Foundations in Stress Analysis using Ansys Mechanical - Theory Quiz - Ansys Certifications

Foundations in Stress Analysis using Ansys Mechanical - Theory Quiz

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1 / 45

Why is cork but not rubber typically used for the material of a wine bottle stopper? Select the 2 best answers

Rubber has a Poisson's ratio close to zero

Cork is compressible

Rubber is compressible

Cork has a Poisson's ratio close to zero

2 / 45

Which two statements are true for cases involving free thermal expansion?

Developed stresses are proportional to the temperature change

No thermal strain is generated

The material can deform without generating any stress

No elastic strain is generated

3 / 45

Volumetric expansion occurs when all shear strain components are zero and all normal strain components are equal to each other (i.e., $e_{xy}=e_{xz}=e_{yz}=0$ but $e_{xx}=e_{yy}=e_{zz}$). Select the correct statement.

Equivalent strain cannot be determinned without additional information regarding the deformation.

Equivalent strain will be equal to twice the normal strain.

Equivalent strain will be equal to the normal strain.

Equivalent strain is zero when there is only volumetric expansion.

4 / 45

Which statement is true about a stress tensor? Choose two best options.

Stress tensor is not absolute. Under different coordinate systems, its values will be different. However, they all represent the same stress state.

A stress tessor is symmetric along the diagonal.

Under different coordinate systems, the components of a stress tensor remain the same values.

Stress tensor under different coordinate systems represents different stress states.

5 / 45

The constitutive model is a mathematical relationship between _____. Select the best option to complete the sentence.

stress and pressure

stress and force

stress and strain

stress and deformation

6 / 45

There are two cases of principal stresses: case 1 has $s_1$ = 20 MPa, $s_2$ = 0, $s_3$ = 0 while case 2 has $s_1$ = 40 MPa, $s_2$ = 40 MPa, $s_3$ = 20 MPa. Which of the following statements are correct? Choose two best options.

The equivalent stress calculated from case 2 is the larger than the one calculated from case 1.

These three stress states are on the different cylindrical surfaces in principal stress space.

The equivalent stress calculated from case 1 is the same as the one calculated from case 2.

These two stress states are on the same cylindrical surface in principal stress space.

7 / 45

Consider a situation where there are two geometrically identical brackets, each made with a different grade of plastic that have different elastic moduli (stiffness). Both brackets are constrained and loaded in the same manner. Select two statements which are true, assuming linear response.

The location of maximum strain will be the same on both brackets.

The location of maximum deformation will be the same on both brackets.

The location of maximum deformation of either bracket will depend on their elastic modulus (stiffness) value.

The magnitude of maximum strain will be the same for both brackets.

8 / 45

Plasticity is volume preserving. Based on this statement, which measure of strain is associated with plasticity? Select the best option.

Only normal strains

Only shear strains

Volumetric strain

Deviatoric strain

9 / 45

Consider a specimen made of rubber, fixed on one end with a tensile force applied at the other end. Compare this to the same geometry made of steel under the same loading condition. Why does the rubber structure specimen deform more than the steel specimen under the same loading conditions? Select the 2 best options.

Synthetic materials are always stiffer than natural materials

Rubber stretches more compared to steel before it can support the same amount of force

Rubber has a smaller resistance to deformation compared to steel

Rubber has a lower mass density compared to steel

10 / 45

What is the internal force on a particle of a body? Choose the best option.

The internal force is the air pressure on the blade.

The force exerted from its neighboring particles.

The internal force is not present.

The force created by the particle itself.

11 / 45

Poisson's ratio _____. Select the 2 best options that complete the sentence.

has a value between 0.0 and 0.5 for most materials

measures the amount of shear strain experienced

is also known as the material's elastic limit

measures the amount of strain in directions perpendicular to the loading direction

12 / 45

Which of the following are examples of thermal expansion? Choose 2 best options.

Failure of bolts on the centrifugal pump experiencing severe vibrations

Buckling of railway tracks in hot summer

Condensation appearing on a glass window during a cold night

Using mercury thermometer to measure body temperature

13 / 45

Hooke's Law states that _____. Select the 2 best answers that complete the statement.

deformation is linear

stresses developed in a part are directly proportional to the strains

stresses developed in a part are inversely proportional to the strains

deformation is nonlinear

14 / 45

If the body is constrained to prevent free thermal expansion, then _____. Select the best option that completes the sentence.

there are no stresses in the body

there is no thermal strain in the body

there is no elastic strain in the body

non-zero elastic and thermal strains will develop

15 / 45

A slender bar is fixed at both its ends. It is then heated such that its temperature increases uniformly by $\Delta T$. This produces a thermal strain $x$ in the axial direction. What is the elastic strain produced in the bar in the axial direction?

