He closed the book and looked at the worn cover: R. S. Khurmi – Strength of Materials . Underneath, in faded letters: “For B.E., B.Tech., and Competitive Exams.”
Step by step, he followed Khurmi’s method. First, find the reaction. Then the shear force diagram. Then the maximum bending moment at the fixed end. He calculated the moment of inertia for a square section. Then the section modulus. Then stress.
For the first time, Arjun smiled at the book. Khurmi wasn’t just giving formulas—he was teaching engineering judgment. The book was a silent mentor, unforgiving but fair. It never let you guess. It made you derive, verify, and then doubt yourself until you understood. R S Khurmi Strength Of Materials
He redrew his beam. He listed the given data: Length 2 m, load 500 N at free end, cross-section 50x50 mm. He turned to the section on Cantilevers . There it was: Bending stress = (M * y) / I .
Arjun froze. He had assumed a perfect weld. But his actual support had a sharp internal corner—a classic stress raiser. He added the stress concentration factor from Table 14.3. The theoretical stress doubled. Then he applied the factor of safety. The beam would fail at 80% of the rated load. He closed the book and looked at the worn cover: R
“Come on, Khurmi saab,” Arjun whispered, flipping to Chapter 6: Shear Force and Bending Moment Diagrams .
Khurmi listed them like a judge delivering verdicts: Maximum principal stress theory (Rankine). Maximum shear stress theory (Guest’s). Arjun chose the latter for ductile materials. He recalculated. Still failure. Underneath, in faded letters: “For B
And then, in a small note at the bottom of a page—something he’d skipped for months—Khurmi had written in italics: “In practical design, stress concentration at the fixed support often doubles the nominal stress. Always check the joint detail.”