Factor of safety analysis in Solidworks - Real Business Scenario

Scenario Mode

👤 Your Role: You are a mechanical engineer working with SolidWorks Simulation

📋 Request: Your manager wants you to analyze the factor of safety for a new bracket design under expected load conditions to ensure it is safe for use.

📊 Data: You have the 3D model of the bracket, material properties including yield strength, and the expected load forces applied at specific points.

🎯 Deliverable: A report showing the factor of safety distribution on the bracket with a clear visualization and summary of minimum factor of safety.

Sample Data

Load Point	Force (N)	Material Yield Strength (MPa)	Max Stress at Load Point (MPa)
Point A	500	250	120
Point B	300	250	90
Point C	400	250	110
Point D	200	250	70

1

Step 1: Open the bracket 3D model in SolidWorks Simulation and apply the given load forces at the specified points.

Apply 500N at Point A, 300N at Point B, 400N at Point C, and 200N at Point D as external forces.

Expected Result

Loads correctly applied to the model at specified points.

2

Step 2: Assign the material properties to the bracket model, ensuring the yield strength is set to 250 MPa.

Set material yield strength = 250 MPa in the material properties panel.

Expected Result

Material properties updated with yield strength of 250 MPa.

3

Step 3: Run the static simulation to calculate the stress distribution on the bracket under the applied loads.

Run static study and solve for stress results.

Expected Result

Simulation completes with stress results showing max stress values at load points.

4

Step 4: Calculate the factor of safety (FoS) at each load point using the formula: FoS = Material Yield Strength / Max Stress.

FoS at Point A = 250 / 120 = 2.08 FoS at Point B = 250 / 90 = 2.78 FoS at Point C = 250 / 110 = 2.27 FoS at Point D = 250 / 70 = 3.57

Expected Result

Factor of safety values calculated for all load points.

5

Step 5: Create a color-coded factor of safety plot on the bracket model to visualize areas with low and high safety factors.

Use SolidWorks Simulation's factor of safety plot feature with a color gradient from red (low FoS) to green (high FoS).

Expected Result

Visual factor of safety plot displayed on the bracket showing safety distribution.

6

Step 6: Generate a summary report including the minimum factor of safety and recommendations.

Minimum FoS = 2.08 at Point A, which is above the typical safety threshold of 1.5, so design is safe.

Expected Result

Report created with factor of safety summary and confirmation that bracket design is safe.

Final Result

Bracket Factor of Safety Report
--------------------------------
Load Point | Max Stress (MPa) | FoS
--------------------------------
Point A   | 120              | 2.08
Point B   | 90               | 2.78
Point C   | 110              | 2.27
Point D   | 70               | 3.57

Minimum Factor of Safety: 2.08 (Point A)

Status: Design is safe for use under given loads.

[Color-coded FoS plot shows red near Point A, green elsewhere]

✓The minimum factor of safety is 2.08 at Point A, which is above the safety threshold of 1.5.

✓All other points have higher factors of safety, indicating the bracket is well designed.

✓The color-coded plot highlights the critical area near Point A for focused inspection.

Bonus Challenge

Perform a sensitivity analysis by varying the load at Point A from 400N to 600N in increments of 50N and observe how the factor of safety changes.

Show Hint

Adjust the load force at Point A in the simulation setup and rerun the analysis for each increment, then record the minimum factor of safety.

Practice

1. What does the factor of safety (FoS) represent in SolidWorks analysis?

easy

A. The speed at which the simulation runs

B. The total weight of the model

C. The ratio of material strength to the maximum expected stress

D. The number of parts in the assembly

Solution

1. Step 1: Understand the definition of factor of safety

   The factor of safety is a measure comparing how strong a material is versus the stress it will face.

2. Step 2: Relate factor of safety to design safety

   A higher factor of safety means the design is safer because the material can handle more stress than expected.