$x/\Delta T$

$-x/\Delta T$

$-x$

$x$

16 / 45

Which of the following statements are correct for stress in solid mechanics? Choose two best options.

Stress results can be used to determine if a material reaches its strength limit.

Stress over a body can be calculated by dividing the applied external force by the area under the force.

Stress is a measure of force transmission to the interior of continuous bodies.

Stress is linearly proportional to mechanical strain.

17 / 45

Which of the following is a correct definition of 1D true strain?

True Strain = $ln(l/l_0)$

True Strain = 1+Engineering Strain

True Strain = $1-(\Delta l/l_0)$

True Strain = ${(l_0+\Delta l)/l_0} - 1$

18 / 45

How many normal stress components are in a stress tensor? Choose the best option.

1

3

6

9

19 / 45

Consider a one-dimensional bar with one end fixed while the other end has been extended by a displacement of $u_{0}$. The length of the bar = $L$. The one-dimensional stiffness of the material is $E$. If the strain over the bar is $u_{0}/L$, what is the stress over the bar? Choose the best option.

$Eu_{0}/L$

$Eu_{0}$

$\frac{Eu_{0}}{L/2}$

$Eu_{0}L$

20 / 45

Select the best option to complete the statement.

The linear elastic constitutive model is _____.

used to represent the response of most metals under small strains

is governed by Newton's law

used to represent the response of most non-metals under large strains

complex

21 / 45

What causes deformation of a structure? Choose 2 best options.

Loading, such as forces or gravity

Surface finishes of mating components

Insufficient torque applied to bolted connections

Thermal strain caused by temperature changes

22 / 45

What does the coefficient of thermal expansion describe?

How much heat flux is transmitted through a material due to unit temperature gradient

How the stresses are generated in the object due to thermal condition

How much heat flux is needed to cause a unit difference in temperature between solid and fluid

How much strain is generated with change in temperature

23 / 45

Which of the following statements are true about compressible materials? Choose the two best options.

They can change their volume

They can change their shape

They do not change their volume

They never change their shape

24 / 45

Hydrostatic pressure is equal to _____. Select the best option.

The largest shear stress component

The average of the three principal stresses acting on a body

The largest normal stress component

Twice the equivalent stress

25 / 45

Select the three statements that are correct regarding deformation.

Deformation is simply calculated by subtracting the original configuration from the current configuration

Deformation may include rigid-body motion

Deformation may include distortion

Deformation may be measured in different ways, so care must be taken in interpreting deformation results.

26 / 45

Which of the following cases can be studied with solid mechanics? Choose the best two options.

Predicting airflow around airplane that produces lift

Simulating the movement of atoms when a subject is heated up

Studying the expansion of a steel joint under high temperature

Calculating vibration of wings of airplane under wind load

27 / 45

A body with volume V and density d is immersed in water at depth h. It has pressure p acting uniformly in all directions. What is the value of the hydrostatic stress in the body?

p/3

hV

Vdp

p

28 / 45

Consider a case with a block of steel and a block of aluminum, neglecting the effect of gravity and assuming linear elastic material response. The two blocks rest on a hard ground and have the same compressive force applied on top. The block of aluminum has _____. Select the 2 best options that complete the sentence for this scenario.

less deformation than the steel block

less resistance to deformation than the steel block

more resistance to deformation than the steel block

more deformation than the steel block

29 / 45

The measure of how resistant a material is to undergo volumetric strain is called _____. Select the best option.

tangent stiffness modulus

Young's modulus

bulk modulus

shear modulus

30 / 45

Which of the following statements is true about strain? Select the best option.

Strain measures the increase in force

Strain measures the amount of distortion

Strain measures rigid body motion

Strain is the original dimensions of the part before it deforms

31 / 45

What is the definition of stress component $\sigma_{xy}$? Choose the best option.

Stress on the normal face of x that points in x direction.

Stress on the normal face of y that points in y direction.

Stress on the normal face of y that points in x direction.

Stress on the normal face of x that points in y direction.

32 / 45

In a uniaxial stress-strain test, necking is generally observed before failure for which type of material? Select the best option.

Ceramics

Ductile metals

Glass

Concrete

33 / 45

Which of the following equations defines 1D engineering strain?

