고체역학 (Beer) — Pure Bending: Problem 4.140

4.140 The couple M acts in a vertical plane and is applied to a beam oriented as shown. Determine (a) the angle that the neutral axis forms with the horizontal, (b) the maximum tensile stress in the beam. Given for Fig. P4.140: - Applied moment: \( M = 750 \text{ N}\cdot\text{m} \) - Cross-section: Isosceles triangle with base \( b = 25 \text{ mm} + 25 \text{ mm} = 50 \text{ mm} \) and height \( h = 90 \text{ mm} \). - Orientation: The symmetry axis of the triangle is tilted \( 20^\circ \) to the left of the vertical plane. - Dimensions: Altitude is \( 90 \text{ mm} \), base width is \( 50 \text{ mm} \), and the centroid \( C \) is located \( 30 \text{ mm} \) from the base.