Let's break down the first two parts of the problem.

Part a: Find the Component Stresses at Point A

The load applied on the bracket is $95 \, \text{N}$ and is positioned 300 mm from point A. The rod has a diameter of $25 \, \text{mm}$, and there's a hole drilled through it near point A with a diameter of $5 \, \text{mm}$.

The key steps are:

1. Determine the force components: The external force applied is 95 N vertically downwards. Since point A is closer to the fixed support, it will experience both bending and axial stress.

2. Determine axial stress: Axial stress $\sigma_{\text{axial}}$ is given by: $\sigma_{\text{axial}} = \frac{F}{A}$ where:

   • $F = 95 \, \text{N}$ is the applied load.
   • $A = \text{cross-sectional area} = \frac{\pi}{4} (d_{\text{rod}}^2 - d_{\text{hole}}^2)$, where $d_{\text{rod}} = 25 \, \text{mm}$ and $d_{\text{hole}} = 5 \, \text{mm}$.

3. Determine bending stress: The bending stress at point A can be calculated using: $\sigma_{\text{bending}} = \frac{M}{S}$ where:

   • $M = F \times d_{\text{moment arm}} = 95 \, \text{N} \times 300 \, \text{mm}$.
   • $S = \frac{\pi}{32} d_{\text{rod}}^3$, the section modulus of the solid rod with the hole ignored for now.

Part b: Find the Stress Concentration Factors

The hole near point A introduces a stress concentration that amplifies the local stress. The stress concentration factor (Kt) depends on the geometry and loading conditions.

1. Axial stress concentration factor: For a hole in a solid circular shaft under axial tension, the stress concentration factor $K_t$ can be estimated from standard tables or charts depending on the ratio of $d_{\text{hole}} / d_{\text{rod}}$. This ratio is: $\frac{d_{\text{hole}}}{d_{\text{rod}}} = \frac{5 \, \text{mm}}{25 \, \text{mm}} = 0.2$ Using a standard chart for axial loading with a central hole, we can find $K_t$ based on this ratio.

2. Bending stress concentration factor: For a hole in a circular shaft under bending, the stress concentration factor $K_t$ is again determined from charts or equations for bending. The same ratio $d_{\text{hole}} / d_{\text{rod}}$ applies.

I can calculate the exact values for axial and bending stresses and their concentration factors. Let's proceed with the computation!Here are the results for part (a):

• Axial Stress at point A: $\sigma_{\text{axial}} = 0.202 \, \text{MPa}$
• Bending Stress at point A: $\sigma_{\text{bending}} = 18.58 \, \text{MPa}$

For part (b), the ratio of the hole diameter to the rod diameter is $d_{\text{hole}} / d_{\text{rod}} = 0.2$. Using this ratio, we can refer to standard tables or charts for stress concentration factors ($K_t$) for axial and bending loading. Typically, for this ratio:

• The axial stress concentration factor $K_t$ for a hole is around 2.0 to 2.5.
• The bending stress concentration factor $K_t$ is usually higher, ranging from 2.5 to 3.0, due to the more pronounced effect of bending around the hole.

Let me know if you'd like to proceed with finding the factors of safety or if you have questions!

Follow-up questions:

1. How do we derive the section modulus for irregular shapes?
2. What influences the choice of stress concentration factors?
3. Can bending stress be more critical than axial stress in certain designs?
4. What are some common materials with lower stress concentration effects?
5. How do drilled holes affect fatigue life?

Tip:

Always consider the material's yield strength when calculating stresses to ensure the design remains within safe limits.