Structural mechanics-force diagram,shear stress,elastic curve

[wkh023002]

There are totally 4 questions .i struggled for a whole day and i still cannot solve it.Please help me!
For Question 1:
My problem is that i cannot find out the reaction Ax,Ay,Dx,Dy though i establish 4 eqt:
1:Ax+Dx=90 kN
2:Ay+Dy=90 kN
3:summation Ma=0 ,anticlockwise positve
-125+2Dx+5Dy=0
4:summation Md=0 ,anticlockwise +ve
505-2Ax-5Ay=0

For Question 2:
i don't know what is the meaning of G=80kN/mm^2 and how to calculate the shear force?
also, what is Bredt-Batho theory? My professor haven't mentioned it so far.

For Question 4:
The first load from left P=WL/5 is outside the Y-axis, does it mean that i can neglect it?
to find the equation of elastic curve, do i need to establish the Moment equation for each section?

 

[PhanthomJay]

For question 1, in 2 dimensional frames, there are only 3 equations of statics external to the system that you can use in solving for external reactions...sum of Fx=0, sum of Fy=0, and sum of moments about any point = 0. The 4th equation you list is redundant. Since there are 4 unknowns, you must look at what is going on internal to the system to get your 4th equation. What do you know about the moment at the hinged joint C?

 

[piercas]

For Question 1:
It seems like you have established the correct equations for finding the reaction forces Ax, Ay, Dx, and Dy. However, there may be a mistake in your calculations as the equations should give you the values for these reaction forces. Make sure to double check your calculations and equations to ensure accuracy.

For Question 2:
G=80kN/mm^2 refers to the shear modulus of the material, which is a measure of the material's resistance to shear stress. To calculate shear force, you will need to use the equation Q = V x A, where Q is the shear force, V is the shear stress, and A is the cross-sectional area of the material.

Bredt-Batho theory is a theory used in structural mechanics to analyze the behavior of beams under bending. It takes into account the shear and axial stress distribution in addition to the bending stresses.

For Question 4:
No, you cannot neglect the first load from the left (P=WL/5). It will still contribute to the overall bending and deflection of the beam. To find the equation of the elastic curve, you will need to use the moment equation for each section of the beam, taking into account the contribution of each load.