(Solved): \( 18.27 \) (A) (SI units) An L-shaped structural section is direct extruded from an aluminum alloy ...

\( 18.27 \) (A) (SI units) An L-shaped structural section is direct extruded from an aluminum alloy billet whose length \( =500 \) \( \mathrm{mm} \) and diameter \( =100 \mathrm{~mm} \). Dimensions of the extruded cross section are given in Figure P18.27. The strength coefficient and strain-hardening exponent of the aluminum alloy are \( 240 \mathrm{MPa} \) and \( 0.15 \), respectively (Table 3.4). The die angle \( =90^{\circ} \), and the Johnson strain equation has constants \( a=0.8 \) and \( b=1.5 \). Determine the (a) extrusion ratio, (b) shape factor, and (c) length of the extruded section if the butt remaining in the container at the end of the ram stroke is 25 mm long. (d) Compute the maximum force required to drive the ram forward at the start of extrusion. Figure P18.27 Part for Problem \( 18.27 \) (dimensions are in \( \mathrm{mm} \) ).