B4 Flashcards
According to the Maximum Shear Stress Theory, failure occurs when the maximum shear stress exceeds which of the following?
A) Tensile strength of the material
B) Yield strength in a tensile test
C) Fatigue limit of the material
D) Ultimate shear stress of the material
Yield strength in a tensile test
What is the primary purpose of stress analysis in piping systems according to piping codes?
A) To prevent brittle fracture
B) To protect against all possible failure modes
C) To address specific failure modes like plastic deformation and fatigue
D) To reduce material costs
To address specific failure modes like plastic deformation and fatigue
Which stress category is intended to prevent fatigue failure resulting from cyclic loadings?
A) Primary stress
B) Secondary stress
C) Peak stress
D) Thermal stress
Peak stress
Why are thermal stresses never classified as primary stresses?
A) They are always self-limiting
B) They do not satisfy equilibrium between forces and moments
C) They are related to brittle fracture
D) They are only caused by peak loadings
They do not satisfy equilibrium between forces and moments
Which type of stress is developed by the constraint of displacements caused by thermal expansion or imposed restraints?
A) Primary stress
B) Secondary stress
C) Peak stress
D) General primary membrane stress
Secondary stress
What distinguishes peak stresses from secondary stresses?
A) Peak stresses cause significant distortion, while secondary stresses do not
B) Peak stresses cause no significant distortion, while secondary stresses result in minor distortions
C) Secondary stresses are responsible for fatigue failure, while peak stresses are not
D) Secondary stresses are never self-limiting, while peak stresses always are
Peak stresses cause no significant distortion, while secondary stresses result in minor distortions
Which of the following is an example of a sustained load in piping systems?
A) Earthquake loads
B) Pressure and weight loads during normal operation
C) Fluid transient loads like water hammer
D) Relief valve discharge
Pressure and weight loads during normal operation
What distinguishes occasional loads from sustained loads?
A) Occasional loads occur continuously during normal operation.
B) Occasional loads are due to thermal expansion.
C) Occasional loads occur infrequently during plant operation.
D) Occasional loads are always caused by fluid transients.
Occasional loads occur infrequently during plant operation.
What type of loads are associated with expansion loads in piping systems?
A) Operating pressure and weight loads
B) Earthquake and wind loads
C) Thermal expansion and seismic anchor movements
D) Fluid transient loads
Thermal expansion and seismic anchor movements
Which of the following is not classified as a type of piping load?
A) Sustained load
B) Occasional load
C) Expansion load
D) Cyclic load
Cyclic load
Why does internal pressure in piping typically not induce loads on pipe supports?
A) Pressure forces are balanced by tension in the pipe wall
B) Pipe supports are designed to absorb all internal pressure loads
C) Pressure is always negligible compared to other loads
D) The weight of the fluid counteracts internal pressure effects
Pressure forces are balanced by tension in the pipe wall
What is the primary reason longitudinal stress develops in a pipe?
A) External loads from pipe supports
B) Internal pressure within the pipe
C) Thermal expansion of the pipe material
D) Bending moments at pipe connections
Internal pressure within the pipe
What phenomenon describes the dissipation of energy in a vibrating system?
A. Resonance
B. Damping
C. Excitation
D. Displacement
Damping
What type of analysis calculates the forces caused by hypothetical earthquakes based on time?
A. Response spectrum analysis
B. Static analysis
C. Time-history analysis
D. Cookbook-type analysis
Time-history analysis
What is the purpose of a seismic response spectrum?
A. To determine steady-state operations
B. To calculate static displacements
C. To plot maximum acceleration responses of oscillators
D. To avoid time-history calculations
To plot maximum acceleration responses of oscillators
What is the purpose of damping in seismic response?
A. To increase structural loads
B. To lower effects of seismic excitation
C. To decrease stiffness of supports
D. To improve thermal expansion tolerances
To lower effects of seismic excitation
In static seismic analysis, what is considered?
A. Real-time dynamic displacements
B. Uniform loads equivalent to earthquake accelerations
C. Thermal expansion effects
D. Operational-basis displacements
Uniform loads equivalent to earthquake accelerations
What type of system behavior does the time-history method replicate?
A. Static stress distribution
B. Instantaneous load reactions
C. Piping dynamics during seismic excitation
D. Continuous wind loading effects
Piping dynamics during seismic excitation
What is the main goal of pipe break analysis in high-energy systems?
A. To reduce thermal stresses
B. To prevent breaks near valves
C. To ensure public safety
D. To simplify computational requirements
To ensure public safety
In wind loading analysis, what does the drag coefficient depend on?
A. The shape of the obstacle
B. Pipe thermal expansion
C. Mass of the piping
D. Pipe material composition
The shape of the obstacle
Which element helps mitigate the effects of transient loads in closed-discharge systems?
A. Water seals
B. Flexible couplings
C. Thermal expansion joints
D. Reinforced anchors
Water seals
What is a virtual anchor in buried piping?
A. A fixed point on a building structure
B. A location of maximum pipe movement
C. A region with no relative motion between pipe and soil
D. A dynamic load point
A region with no relative motion between pipe and soil
What is the purpose of flexible couplings in buried piping systems?
A. Reduce soil stiffness
B. Allow axial or angular movement
C. Increase thermal expansion forces
D. Eliminate anchoring needs
Allow axial or angular movement
How are soil parameters for buried piping determined?
A. By using uniform load approximations
B. Through direct geotechnical testing
C. Using static assumptions about friction forces
D. By modeling backfill elasticity
Through direct geotechnical testing
What type of stress is typically evaluated during seismic anchor movement analysis?
A. Primary stress
B. Secondary stress
C. Combined dynamic stress
D. Static load stress
Secondary stress
How does the use of flexible couplings in buried piping impact stress?
A. It increases bending moments
B. It reduces bending moments and stresses
C. It eliminates soil forces on transverse runs
D. It doubles the stress on branch connections
It reduces bending moments and stresses
In buried piping, what is the primary effect of confining pressure?
A. It causes pipe buckling
B. It increases pipe insulation requirements
C. It acts normal to the pipe circumference
D. It eliminates axial stress
It acts normal to the pipe circumference
For buried piping with penetration anchors, what must be calculated?
A. Axial stress due to thermal expansion
B. Bending moments in the buried segment
C. Penetration reactions
D. Soil stiffness near the anchor
Penetration reactions
What is the primary cause of water hammer events in piping systems?
A. Improper valve design
B. Sudden flow interruptions or changes
C. Wind load fluctuations
D. Soil movement during seismic events
Sudden flow interruptions or changes
What are the main factors affecting stress intensification in buried piping?
A. Pipe material and insulation thickness
B. Soil deformation near elbows and branch connections
C. Length of straight pipe segments
D. Pressure variations along the pipe
Soil deformation near elbows and branch connections
In dynamic analysis of piping systems, why is damping important?
A. It increases the natural frequencies of the system
B. It provides numerical stability and reduces seismic excitation effects
C. It eliminates thermal stresses
D. It allows larger mass point spacing
It provides numerical stability and reduces seismic excitation effects
