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