What is the specific gravity of FRP ventilation pipes?

The specific gravity of FRP pipe materials is usually 1.6- 1.9g/cm3, which is about steel 1/4- 1/5, higher than steel, cast iron and plastic (see Table 2 for details).

Generally speaking, the weight of FRP is not greater than 1/3 of the weight of steel pipes of the same specification, and its physical and mechanical properties are excellent (see Tables 3 and 4 for details). In addition, some physical properties of FRP pipes are also quite superior, the expansion coefficient is roughly equivalent to that of steel pipes, and the thermal conductivity is only 0.5% of that of steel pipes, so it is a good thermal insulation and electrical insulation material (see Table 5 for details).

Table 4 Mechanical performance parameters of FRP

1, pipeline 2, pipeline

Circumferential tensile strength 300MPa tensile strength 140MPa

Axial tensile strength 150MPa bending strength 135MPa.

Axial bending strength 140MPa compressive strength 130MPa.

The tensile modulus of shear strength is 9.5GPa.

The plane shear strength is 50MPa and the bending modulus is 9.0GPa.

Vertical shear strength 60MPa

The hoop tensile modulus is 25GPa.

Axial tensile modulus 12.5GPa

Shear modulus 7GPa

The bending modulus is 9.3GPa.

Performance comparison of various materials Table 5

Item coefficient \ Material fiber wound FRP steel PVC

Thermal expansion (10-6/℃)11.212.3 60-80

Heat conduction (kcal /MHC 0) 0.23 4 1 0. 18

Note: The thermal expansion coefficient of FRP is related to the ratio of lining to wall thickness. The diameter of this meter is 700 mm.

Table 2 Specific gravity and specific strength of various materials

Engineering \ material fiber wound FRP steel cast iron PVC

Specific gravity1.8-2.17.84 7.341.4

Tensile strength (MPa)160-320 380187 50-60

Specific strength100-168 48.5 25.5 36.8

Table 3 Physical and other performance parameters of FRP

Bakol hardness 40 surface resistivity 25x 10 1 1ω.

The Poisson coefficient is 0.3, and the roughness of the inner surface is 0.0084.

The elongation at break was 0.8%, and the content of food-grade residual units was 200ppm.

The shear strength of PVC-FRP layer with oxygen index of 30% is 7Mpa.

The volume resistivity is 5.5x1014ω cm.

Note: 1, the thickness of pipe fitting lining is 1.5-6mm, and its strength is ignored in structural calculation.

2. The above data are measured values of unsaturated polyester resin of a certain brand at room temperature.