TRUSSES

Question 1

What are the DIFFERENCES BETWEEN TRUSSES AND BEAMS?

Answer 1

Truss (Bar):
* Axial load and motion only
* Carry no moment

Beam:
* Carry moment and rotation
* Can have shear motion out of or not along the length of the element

Question 2

What is a PLANE TRUSS?

Answer 2

A truss where all members lie in a single plane

Question 3

What is STATIC STRUCURAL ANAYSIS?

Answer 3

• Calculates the effects of STEADY LOADING CONDITIONS
• IGNORES INERTIA FORCES
• Determines DISPLACEMENTS, STRESSES, etc

Question 4

What is MODAL ANALYSIS?

Answer 4

• Used to calculate the vibration characteristics (natural frequencies and mode shapes)
• Natural frequencies and mode shapes are important parameters in the design of a structure for dynamic loading

Question 5

What is HARMONIC ANALYSIS?

Answer 5

• Any sustained CYCLIC LOAD produces a sustained CYCLIC RESPONSE
• Determines the response of a structure to harmonically time-varying loads
• Ability to predict the sustained DYNAMIC BEHAVIOUR of a structure
• Allows for verification on whether structures can withstand RESONANCE, FATIGUE, VIBRATIONS

Question 6

What is TRANSIENT DYNAMIC ANALYSIS?

Answer 6

• AKA TIME-HISTORY analysis
• Determines the dynamic response of a structure under any general TIME-DEPENDENT loads.
• All nonlinearities available under static analysis are allowed

Question 7

What is SPECTRUM ANALYSIS?

Answer 7

• When the results of a MODAL ANALYSIS are used with a KNOWN SPECTRUM to calculate DISPLACEMENTS AND STRESSES in a model
• Mainly used IN PLACE OF A TIME-HISTORY ANALYSIS to determine the response of structures to random or time-dependent loading conditions
• EARTHQUAKES, OCEAN WAVE LOADS, JET ENGINE THRUST, ROCKET MOTOR VIBRATIONS, WIND LOADS etc

Question 8

What is BUCKLING ANALYSIS?

Answer 8

• Used to determine; BUCKLING LOADS or BUCKLED MODE SHAPES
• two types
  - NONLINEAR buckling analysis
  - EIGENVALUE (linear) buckling analysis

Question 9

What is a SPACE TRUST?

Answer 9

• 3D truss
• Simple space truss has 6 members in a tetrahedron
• All loads must be applied at the joints