8.27 0.26 4.14 18.50 0.23 5.59 10.30 0.28 7.17 GPa MPa 1062 610 31 1500 1500 40 (σ 1)ult 1260 (Oi)lMPa 61 (o2MPa 202 (T12)tMPa 72 um/m/°C um/m/°C m/m/kg/kg m/m/kg/kg 8.6 0.02 thermal expansion thermal expansion moisture expansion Transverse coefficient of 22.1 30.3 22.5 Longitudinal coefficient of β1 0.00 0.00 0.00 Transverse coefficient of 0.60 0.60 0.60 moisture expansion Source: Tsai, S.W. and Hahn, H.T., Introduction to Composite Materials, CRC Press, Boca Raton, FL, Table 1.7, p. 19; Table 7.1, p. 292; Table 8.3, p. 344. Reprinted with permission.

Answer 1

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(2) Local stress at-Hu top of--HL Laminate- 工 8.138 X10-13 my Mid Spam アM-0.0+0.3 Nm of the Beam (G) 1. 0.070 3 (0.125%103 x 8 138 10 67こー5.319 M Pa ere ve Sign impliet that the tA