# Theory Quiz

Note: The Expected Completion Time for this quiz is 60 mins but, the Maximum Available Time to complete the quiz is 90 mins.

#### Total Number of Questions - 45

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Methods of Solving Problems in Structural Mechanics - Theory Quiz

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1 / 45

In a dynamic analysis using the mode superposition method, the displacement can be expressed as _____. Select the best option.

2 / 45

Bending of a fishing rod shows non-linear behavior because _____. Select the best option.

3 / 45

When the excitation frequency is equal to the natural frequency and the damping is zero, the modal coordinate value is _____.

4 / 45

An engineer redesigns a part with material removed from the part in the new design. Which of the following statements holds? Select the three best options.

5 / 45

Which expression represents the harmonic equation of motion in modal form?

6 / 45

A structure that experiences _____ for a given load can still support that load without catastrophic failure. Select the best option to complete the sentence.

7 / 45

Which of these are correct statements about time intgeration methods? Select the two best options.

8 / 45

To solve a nonlinear dynamic problem, which of the following statements are correct about implicit and explicit time integration methods? Select the two best options.

9 / 45

Which of the following is a method used for solving non-linear response of structure? Select the best option.

10 / 45

In a harmonic steady state response with more than one excitation, which variable dictates the relative timing of the excitations.

11 / 45

A structure is deemed unstable when _____. Select the best option to complete the sentence.

12 / 45

Which of these statements is NOT true about buckling? Select the option that is false.

13 / 45

Exciting a physical system at the natural frequency can occur, _____. Select the two best options.

14 / 45

A large electric motor that drives a system of pulleys in a factory environment experiences excessive vibration while it is slowly being brought up to operating speed. A Harmonic Analysis of the application shows an amplitude vs frequency plot that proves that the motor is passing thru two natural frequencies during this start up. Assuming the operating speeds cannot be altered, choose the two best options for improving the design.

15 / 45

From the force-displacement curve of an unstable structure in a static analysis, how can one identify the point of instability? Select the best option.

16 / 45

The "d" parameter in the Mooney-Rivlin Strain Energy expression $\Psi =C_{10}(I_{1}-3)+C_{01}(I_{2}-3)+\frac{1}{d}(J-1)^2$ is inversely proportional to _____.

17 / 45

For a fully incompressible hyperelastic material, the strain energy function is usually expressed _____. Select the best option.

18 / 45

The mode superposition method is _____. Select the best option.

19 / 45

The tolerance defined by a user for the Newton Raphson method is called _____.

20 / 45

What are the benefits to treating some parts as a rigid body in a large assembly? Select the two best options.

21 / 45

Which is the best reason for using more terms in a hyperelastic model? Select the best option.

22 / 45

Engine vibration mounts serve to _____. Select the best option.

23 / 45

To maintain numerical stability while using the explicit time integration method, the time-step size should satisfy the CFL condition, which is $\Delta t \leq f \left ( \frac{h}{c} \right )$. Which of the following statements are correct about the CFL condition? Select the two best options.

24 / 45

When considering eigenvalue buckling analysis, why is the point on force-displacement curve at which a structure undergoes buckling called a bifurcation point? Select the best option.

25 / 45

Which of the following statements is relevant to using a full method in a harmonic analysis? Select the best option.

26 / 45

In reality how many iterations are needed for sum of internal forces to be exactly equal to the applied forces for a nonlinear problem? Select the best option.

27 / 45

Local buckling due to weight is noticed along a section of the wall of a large, axisymmetric oil storage tank. You are asked to reproduce the buckling scenario via finite element simulation. Among the options listed, which type of analysis would be best for completing this task?

28 / 45

Stress developed in a hyperelastic material is calculated from _____. Select the best option.

29 / 45

While simulating the drop test of a circuit board on to a hard ground using an explicit analysis, if the computing time is very long, which of the following options may help reduce the computational time? Select the three best options.

30 / 45

Force convergence failure for a Newton Raphson method indicates _____. Select the best option.

31 / 45

Which of the following holds true for a cantilever (such as a diving board) excited by a harmonic external force with its frequency matching the second natural frequency? Select the best option.

32 / 45

Once a ductile metal under a structural load exceeds the elastic limit, it immediately _____. Select the best option.

33 / 45

Which of the following statements are correct about the stability of the time integration method in finite element methods? Select the two best options.

34 / 45

What is the relationship between displacement, velocity, and acceleration for a dynamic problem? Select the three best options.

35 / 45

Which term describes the area under the stress-strain curve in a unit volume of hyperelastic material? Select the best option.

36 / 45

An analyst solves a simple small problem using the full method and the mode superposition method. Which one of the following statements is correct? Select the best option.

37 / 45

Dynamic instabilities occur due to _____. Select the best option to complete the sentence.

38 / 45

In the hyperelastic strain energy equations, as the parameter d (which is inversely proportional to the initial bulk modulus) decreases, the material tends to become _____. Select the best option.

39 / 45

Most ductile metals under a structural load undergo elastic deformation for strain ranges up to _____. Select the best option.

40 / 45

Which of the following is correct for running an Ansys Simulation? Select the best option.

41 / 45

Structural instabilities may occur due to different reasons, but two common ones are due to a loss of stiffness and due to inertial effects. Dynamic instability describes the latter situation. Which of these cases is NOT a dynamic instability?

42 / 45

Two analysts solve the same dynamic analysis of a large model. One of them changes the solution method to mode superposition (with no other differences in the analysis). The analysts find that there is a significant time difference between them to solve the models. Which of the following statements is correct in regards to his scenario? Select the best option.

43 / 45

The displacement vector for a mode superposition solution with three modes is to be computed. The modal coordinate for each mode 1, 2 and 3 is 1 and for each of these modes, let's assume the value from the mode shape vector for a single node of interest is also 1. What will be the value of the nodal displacement calculated for this node of interest using these three modes?

44 / 45

For a response spectrum analysis, the mode superposition method is _____. Select the best option.

45 / 45

The velocity derived from the complex displacement function is characterized by which expression?