fem Flashcards

1
Q

Which factor is not typically considered when assessing the quality of a finite element mesh?
a) Element aspect ratio
b) Skewness of elements
c) Number of elements in the mesh
d) Smoothness of element boundaries

A

c) Number of elements in the mesh

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2
Q

In Finite Element Method, what purpose do boundary conditions serve?
a) To specify the material properties of the elements
b) To apply loads to the structure
c) To model external environmental effects
d) To restrict the displacements at certain locations

A

d) To restrict the displacements at certain locations

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3
Q

In the Finite Element Method, how are material properties typically incorporated into the analysis?
a) Material properties are directly input as constants into the element
b) Material properties are derived from the boundary conditions
c) Material properties are interpolated within the elements using shape functions
d) Material properties are irrelevant for most FEM analyses

A

a) Material properties are directly input as constants into the element

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4
Q

What consideration is typically important when selecting a solver for Finite Element Analysis?
a) The complexity of the problem geometry
b) The colour scheme used in the visualization software
c) The availability of open-source code
d) The size of the input file

A

a) The complexity of the problem geometry

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5
Q

In the Finite Element Method, what role do interpolation functions serve?
a) Defining the element’s physical properties
b) Approximating the unknown field variables within the element c) Specifying the boundary conditions
d) Defining the mesh connectivity

A

b) Approximating the unknown field variables within the element

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6
Q

How are the degrees of freedom typically defined for a beam in the
Finite Element Method?
a) Two rotational and one translational
b) Three translational in x, y, and z directions
c) One translational in the x-direction only
d) Two rotational and two translational

A

d) Two rotational and two translational

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7
Q

Why are elements with poor aspect ratios generally avoided in Finite
Element Analysis?
a) They lead to faster convergence
b) They result in more accurate solutions
c) They result in more inaccurate solutions
d) They simplify the modelling process

A

c) They result in more inaccurate solutions

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8
Q

The quality of the mesh in Finite Element Analysis (FEA) affects:
a) The colour of the plot
b) The speed of the computer
c) The accuracy of the results
d) The size of the input file

A

c) The accuracy of the results

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9
Q

What is the primary purpose of interpolation functions (shape functions) in the Finite Element Method?
a) To approximate the geometry of the elements
b) To define the material properties of the elements
c) To interpolate the unknown field variables within the elements
d) To determine the size of the finite elements

A

c) To interpolate the unknown field variables within the elements

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10
Q

In the Finite Element Method, what does the assembly process
involve?
a) Constructing the stiffness matrix
b) Breaking down the problem domain into finite elements
c) Applying boundary conditions to the system
d) Solving the system of equations iteratively

A

a) Constructing the stiffness matrix

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11
Q

What is the primary objective of mesh refinement in Finite Element
Analysis?
a) To reduce computational cost
b) To increase the number of elements
c) To improve the accuracy of the solution
d) To simplify the post-processing stage

A

c) To improve the accuracy of the solution

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12
Q

What effect does increasing mesh density have on Finite Element
Analysis?
a) Decreases computational cost
b) Increases computational accuracy
c) Speeds up convergence
d) Reduces the need for boundary conditions

A

b) Increases computational accuracy

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13
Q

Why is it important to maintain high-quality elements in a mesh?
a) It reduces the number of elements required
b) It speeds up the solution process
c) It improves the accuracy of the results
d) It allows for simpler boundary conditions

A

c) It improves the accuracy of the results

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14
Q

Under what circumstances might mesh refinement be necessary?
a) To reduce computational cost
b) To simplify the model
c) To capture localized effects or gradients
d) To decrease the number of nodes in the mesh

A

c) To capture localized effects or gradients

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15
Q

What factor(s) determine the choice of element type in meshing?
a) Material properties only
b) Geometry and physics of the problem
c) Computational cost only
d) Meshing software preferences

A

b) Geometry and physics of the problem

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16
Q

How can the quality of a mesh be assessed?
a) By its visual appearance only
b) Through quantitative measures like aspect ratio and skewness
c) By the number of elements it contains
d) By the colour of the elements in the visualization

A

b) Through quantitative measures like aspect ratio and skewness

17
Q

What does the assembly process involve in constructing the global
stiffness matrix?
a) Combining local element stiffness matrices using a simple averaging method
b) Ignoring boundary conditions to simplify the process
c) Applying element-wise multiplication between nodes
d) Summing contributions from individual elements according to their nodal connectivity

A

d) Summing contributions from individual elements according to their nodal connectivity

18
Q

Why is proper element connectivity crucial during the assembly
process?
a) It ensures that boundary conditions are correctly applied
b) It simplifies the visualization of the finite element model
c) It allows for more efficient memory allocation
d) It ensures that the global stiffness matrix is assembled correctly

A

d) It ensures that the global stiffness matrix is assembled correctly

19
Q

Which matrix storage format is commonly used to efficiently store the global stiffness matrix?
a) Dense matrix format
b) Sparse matrix format
c) Triangular matrix format
d) Diagonal matrix format

A

c) Triangular matrix format

20
Q

The Finite Element Method is fundamentally based on which of the following mathematical approaches?
a) Differential calculus
b) Variational methods
c) Probability theory
d) Fourier analysis

A

a) Differential calculus

21
Q

What does the process of discretization involve in the context of FEM?
a) Dividing the problem domain into a finite number of smaller, simpler parts called elements
b) Converting a linear problem into a nonlinear one for easier solution
c) Integrating differential equations over the entire domain at once
d) Approximating continuous variables with discrete counterparts

A

a) Dividing the problem domain into a finite number of smaller, simpler parts called elements

22
Q

What role do shape functions play in Finite Element Analysis?
a) They define the temperature distribution within each element
b) They determine the size of the elements in the mesh
c) They describe how displacement is interpolated within an element
d) They calculate the exact solution to the problem

A

c) They describe how displacement is interpolated within an element

23
Q

The global stiffness matrix in FEM represents what physical concept?
a) The work done by external loads
b) The resistance of the structure to deformation
c) The velocity of sound through the structure
d) The thermal conductivity of the material

A

b) The resistance of the structure to deformation