Factor of safety analysis in Solidworks - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Factor of Safety (FoS) Concept

What does a Factor of Safety (FoS) value of 2 mean in a mechanical design?

A The design can handle twice the expected maximum load before failure.

B The design is unsafe and needs to be doubled in size.

C The design will fail at half the expected maximum load.

D The design has no margin for error and is exactly at the failure point.

💡 Hint

Think about safety margin as a multiplier of expected load.

A Factor of Safety of 2 means the design can safely withstand twice the expected maximum load, providing a safety margin.

❓ dax_lod_result

intermediate

Calculating Average Factor of Safety in a Dataset

You have a dataset of parts with their individual Factor of Safety values. Which DAX measure correctly calculates the average Factor of Safety across all parts?

A Average FoS = MAX(Parts[FactorOfSafety]) - MIN(Parts[FactorOfSafety])

B Average FoS = AVERAGE(Parts[FactorOfSafety])

C Average FoS = SUM(Parts[FactorOfSafety]) / COUNTROWS(Parts)

D Average FoS = COUNT(Parts[FactorOfSafety])

💡 Hint

Use the function that directly calculates the mean of a column.

The AVERAGE function calculates the mean value of the FactorOfSafety column, which is the correct way to find the average FoS.

❓ visualization

advanced

Best Visualization for Factor of Safety Distribution

Which visualization best shows the distribution of Factor of Safety values across multiple parts to identify any parts with low safety margins?

A A line chart showing Factor of Safety over time.

B A pie chart showing the percentage of parts in each category of material.

C A histogram showing the count of parts for ranges of Factor of Safety values.

D A scatter plot of part weight versus cost.

💡 Hint

Think about how to show frequency of values in ranges.

A histogram groups Factor of Safety values into ranges and shows how many parts fall into each range, making it easy to spot low safety margins.

🔧 Formula Fix

advanced

Debugging Incorrect Factor of Safety Calculation

A DAX measure intended to calculate the minimum Factor of Safety per material is written as:
MinFoS = MINX(Parts, Parts[FactorOfSafety])
Why does this measure return the same value for all materials instead of the minimum per material?

Solidworks

MinFoS = MINX(Parts, Parts[FactorOfSafety])

A MINX is iterating over the entire Parts table without filtering by material, so it returns the global minimum.

B MINX cannot be used with numeric columns like FactorOfSafety.

C The measure syntax is incorrect; MINX requires a filter expression.

D The Parts table does not contain a FactorOfSafety column.

💡 Hint

Consider how row context and filters affect MINX.

MINX iterates over the entire Parts table without filtering by material, so it returns the overall minimum Factor of Safety, not per material.

🎯 Scenario

expert

Scenario: Prioritizing Parts for Safety Improvement

You have a report showing Factor of Safety for 100 parts. Parts with FoS below 1.5 are critical. You want to create a Power BI dashboard that highlights these critical parts and shows their count by material. Which approach best achieves this?

A Filter the dataset to only parts with FoS above 1.5 and show their count by material.

B Use a measure that sums Factor of Safety values and display it in a pie chart by material.

C Create a table visual showing all parts and manually scan for FoS below 1.5.

D Create a calculated column with a Boolean flag for FoS < 1.5, then use a slicer to filter and a bar chart to count by material.

💡 Hint

Think about how to flag and filter critical parts dynamically.

Creating a calculated column flagging critical parts allows easy filtering and visualization of counts by material, making it clear which parts need attention.

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