data and idealisation for fea of frp equipment
Post on 20-Jul-2016
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Name of the
product
Main shell wall
structure
Layer
designation
Elements to be
considered for
FEMElements to be
considered for
idealization
Idealization of
overlay
Input data for finite element analysis of FRP products
Vertical cylindrical pollution control equipment cylindrical main shell with top and
bottom covers torrispherical shapes. The cylindrical shell is supported by a skirt
support which is bolted to concrete base with 12 anchoring blocks. A drawing is
attached.
The main shell is cylindrical with its axis vertical. The shell is constructed using
alternate layers of chopped strand mat and woven roving mat. The shell is divided
into 11 segments are shown in the drawing. Between segments hat shaped FRP
stiffeners are provided. The no. of layers and correspondingly the thickness of the
shell varies from segment to segment. The layer sequence starting from inside in
all the segments are tabulated in the drawing.
The letters in the tabulated form indicated in the following structures, V - a resin
rich layer 0.5mm thickness with a veil mat not to be considered for stress analysis.
M - Chopped strand mat reinforced resin layer with 450 gsm mat nominal
thickness 1mm. R - woven roving mat reinforced resin layer with 610 gsm mat
nominal thickness 0.8mm. CRL - chemical resistant layer consisting of one veil
mat and two CSM mat layers. This is not considered for stress analysis and hence
not to be considered for FEM. S-unit - stands for a combination of
M,R,M,R,M,R,M. This unit is repeated to bulid up the entire thickness. The finite
element analysis can take each M and R separately as layers and layer properties
can be used for analysis. SH - stands for shell. Shell1 means shell in the first
segment from top. ST - stands for stiffener hat shaped made of alternate M and R
layers. TC - stands for top cot. this is only a resin layer not considered for stress
analysis.
Top cover, Main shell segments (SH1 to SH11), Stiffeners (ST1 to ST11), Bottom
cover (Torrispherical shape), Skirt support, Overlay between shell and cover,
Overlay between shell and skirt support4 node composite shell element in which properties of individual plies can be fed
in. This element can be used for top and bottom covers and cylindrical shells.
Stiffeners can be idealized as beam elements with their nodes same as that of the
same element. Skirt can also be idealized as 4 node composite shell element.
Since the overlay is only increasing the thickness locally, the layer structure and
thickness of shell elements at the location of overlay can be increased.
Output required
Loads to be
considered
No. of analysis
to be carried
outLoad data
Material
property data
Boundary
conditions
Stress
development
and load
combinations
Items to be
omitted from
the drawing
The stress and strains of individual plies CSM and WRM has to be obtained from
the analysis. The shell with maximum stress and strain of the entire product will be
identified. A biaxial failure criterian will be used for varifying wether the stresses
and strains are within the acceptable limits. Using your stress analysis data NGN
composites will carry out the use of failure criterion. The nodal displacements
must also be obtained as output to verify wether the shell undergoes excessive
deflection.
Three load cases have to be consided for stress analysis. Load case.1 -
Sustained internal pressure due to gases and liquid causing tension in the shell .It
is an axisymmetric pressure load. Load case.2 - Sustained vaccum due to
operation. It is an axisymmetric pressure load. Load case.3 - Short duration wind
loads acting on the entire shell. It is an unsymmetric pressure causing shell
bending both in axial and hoop direction. Load case.4 - Pressure loading due to
earthquake causing unsymmetric bending. It is an unsymmetric pressure causing
shell bending both in axial and hoop direction.
Stress analysis has to carried out separately for the load cases. And the stress
and strains at critical regions have to be obtained from the analysis.
All nozzles, openings, lifting lugs and anchoring legs can be ignored from the
stress analysis and the shell wall can be assumed to be continuous with no holes
or openings in the shell.
Load data for the four load cases mentioned above will be supplied as pressure
loading
The shell is attached to the concrete base to 12 anchoring legs using bolted
connections. All displacements at the locations of anchoring legs will be arrested.
the specific gravity, thickness, longitudinal tensile modulus, transverse and normal
tensile modulus, shear modulus and poisson's ratio of each CSM and WRM layers
will be supplied.
