📍 Location: Kalpakkam
📅 Date: 10th June 2025
🔧 1. Structural Mechanics & Machine Design
Q1. Why is an I-section (I-beam) widely used in engineering applications?
Key Concepts to Cover:
- High moment of inertia about the bending axis ⇒ greater bending strength
- Material is concentrated away from the neutral axis
- Optimized for bending loads, while saving material and weight
- Used in bridges, building structures, cranes, etc.
Q2. A tank is mounted on an overhead platform and connected to a tap.
a. How would you calculate the time to drain it completely?
b. Which equation applies?
Answer:
- Use Bernoulli’s equation combined with Torricelli’s law: v=2ghv = \sqrt{2gh}v=2gh
- Then integrate the flow rate to get total time depending on tank shape.
🚆 2. Mechanics of Rolling Stock (Rail Transport)
Q3. Why are railway wheels conical instead of cylindrical?
Key Points:
- Conical shape allows for self-centering
- Helps manage different turning radii of inner and outer wheels on curves
- Minimizes wear and lateral movement
- Ensures stability and smoother ride
🧪 3. Material Science & Strength Testing
Q4. What is Impact Strength?
- The ability of a material to resist shock loading or sudden force
- Measured using Charpy or Izod impact test setups
- Indicates toughness under high strain rate
Q5. What is a Brake? How does it work in practical applications?
- Device used to slow or stop motion using frictional force
- Types:
- Mechanical Brakes (Drum, Disc)
- Hydraulic Brakes
- Electromagnetic or Pneumatic Brakes
- Converts kinetic energy into heat energy
🧱 4. Solid Mechanics – Stress & Strain
Q6. Define Stress and Strain. Illustrate with a diagram.
- Stress (σ): Force per unit area (Tensile, Compressive, Shear)
- Strain (ε): Deformation per unit length
- Use stress-strain curves to explain material behavior
Q7. Under hydrostatic loading, how do you calculate strain in the X-direction?
- Use Generalized Hooke’s Law: εx=1E[σx−ν(σy+σz)]\varepsilon_x = \frac{1}{E}[\sigma_x – \nu(\sigma_y + \sigma_z)]εx=E1[σx−ν(σy+σz)]
- For hydrostatic stress, all normal stresses are equal.
🧰 5. Mechanical Systems & Lifting Devices
Q8. What are the different types of Overhauling in lifting systems?
- Overhauling: When the load tends to move downward on its own
- Systems:
- Screw Jacks
- Hoists
- Types:
- Self-locking Screws (no movement without external torque)
- Overhauling Screws (load moves unless restrained)
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