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FRP (Fiberglass Reinforced Plastic)
| Fiberglass-reinforced plastic (FRP) is a polymeric-glass
fiber reinforced material, composed of a gel-coated surface, glass fiber
reinforcement, and a phenolic, acrylic, or approved equal resin matrix.
The glass fiber reinforcement may be mat, fabric,
woven roving, continuous roving, chopped spun roving, or swirl mat, as
required to meet physical and process requirements. Glass content by
weight is ~ < 30% for chopped fiber / resin rich FRP (cheap, but not
recommended), ~ 30% - 55% for hand layup / rolled out FRP, and > 50%
up to 78% for vacuum bag or matched die molding. The higher the glass
content, the stronger, and less combustible the FRP product. High glass
content components can be manufactured to relatively thin cross sections
yielding durable, light weight components.
Mineral filler such as Aluminum trihydrate (ATH) is
typically used to improve flammability resistance is added at 20-50% per
resin capacity and process, but should not exceed 28% of finished weight
for preformed matched die molding process. Resin rich FRP is typically
more flammable than the same formula resin used in a high glass content
component.
It is critical that FRP components be molded, stored, and mounted
in their final, designed, shape, and not be mounted in a deformed
or stressed condition. |
| Standard: |
ASTM D618 Standard Practice
for Conditioning Plastics for Testing
| | Purpose: |
This practice defines procedures for conditioning plastics (although
not necessarily to equilibrium) prior to testing, and the conditions
under which they shall be tested.
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| Criteria: |
Specify standard name, (see below). The standard physical test
standard provides the criteria
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| Usage: |
Pre-test conditioning of test specimens shall conform to ASTM
D618
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| Standard: |
ASTM D638 Standard Test Method
for Tensile Properties of Plastics
| | Purpose: |
This test method covers the determination of the tensile properties
of unreinforced and reinforced plastics in the form of standard dumbbell-shaped
test specimens when tested under defined conditions of pretreatment,
temperature, humidity, and testing machine speed.
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| Criteria: |
Specify standard name, desired tensile strength (psi)
- (see table below) |
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| Usage: |
ASTM D638, tensile strength (XX psi)
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| Standard: |
ASTM D695 Standard Test Method
for Compressive Properties of Rigid Plastics
| | Purpose: |
This test method covers the determination of the mechanical properties
of unreinforced and reinforced rigid plastics, including high-modulus
composites, when loaded in compression at relatively low uniform rates
of straining or loading.
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| Criteria: |
Specify standard name, desired compressive strength (psi) - (see
table below)
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| Usage: |
ASTM D695, compressive strength (XX psi)
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| Standard: |
ASTM D790 Standard Test Methods
for Flexural Properties of Unreinforced and Reinforced Plastics and
Electrical Insulating Materials
| | Purpose: |
These test methods cover the determination of flexural properties
of unreinforced and reinforced plastics, including high-modulus composites
and electrical insulating materials in the form of rectangular bars
molded directly or cut from sheets, plates, or molded shapes.
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| Criteria: |
Specify standard name, desired flexural strength (psi) - (see
table below)
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| Usage: |
ASTM D790, flexural strength (XX psi)
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| Standard: |
ASTM D256 Standard Test Methods
for Determining the Izod Pendulum Impact Resistance of Plastics
| | Purpose: |
These test methods cover the determination of the resistance of
plastics to pendulum-type hammers, in breaking standard specimens
with one pendulum swing. The standard tests for these test methods
require specimens made with a milled notch. The notch produces a stress
concentration that increases the probability of a brittle, rather
than a ductile, fracture (in test methods A, C, and D). The results
of all test methods are reported in terms of energy absorbed per unit
of specimen width or per unit of cross-sectional area under the notch.
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| Criteria: |
Specify standard name, desired energy absorbed per unit of specimen
width (ft-lbs/in of notch) - (see table below)
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| Usage: |
ASTM D256, XX ft-lbs/in of notch
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| Standard: |
ASTM D2583 Standard Test Method
for Indentation Hardness of Rigid Plastics by Means of a Barcol Impressor
| | Purpose: |
This test method covers the determination of indentation hardness
of both reinforced and nonreinforced rigid plastics using a Barcol
Impressor
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| Criteria: |
Specify standard name, desired indent hardness (Barcol) - (see
table below)
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| Usage: |
ASTM D2583, XX Barcol
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| The two major methods of FRP manufacture suitable for passenger
rail vehicles are:
Method 1: Open molding, hand lay-up, or spray lay-up
(Chopper Gun, usually resin rich) - these parts are always gel-coated.
Method 2: Matched die molding, RTM, Vacuum bag,
or preform - these parts are usually not gel-coated as by application.
Pre-test conditioning of test specimens shall
conform to ASTM D618. |
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Common Properties
and Test Values
| Mechanical Property |
Test Method |
Method #1 |
Method #2 |
| Tensile Strength |
ASTM D638 |
13,000 psi |
18,000 psi |
| Compressive Strength |
ASTM D695 |
22,000 psi |
32,000 psi |
| Flexural Strength |
ASTM D790 |
21,000 psi |
28,000 psi |
| Impact |
ASTM D256 |
10 ft-lbs/ in of notch |
13 ft-lbs/ in of notch |
| Hardness |
ASTM D2583 |
45 Barcol |
45 Barcol |
| Heat |
None |
175°F Continuous |
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| Thickness |
None |
0.125 in, minimum |
0.125 in, minimum |
| Gelcoat Thickness |
None |
0.014 or 14 mils, ± 2 mils. |
N/A |
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