Issuu on Google+

In the frame shown below dimension H is 6m, y is 2m, L is 9m, x is 3m, l is 4m, h is 3m. External loads are: the horizontal point load P of 2kN is applied at B, the clockwise moment M of 5kNm is applied at D, the vertical uniformly distributed load w of 1kN/m is applied on bar FJ. Calculate reactions of supports. Note that this frame has two internal pins; at C and at F. What is the vertical reaction at pin support G? Give you answer in kN. Don't write dimensions.

Selected Answer:

3

Feedback: Correct. Well done. In the frame shown below dimension H is 5m, y is 2m, L is 9m, x is 3m, l is 4m, h is 3m. External loads are: the horizontal point load P of 2kN is applied at B, the clockwise moment M of 5kNm is applied at D, the vertical uniformly distributed load w of 1kN/m is applied on bar FJ. Calculate reactions of supports. Note that this frame has two internal pins; at C and at F. What is the vertical reaction at pin support G? Give you answer in kN. Don't write dimensions.

Selected Answer:

3


Question 1

2 out of 2 points One systematic way to determine internal actions in a complex 2D frame is to divide or "brake" it into a number of simpler free bodies (usually but not necessarily bars) and consider equilibrium of these free bodies one at a time. Internal forces and moments are calculated progressively for each free body and transferred onto the next one. Which of the following sequences of free bodies can be used in the written order for the analysis of the 2D frame from previous question?

Selected Answers:

JK, FJ, ABC, CDE, EFG ABC, FJK, EFG, CDE

Feedback: Correct. You can do the next question. The figure below shows the frame divided into simple free bodies. External loads, support reactions and unknown end forces are applied to each free body. Note that there are two unknown end forces where free bodies are connected in the complete structure by pin. There are two unknown end forces and a moment where free bodies are rigidly connected in the complete structure. For equilibrium of connections unknown end forces and moments are applied to the connected free bodies in opposite directions. Consider equilibrium of each free body and calculate unknown end forces. HC=[Hc] VC=[Vc] HE=[He] VE=[Ve] ME=[Me] HF=[Hf] VF=[Vf]

Specified Answer for: Hc

1

Specified Answer for: Vc

1

Specified Answer for: He

1

Specified Answer for: Ve

1

Specified Answer for: Me

-6

Specified Answer for: Hf

0


Specified Answer for: Vf

2

Feedback: Correct. Continue to the next question After you have determined end forces and moments you can draw AFD, SFD, and BMD for each free body. A final diagram of internal forces for the frame is a simple combination of these diagrams for all free bodies. Sketch diagrams for free bodies shown in the figure below and click on the bar whose SFD has step.

Selected Answer:

69, 191

Student response

In the frame shown below dimension H is 5m, y is 3m, L is 6m, x is 2m, l is 4m, h is 3m. External loads are: the vertical point load P of 3kN is applied at D, the clockwise moment M of 5kNm is applied at B, the vertical uniformly distributed load w of 1kN/m is applied on bar FJ. Repeat all steps required and determine AFD, SFD, and BMD for this frame. What is the value of BM immediatelly to the left of point D? Give you answer in kNm. Don't write dimensions.


Selected Answer:

4

Feedback: Correct. You have demonstrated sound knowledge of this topic.


Quiz 7