Question

E 12.9 Sandwich panels. An aircraft quality sandwich panel has the characteristics listed in the table. (a) Use the data and equations 12.30, 12.31 and 12.32 of the text to calculate the equivalent density, flexural modulus and strength. (b) Plot these on a copy of a Modulus - Density, a Strength - Density and Modulus - Strength chart (Figures 3.3, 3.4 and 3.5). Do the flexural properties of the panel lie in a region of property space not filled by monolithic materials?

Answer 1

Ca) THE EQUIVALENT DENSITY Is- 2.65 leg/m 10 x10-3 m lm 265 CALCULATE THE FLEXURAL MODULUS, E = 12 EI %3D bd3 = 12 (67 N. m² ) (51x10-3m)(10 x 10-3 m)³ 15.8 GPa = 15.8 x1o9 Pa CALCULATE THE STRENGTH. 4 Mf bd2 4 (160 N. m ) (51x10-3 m)(10x10-³m)* E 125. 5 x1o6 Pa 125. 5 MPa (b) FROM THE FIGURE, YES, THE FLEXURAL PROPERTIES OF THE PANEL LIE IN AN AREA OF PROPERTY SPACE NOT OCCUUPIED BY MONDLITHIC MATERIALS.