FEA + SOM

1.what is moment ?
Ans: m=f*x
2.relation in pure bending case
m/i=sigma/y=e/r
3.if u want to calculate stress do u want material properties???
Ans: in simple cases like beam problems we don't want material property to calculate the stress
. the complex problems like other than beam problems,moment m can be calculated from the relation m=eid^2y/dx^2,we can not able to calculate the moment at any point by the applied force for complex problems.
4.what are nonlinear fem methods?
Ans:nonlinear geometry,material,contact. if the stiffness changes by geometry it is the non linear geometry. if the stiffness changes by material it is the non linear material case. if the stiffness changes due to the contact it is nonlinear contact case.
5.what is nonlinear geometry case??
Ans: if the force applied continuously for example wind turbine blades by the application of wind loads the deformation is high,in that case we must not ignore the higher order terms in strain-deflection relation strain=dy/dx+d^2y/dx^2+d^3y/dx^3+---- considering higher order terms are nonlinear geometry case. these higher order terms are called as green's function.
6.what are the theories of failures??
Ans: 1.max normal stress2.max shear stress3.vonmisses----etc
7.why u consider vonmisses stress theory only?
Ans:there is a limitations on max normal stress and max shear stress theories---etc. The vonmisses stress theory is derived from energy formulation so it is suitable for all cases and the stresses developed in the real time environment is near to the vonmisses stress.
GM
1.prrove that m=ei d^2y/dx^2
2. what is the constituency relation ship???
the relation ship between stress starin in 3 dimensional
3.what is the slope of stress strain curve after exceeding proportionality limit??
Ans: tagential modulus is the slope of the curve in the plastic region of stress strain curve
4.
MSC NASTRAN
1.shell,plate are having How many degress of freedom ??/
Ans: shell is having 6 degrees of freedom 3- translational 3 rotational degress of freedom
Plate is having 2 rotational 1- traslation degrees of freedm
solid is having 3 traslational degress pf freedom
2.what is the shape function??
Ans: read the definition from any text book
3.

4. how can you solve a cantilever beam problem in fea software
Ans: cantilever beam problem can be solved in 3 ways
1. By using beam element having 3 rotational 3 translational degress of freedom-- we will give geometric dimensions in the form as moment of inertia I
2. By using shell element---mesh with shell elements and give the thickness in the direction
then solve it for analysis
3.By using solid element --mesh with solid elements and apply the boundary conditions.. solve for analysis
Q).5. in which method u will get good results from the above 3??
Ans:1. By using beam method we can get exact results but this is valid only for beam structures, not valid for complex structures.
2. in the case of irregular sections, complex strcutures the shell element method is the best method because it allows 6 degress of freedom
3. using solid elements we can get results but the results are not correct. because it allows only 3 degress of freedom.
Q).6.in the case of shell element procedur how the stress is calculated??
Ans:in the finite element formulation the stress is calculated throught out the thickness at a node point .i.e integration from -t/2 to t/2 it will calculate