$\epsilon=\Delta l/l_{o}$

$\epsilon=\int \frac{\mathrm{d} l}{l}$

$\epsilon _{ij}=\frac{1}{2}\left ( u_{i,j} + u_{j,i}\right )$

$\sigma =E\epsilon $

34 / 45

A material which deforms such that it changes its shape but does not change its volume is _____. Select the best option to complete the sentence.

a stiff material

a compressible material

an incompressible material

a soft material

35 / 45

Which equation correctly represents total Strain $\varepsilon ^{Tot}$, where $\varepsilon ^{e}$ = Elastic strain and $\varepsilon ^{th}$ = Thermal Strain ?

$\varepsilon ^{Tot}=\frac{\varepsilon ^{e}}{\varepsilon ^{th}}$

$\varepsilon ^{Tot}=\varepsilon ^{e}\varepsilon ^{th}$

$\varepsilon ^{th}=\varepsilon ^{Tot}+\varepsilon ^{e}$

$\varepsilon ^{Tot}=\varepsilon ^{e}+\varepsilon ^{th}$

36 / 45

Which of the following analysis types are done on frequency domain? Choose two best options.

Rigid-body analysis

Modal analysis

Harmonic analysis

Static analysis

37 / 45

Cork has a Poisson's ratio of 0.0. This means that cork is _____. Select the best option to complete the statement.

highly compressible

nearly incompressible

very ductile

very brittle

38 / 45

Which tensor form is correct for thermal strain?

$\begin{bmatrix} \varepsilon^{th}_{xx} & -\varepsilon^{th}_{xy} & -\varepsilon^{th}_{xz}\\ \varepsilon^{th}_{yx} & \varepsilon^{th}_{yy} & -\varepsilon^{th}_{yz}\\ \varepsilon^{th}_{zx} & \varepsilon^{th}_{zy} & \varepsilon^{th}_{zz} \end{bmatrix}$

$\begin{bmatrix} \varepsilon^{th}_{xx} & 0 & 0\\ 0 & \varepsilon^{th}_{yy} & 0\\ 0 & 0 & \varepsilon^{th}_{zz} \end{bmatrix}$

$\begin{bmatrix} \varepsilon^{th}_{xx} & -1 & -1\\ 1 & \varepsilon^{th}_{yy} & -1\\ 1 & 1 & \varepsilon^{th}_{zz} \end{bmatrix}$

$\begin{bmatrix} \varepsilon^{th}_{xx} & \varepsilon^{th}_{xy} & \varepsilon^{th}_{xz}\\ \varepsilon^{th}_{yx} & \varepsilon^{th}_{yy} & \varepsilon^{th}_{yz}\\ \varepsilon^{th}_{zx} & \varepsilon^{th}_{zy} & \varepsilon^{th}_{zz} \end{bmatrix}$

39 / 45

The reverse design process relies on topology optimization technology and can help an engineer determine the best shape of the structure for a given set of conditions. Which of the following statements are correct for the reverse design process? Choose two best options.

Topology optimization creates geometry from scratch.

Appropriate boundary conditions and load conditions are needed for the reverse design process.

Topology optimization usually leads to irregular geometry which may be challenging to manufacture.

Finite element method is not needed in reverse engineering.

40 / 45

Select the three best options that are needed to prepare an engineering problem for simulation.

Isolate a single part from an assembly to analyze

Decide what kind of material model should be used and obtain proper material parameters

Select appropriate loads and boundary conditions to represent the real-life situation

Determine the necessary geometric details to include in the model

41 / 45

How many independent components of shear stresses are in a stress tensor?

1

3

6

9

42 / 45

If von Mises stress is zero, which statement is true? Choose the best option.

All principal stresses have the same value.

Two principal stresses are zero.

Von Mises stress cannot be zero.

One principal stress value is zero.

43 / 45

Consider a simulation of a steel beam of an office building where the maximum load capacity needs to be determined. What is the appropriate analysis type? Choose the best option.

Time- history dynamics analysis

Static analysis

Modal analysis

Harmonic analysis

44 / 45

Which results can be obtained from mechanical simulations of flexible bodies under applied loads? Choose three correct options.

Stresses and strains

Intermolecular forces

Deformations

Reaction forces

45 / 45

If the max stress at any location on a bike frame exceeds the yield strength of the material, the bike frame will _____. Select the best option to complete the sentence.

collapse due to fatigue of the material

collapse due to plastic deformation

redistribute loads to maintain its stiffness

undergo plastic deformation at that location

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Private: Foundations in Stress Analysis using Ansys Mechanical

Foundations in Stress Analysis using Ansys Mechanical - Theory Quiz

Total Available Time - 90 mins

Total Number of Questions - 45

Foundations in Stress Analysis using Ansys Mechanical - Theory Quiz