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

Table 1

Geometrical dimensions of the square cross section for the validation of composite spring.

Lamina coiled	Square cross section (Figure 2)	Side length of square cross section (mm)	Perimeter (mm)	Carbon fiber lamina total length (cm)
1	a	3.84	15.36	37.5
2	b	4.28	17.12
3	c	4.72	18.88
4	d	5.16	20.64
5	e	5.60	22.40
6	f	6.04	24.16
7	g	6.48	25.92
8	h	6.92	27.68
9	i	7.36	29.44
10	j	7.80	31.20
11	k	8.24	32.96
12	l	8.68	34.72
13	m	9.12	36.48
14	n	9.56	38.24