The stresses form four analysis will be taken together for the following critical load
combinations by algebraically adding stresses. Load case.1 - Only internal
pressure and self weight acts. Load case.2 - Only vaccum and self weight acts on
the shell. Load case.3 - Internal tensile pressure + wind load. load case.4 -
Internal tensile pressure + earthquake load. Load case.5 - Vaccum + Wind
pressure. Load case.6 - Vaccum + earthquake load. This part of the work will be
done by NGN Composites
Input data for finite element analysis of FRP products
Vertical cylindrical pollution control equipment cylindrical main shell with top and
bottom covers torrispherical shapes. The cylindrical shell is supported by a skirt
support which is bolted to concrete base with 12 anchoring blocks. A drawing is
attached.
The main shell is cylindrical with its axis vertical. The shell is constructed using
alternate layers of chopped strand mat and woven roving mat. The shell is divided
into 11 segments are shown in the drawing. Between segments hat shaped FRP
stiffeners are provided. The no. of layers and correspondingly the thickness of the
shell varies from segment to segment. The layer sequence starting from inside in
all the segments are tabulated in the drawing.
The letters in the tabulated form indicated in the following structures, V - a resin
rich layer 0.5mm thickness with a veil mat not to be considered for stress analysis.
M - Chopped strand mat reinforced resin layer with 450 gsm mat nominal
thickness 1mm. R - woven roving mat reinforced resin layer with 610 gsm mat
nominal thickness 0.8mm. CRL - chemical resistant layer consisting of one veil
mat and two CSM mat layers. This is not considered for stress analysis and hence
not to be considered for FEM. S-unit - stands for a combination of
M,R,M,R,M,R,M. This unit is repeated to bulid up the entire thickness. The finite
element analysis can take each M and R separately as layers and layer properties
can be used for analysis. SH - stands for shell. Shell1 means shell in the first
segment from top. ST - stands for stiffener hat shaped made of alternate M and R
layers. TC - stands for top cot. this is only a resin layer not considered for stress
analysis.
Top cover, Main shell segments (SH1 to SH11), Stiffeners (ST1 to ST11), Bottom
cover (Torrispherical shape), Skirt support, Overlay between shell and cover,
Overlay between shell and skirt support4 node composite shell element in which properties of individual plies can be fed
in. This element can be used for top and bottom covers and cylindrical shells.
Stiffeners can be idealized as beam elements with their nodes same as that of the
same element. Skirt can also be idealized as 4 node composite shell element.
Since the overlay is only increasing the thickness locally, the layer structure and
thickness of shell elements at the location of overlay can be increased.
The stress and strains of individual plies CSM and WRM has to be obtained from
the analysis. The shell with maximum stress and strain of the entire product will be
identified. A biaxial failure criterian will be used for varifying wether the stresses
and strains are within the acceptable limits. Using your stress analysis data NGN
composites will carry out the use of failure criterion. The nodal displacements
must also be obtained as output to verify wether the shell undergoes excessive
deflection.
Three load cases have to be consided for stress analysis. Load case.1 -
Sustained internal pressure due to gases and liquid causing tension in the shell .It
is an axisymmetric pressure load. Load case.2 - Sustained vaccum due to
operation. It is an axisymmetric pressure load. Load case.3 - Short duration wind
loads acting on the entire shell. It is an unsymmetric pressure causing shell
bending both in axial and hoop direction. Load case.4 - Pressure loading due to
earthquake causing unsymmetric bending. It is an unsymmetric pressure causing
shell bending both in axial and hoop direction.
Stress analysis has to carried out separately for the load cases. And the stress
and strains at critical regions have to be obtained from the analysis.
All nozzles, openings, lifting lugs and anchoring legs can be ignored from the
stress analysis and the shell wall can be assumed to be continuous with no holes
or openings in the shell.
Load data for the four load cases mentioned above will be supplied as pressure
loading
The shell is attached to the concrete base to 12 anchoring legs using bolted
connections. All displacements at the locations of anchoring legs will be arrested.
the specific gravity, thickness, longitudinal tensile modulus, transverse and normal
tensile modulus, shear modulus and poisson's ratio of each CSM and WRM layers
will be supplied.
The stresses form four analysis will be taken together for the following critical load
combinations by algebraically adding stresses. Load case.1 - Only internal
pressure and self weight acts. Load case.2 - Only vaccum and self weight acts on
the shell. Load case.3 - Internal tensile pressure + wind load. load case.4 -
Internal tensile pressure + earthquake load. Load case.5 - Vaccum + Wind
pressure. Load case.6 - Vaccum + earthquake load. This part of the work will be
done by NGN Composites
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