Mechanical Behavior of Helical Spring Made of Composite with and without Material Property Grading under Stable Load

Table 2

3K carbon fiber properties.

Tow size	Filament properties					Minimum carbon content (%)
	Tensile strength (GPa)	Young’s modulus (GPa)	Diameter ( m)	Elongation (%)	Density (g cm^-3)
3	3.75	231	7.0	1.4	1.76	92

Source: [9].