Forces in Pin-joint Members

Question 1

What are the assumptions made with Trusses? (pin joint frame) (7)

Answer 1

Frictionless joints

Slender members

External forces all applied at joints

Self weight can be ignored

Flexible joints (allow rotation)

Statically Determinate

Only Axial Forces (Compressive or tensile)

Question 2

You should assume the unknown member force acting on a joint to be _____________

(trusses)

Answer 2

in Tension (tensile)

Question 3

A +ve force is in ____________

A -ve force is in _____________

(Trusses)

Answer 3

Tension

Compression

Question 4

Find the Magnitude of the support reactions and internal forces in each of the members.

Answer 4

1) Start with connections that have the least number of members and work your way up

2) Always assume an unknown member is in tension ( going away from the connection/joint and +ve)

3) Symmetrical so only half has to be done.

Question 5

Find the Magnitude of the support forces and internal forces of each member

Answer 5

1) Start with connections that have the least number of members and work your way up

2) Always assume an unknown member is in tension ( going away from the connection/joint and +ve)

3) Symmetrical so only half has to be done.

Question 6

Find the Magnitude of the support forces and internal forces of each member

Answer 6

1) Start with connections that have the least number of members and work your way up

2) Always assume an unknown member is in tension ( going away from the connection/joint and +ve)

3) Symmetrical so only half has to be done.

Question 7

Find the Magnitude of the support forces and internal forces of each member

Answer 7

1) Start with connections that have the least number of members and work your way up

2) Always assume an unknown member is in tension ( going away from the connection/joint and +ve)

3) Symmetrical so only half has to be done.

Question 8

Find the Magnitude of the support forces and internal forces of each member

Answer 8

1) Start with connections that have the least number of members and work your way up

2) Always assume an unknown member is in tension ( going away from the connection/joint and +ve)

3) Symmetrical so only half has to be done.