NOTE-2: Free Code:
Anchor or Restraints from equipment connections which are very near to the hangers are usually freed during the hanger design restrained weight run, so that loads normally going to the equipment nozzle are carried by the hanger.
The hanger can be designed to take almost the full weight of the pipe between the anchor and the hanger.
Using this field enter the node number & the direction in which free code is to be used.
Free Codes are:-
1. Free the anchor or restraint in the Y direction only.
2. Free the anchor or restraint in the Y and X directions only.
3. Free the anchor or restraint in the Y and Z directions only.
4. Free all translational degrees of freedom for the anchor or restraint. (X, Y and Z)
5. Free all translational and rotational degrees of freedom for the anchor or restraint. (X, Y, Z, RX, RY, and RZ). Refer Figure below.
The option 5 above usually results in the highest adjacent hanger loads, but should only be used when the horizontal distance between the hanger and the anchor is within about 4 pipe diameters as shown in below Figure
Anchor or Restraints from equipment connections which are very near to the hangers are usually freed during the hanger design restrained weight run, so that loads normally going to the equipment nozzle are carried by the hanger.
The hanger can be designed to take almost the full weight of the pipe between the anchor and the hanger.
Using this field enter the node number & the direction in which free code is to be used.
Free Codes are:-
1. Free the anchor or restraint in the Y direction only.
2. Free the anchor or restraint in the Y and X directions only.
3. Free the anchor or restraint in the Y and Z directions only.
4. Free all translational degrees of freedom for the anchor or restraint. (X, Y and Z)
5. Free all translational and rotational degrees of freedom for the anchor or restraint. (X, Y, Z, RX, RY, and RZ). Refer Figure below.
The option 5 above usually results in the highest adjacent hanger loads, but should only be used when the horizontal distance between the hanger and the anchor is within about 4 pipe diameters as shown in below Figure
NOTE-3:
Number of hangers at location:
For better stability, the base type spring support of 24″ and larger is used with 2 spring cans.
Number of hangers at location:
For better stability, the base type spring support of 24″ and larger is used with 2 spring cans.
Few important points to keep in mind while Spring selection:
•For can type springs the spring height should be kept minimum from stability point of view. If spring height is less the moment on spring will reduce and tilting of spring (below Figure) can be avoided or significantly minimized.
•The spring which has lower spring rate will have lower load variation.
•While designing the spring hanger the sustained sagging should be minimized within +/-(1 ~ 2) mm so that original piping system is not strained much.
•The spring which has lower spring rate will have lower load variation.
•While designing the spring hanger the sustained sagging should be minimized within +/-(1 ~ 2) mm so that original piping system is not strained much.
CAE Piping performs the Pipe Support Stress Analysis based on ASME and AISC codes . We perform the structural analyses based on ASME section VIII for the supporting structures of the piping systems evaluated by ASME B31 codes. We use ASME section III for the analysis of pipe supports of the nuclear piping systems.
Beside data provided in ASME codes and WRC's Bulletins, CAEP performs advanced finite element analysis to estimate the SIFs (Stress Intensification Factors) for different piping components like as tees, bends, etc.
CAE Piping offers structural and failure analyses consulting services: Performing structural analyses and mechanical failure analyses (Fatigue,ratcheting, shake down, limit load and fracture mechanics analyses and ...) for the welded components, pipelines and storage tanks, turbine blades, boiler components, aerospace and other mechanical components.
We specialize in examination of the fracture surfaces to determine the type and direction of the crack propagation, estimating the remain life of the cracked components and providing solutions to stop the crack propagation or designing the improved replacement part.
There exists a number of possible failure modes that we take into consideration in the design of piping systems and mechanical components. We provide the Root Cause Failure Analysis (RCFA), identifying the root causes of faults or problems in mechanical components, piping system and supporting structures, utilizing finite element analysis.
The failure analysis services are carried out in two steps:
We specialize in examination of the fracture surfaces to determine the type and direction of the crack propagation, estimating the remain life of the cracked components and providing solutions to stop the crack propagation or designing the improved replacement part.
There exists a number of possible failure modes that we take into consideration in the design of piping systems and mechanical components. We provide the Root Cause Failure Analysis (RCFA), identifying the root causes of faults or problems in mechanical components, piping system and supporting structures, utilizing finite element analysis.
The failure analysis services are carried out in two steps:
First Step: Design by linear elastic analysis based on ASME Section III or Section VIII:
Limit on primary stress to prevent plastic deformation.
Limit on primary plus secondary stress to prevent excessive plastic deformation.
Limit on peak stress to prevent fatigue failure due to cyclic loading.
Limit on primary stress to prevent plastic deformation.
Limit on primary plus secondary stress to prevent excessive plastic deformation.
Limit on peak stress to prevent fatigue failure due to cyclic loading.
Second Step: Design by nonlinear analysis based on ASME Section III or Section VIII (utilizing finite element analysis):
- Limit load analysis
CAEP uses the Limit load analysis to investigate limit loads of the pipe supports and mechanical components, if required. The limit load is the load level which the deformation growths without limit if the material of the structure is considered as ideal elastic-plastic (material with zero strain hardening).
CAEP uses the Limit load analysis to investigate limit loads of the pipe supports and mechanical components, if required. The limit load is the load level which the deformation growths without limit if the material of the structure is considered as ideal elastic-plastic (material with zero strain hardening).
- Failure analysis under cyclic loading (Low / high cycle fatigue analysis):
We perform fatigue analysis on piping systems, pressure vessels, components and welded structures to investigate the cyclic damage and the minimum life cycles and the possibility of the crack initiation.
We perform fatigue analysis on piping systems, pressure vessels, components and welded structures to investigate the cyclic damage and the minimum life cycles and the possibility of the crack initiation.
- Mechanical ratcheting analysis:
We perform ratcheting analysis on the piping systems and pressure vessels to investigate the ratcheting failure mode. This failure mode is due to the accumulation of plastic strains due to cyclic loading. The stress level should be severe enough to reach such a plastic accumulation. The driving force of the ratcheting distortion is primary membrane stress and then alternating stresses is needed.
We perform ratcheting analysis on the piping systems and pressure vessels to investigate the ratcheting failure mode. This failure mode is due to the accumulation of plastic strains due to cyclic loading. The stress level should be severe enough to reach such a plastic accumulation. The driving force of the ratcheting distortion is primary membrane stress and then alternating stresses is needed.
- Thermal ratcheting analysis:
We perform thermal ratcheting analysis too. Thermal ratcheting failure mode is the progressive growth of pipe-diameter when the constant pressure, hoop stress, and alternating thermal gradient are applied through the thickness of the piping systems or pressure vessels.
We perform thermal ratcheting analysis too. Thermal ratcheting failure mode is the progressive growth of pipe-diameter when the constant pressure, hoop stress, and alternating thermal gradient are applied through the thickness of the piping systems or pressure vessels.
- Shake down analysis:
We check the possibility of occurrence of the material shake down on the pressure vessels, piping systems and components under structural and thermal transient loads.
Elastic shake-down occurs if the material accumulates plastic strain in the first few cycles but subsequently behaves completely elastically.
We check the possibility of occurrence of the material shake down on the pressure vessels, piping systems and components under structural and thermal transient loads.
Elastic shake-down occurs if the material accumulates plastic strain in the first few cycles but subsequently behaves completely elastically.