Simulation Quiz 3

Understanding the Physics of Structural Mechanics - Simulation Quiz 3

Complete the simulation and have all the results ready BEFORE starting the quiz.

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1 / 15

What is the maximum magnitude of deformation in the y-direction under the applied load? Select the BEST option below.

0-15 mm

15-30 mm

30-40 mm

40-50 mm

2 / 15

What is the maximum equivalent stress experienced in the plastic arm? Select the BEST option.

30-40 MPa

10-20 MPa

40-50 MPa

20-30 MPa

3 / 15

Consider the locations A through D in the figure below. Where is the location of the maximum XZ shear stress component?

Location A

Location B

Location D

Location C

4 / 15

Assume that the hinge connecting the arm to the sunglass frame can withstand a total moment of up to 80 N∙mm. Select TWO statements that are correct, based on the analysis results. (Hint: use Moment Reaction probe.)

The reaction moment history shows nonlinear behavior.

The reaction moment history shows linear behavior.

The hinge cannot withstand the applied force of 0.75 N.

The hinge can withstand the applied force of 0.75 N.

5 / 15

Which component of stress contributes most to the equivalent stress? Select the BEST option.

X component (Normal Stress)

YZ component (Shear Stress)

XY component (Shear Stress)

Y component (Normal Stress)

6 / 15

Let’s say that the maximum deformation of the arm is designated as deformation_current. Consider a separate case where the force is doubled on the arm, and the maximum deformation of the arm is called deformation_twice. (Do not run such an analysis.) Assuming that the plastic material still responds in a linear elastic manner, which statement below is correct?

2*deformation_current < deformation_twice

2*deformation_current ≈ deformation_twice

2*deformation_current = deformation_twice

2*deformation_current > deformation_twice

7 / 15

Review the Reaction Force probe and notice that the reaction force history (Force vs Time) is linear. Select the option below that is correct.

The reaction force history is linear because the material is linear elastic.

The reaction force history is linear because the force on the arm is applied in a linear fashion.

The reaction force history shows a linear behavior, so this analysis could also be solved accurately with small deflection theory.

The reaction force history looks linear, but the reaction force is mildly nonlinear with respect to time.

8 / 15

Add a Maximum Shear Stress result object and review the result. What is the value of the Maximum Shear Stress when half of the load is applied? (Do not run such an analysis.) Select the correct option.

Greater than 7.5 MPa but less than 8.5 MPa

Greater than 5.5 MPa but less than 6.5 MPa

Greater than 4.5 MPa but less than 5.5 MPa

Greater than 6.5 MPa but less than 7.5 MPa

9 / 15

Examine the Total Deformation result. Based on the result history, how would the result compare if your ran with Large Deflection effects turned off? (Do not run such an analysis.) Select the best option below.

Total Deformation with Large Deflection effects turned off will be the same.

Total Deformation with Large Deflection effects turned off will have a very different

Total Deformation with Large Deflection effects turned off will be lower.

Total Deformation with Large Deflection effects turned off will be higher.

10 / 15

Consider the intermediate result at “Time = 0.1 [s]”. Select the correct statement below.

The result at Time=0.1 seconds is not a valid result since force equilibrium has not been satisfied yet.

The result at Time=0.1 seconds show the results when 10% of the final load has been applied.

The result at Time=0.1 seconds is a linear analysis result.

The result at Time=0.1 seconds is valid only in a transient analysis.

11 / 15

What is the maximum deformation of the sunglass arm under the applied load? Select the BEST option.

125-175 mm

225-275 mm

175-225 mm

75-125 mm

12 / 15

Consider the same model with the same loads and boundary conditions, but the arm is made of a stiffer plastic (higher elastic modulus). (Do not run such an analysis.)

Select two correct statements below.

With a stiffer plastic, the total reaction moment at the base would be greater under the same applied load

With a stiffer plastic, the total deformation would be less under the same applied load

With a stiffer plastic, the total reaction moment at the base would be less under the same applied load

With a stiffer plastic, the total deformation would be higher under the same applied load

13 / 15

Assume that this plastic will crack if the maximum principal stress exceeds 20 MPa. Select the two correct statements.

The plastic arm will develop cracks under the applied force.

The location of highest maximum principal stress is at the base

The location of highest maximum principal stress is at the tip of the arm, where the force is applied.

The plastic arm will not develop cracks under the applied force.

14 / 15

Carefully review the model and Reaction Force probe results at the Fixed Support. Why is the reaction force in the x-direction at “Base” not equal to 0.75 N (within a tolerance of 0.1%)?

The normal direction of the surface of the arm “Pull” is not exactly parallel to the global x-axis causing the x-direction reaction force not to equal to 0.75 N, but the total reaction force is the same as the applied force.

Finite numerical precision of computers prevents the x-reaction force to equal the applied force.

The material absorbs some energy, so the reaction force does not equal the applied force.

The analysis is nonlinear, so it is expected that the direction of the reaction force changes.

15 / 15

Why are Large Deflection effects used in this simulation? Select the BEST option.

The model has high stresses, which require large deflection effects.

The model experiences large deformation.

This analysis shows linear results, so Large Deflection effects are actually not needed to get accurate results

The model utilizes a nonlinear material model.

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Physics of Structural Mechanics

Sunglass Arm

Total Available Time - 45 mins

Total Number of Questions - 15