3. Final Answer:

   The ratio of material strength to the maximum expected stress -> Option C

4. Quick Check:

   FoS = Strength / Stress [OK]

Hint: Remember FoS = strength divided by stress [OK]

Common Mistakes:

• Confusing FoS with weight or speed
• Thinking FoS is the number of parts
• Ignoring the stress in calculation

2. Which of the following is the correct way to interpret a factor of safety value of 1.5 in SolidWorks simulation?

easy

A. The model has 1.5 parts

B. The material can withstand 1.5 times the expected stress

C. The simulation ran 1.5 times faster

D. The material will fail at 1.5 units of stress

Solution

1. Step 1: Understand what a factor of safety value means

   A factor of safety of 1.5 means the material strength is 1.5 times greater than the stress it will experience.

2. Step 2: Interpret the value in context

   This means the design is safe up to 1.5 times the expected load before failure.

3. Final Answer:

   The material can withstand 1.5 times the expected stress -> Option B

4. Quick Check:

   FoS = 1.5 means 1.5x strength [OK]

Hint: FoS > 1 means material stronger than stress [OK]

Common Mistakes:

• Thinking FoS is a stress value
• Confusing speed or parts with FoS
• Assuming FoS less than 1 is safe

3. Given a material strength of 300 MPa and a maximum stress from simulation of 150 MPa, what is the factor of safety?

medium

A. 2

B. 0.5

C. 450

D. 150

Solution

1. Step 1: Identify the formula for factor of safety

   Factor of safety = Material strength / Maximum stress.

2. Step 2: Calculate using given values

   FoS = 300 MPa / 150 MPa = 2.

3. Final Answer:

   2 -> Option A

4. Quick Check:

   300 / 150 = 2 [OK]

Hint: Divide strength by stress to get FoS [OK]

Common Mistakes:

• Multiplying instead of dividing
• Using stress divided by strength
• Confusing units or values

4. A SolidWorks simulation shows a factor of safety less than 1 for a part. What is the most likely cause?

medium

A. Material strength is less than the applied stress

B. Simulation ran too quickly

C. The part has too many features

D. The model is missing a material assignment

Solution

1. Step 1: Understand what FoS less than 1 means

   A factor of safety less than 1 means the stress exceeds the material strength, indicating failure risk.

2. Step 2: Identify the cause from options

   Material strength being less than applied stress directly causes FoS < 1.

3. Final Answer:

   Material strength is less than the applied stress -> Option A

4. Quick Check:

   FoS < 1 means stress > strength [OK]

Hint: FoS < 1 means unsafe: stress > strength [OK]

Common Mistakes:

• Blaming simulation speed
• Thinking number of features affects FoS
• Ignoring material assignment impact

5. You have a part with a factor of safety of 0.8 under current load. To improve safety, you can either increase material strength or reduce load. If increasing strength by 25% is not possible, by what percentage must you reduce the load to achieve a factor of safety of 1.2?

hard

A. 40%

B. 50%

C. 20%

D. 33.3%

Solution

1. Step 1: Understand the relationship between FoS, strength, and load

   FoS = Strength / Load. Strength is fixed, so reducing load increases FoS.

2. Step 2: Calculate required load reduction

   Current FoS = 0.8 = Strength / Load. So Load = Strength / 0.8.
   Desired FoS = 1.2 = Strength / New Load.
   New Load = Strength / 1.2.
   Percentage reduction = ((Old Load - New Load) / Old Load) * 100 = ((Strength/0.8 - Strength/1.2) / (Strength/0.8)) * 100 = ((1/0.8 - 1/1.2) / (1/0.8)) * 100 = ((1.25 - 0.8333) / 1.25) * 100 = (0.4167 / 1.25) * 100 = 33.33%.

3. Final Answer:

   33.3% -> Option D

4. Quick Check:

   Reduce load by 33.3% to raise FoS to 1.2 [OK]

Hint: Use FoS = strength/load and solve for load reduction [OK]

Common Mistakes:

• Trying to increase strength when not allowed
• Calculating percentage incorrectly
• Mixing up load and strength in formula