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Unit-II Finite Element Analysis

SL.NO QUESTION AND ANSWER

1. What are the types of loading acting on the structure?

Body force (f) Traction force (T) Point load (P)2. Define the body force

A body force is distributed force acting on every eleental volue of the body

!nit" #orce per unit volue.

$%aple" &elf 'eight due to gravity. Define traction force

Traction force is defined as distributed force acting on the surface of the body.

!nit" #orce per unit area.

$%aple" #rictional resistance viscous drag surface shear*. What is point load?

Point load is force acting at a particular point 'hich causes displaceent.+. What are the basic steps involved in the finite eleent odeling

Discreti,ation of structure.

-ubering of nodes.. What is discreti,ation?

The art of subdividing a structure in to a convenient nuber of saller coponents is

/no'n as discreti,ation.0. What are the classifications of coordinates?

1lobal coordinatesocal coordinates

-atural coordinates3. What is 1lobal coordinates?

The points in the entire structure are defined using coordinates syste is /no'n as

global coordinate syste.4. What is natural coordinates?

A natural coordinate syste is used to define any point inside the eleent by a set of

diensionless nuber 'hose agnitude never e%ceeds unity. This syste is very

useful in assebling of stiffness atrices.

56. Define shape function.

7n finite eleent ethod field variables 'ithin an eleent are generally e%pressed by

the follo'ing appro%iate relation"

(x,y) = N1(x,y) 1+ N2 (x,y) 2+ N3(x,y) 3 where 1 2 3 4

are the values of the field variable at the nodes and -5 -2 - -* are

interpolation function. -5 -2 - -* are called shape functions because they

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are used to e%press the geoetry or shape of the eleent.

55. What are the characteristics of shape function?

The characteristics of the shape functions are follo's"

5. The shape function has unit value at one nodal point and ,ero value at the

other nodes.

2. The su of the shape function is e8ual to one.52. Why polynoials are generally used as shape function?

Polynoials are generally used as shape functions due to the follo'ing reasons"

5. Differentiation and integration of polynoials are 8uite easy.

2. The accuracy of the results can be iproved by increasing the order of the

polynoial.

. 7t is easy to forulate and coputeri,e the finite eleent e8uations.5. 1ive the e%pression for eleent stiffness atri%.

&tiffness atri% 9:;

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are t'o types of boundary conditions. They are

5. Priary boundary condition (or) essential boundary condition"

The boundary condition 'hich in ters of the field variables is /no'n as

priary boundary condition

2. &econdary boundary condition or natural boundary condition"

The boundary conditions 'hich are in the differential for of field variables is /no'n as

secondary boundary condition.54. What are the difference bet'een boundary value proble and initial value proble?

The solution of differential e8uation obtained for physical probles 'hich satisfies soe

&pecified conditions /no'n as boundary conditions. 7f the solution of differential e8uation

is obtained together 'ith initial conditions then it is /no'n as initial value proble. 7f the

solution of differential e8uation is obtained together 'ith boundary conditions then it is

/no'n as boundary value proble.