A combination of flat and parabolic leaf spring analysis of GFRC leaf spring was done to improve strength and fatigue life along with other combinations of geometry. The various parameters of results analysed through CAE analysis are shown in Table 7.
Table 7
Different results of flat and parabolic GFRC leaf spring.
Sr. No. | Types of leaf spring | | Total Deformation (in mm) at 9150N | Maximum Equivalent Strain | Maximum Equivalent Stress (in MPa) | Strain Energy (in MJ) | Weight of leaf spring (in kg) | The average fatigue life of leaf spring (in Cycles) |
1. | Structural steel multi-leaf spring | | 20.605 | 0.01179 | 471.17 | 224.98 | 9.984 | 1001600 |
2. | GFRC Both flat leaf spring | | 31.564 | 0.013544 | 429.45 | 348.31 | 4.9185 | 1986000 |
3. | GFRC 1st flat leaf and 2nd parabolic leaf spring | | 40.879 | 0.030562 | 529.34 | 278.73 | 4.6569 | 2115000 |
4. | GFRC both parabolic leaf spring | | 49.49 | 0.026139 | 428.67 | 204.31 | 4.1698 | 2024800 |
5. | GFRC both parabolic leaf spring with aluminium alloy bush | | 50.199 | 0.02659 | 434.15 | 211.49 | 4.2362 | 2067700 |
The combination of flat with parabolic GFRC leaf spring has a significant effect on the various design parameters such as fatigue strength, equivalent stress and equivalent strain due to the combined effect of constant thickness of flat leaf and varying thickness of parabolic leaf, (Fig. 10–15).
Design parameters of spring steel multi-leaf spring such as fatigue strength, equivalent stress, fatigue life and strain energy are lower as compared to the case of the combination of flat and parabolic leaf spring GFRC (1st leaf flat and 2nd leaf parabolic) while there is the reduction in weight of GFRC leaf spring. It is achieved that the combination of flat and parabolic leaf spring GFRC (1st leaf flat and 2nd leaf parabolic) can sustain higher stress, absorb more strain energy and sustain more fatigue cycles. The other cases of GFRC leaf spring at Sr. No. 2,4,5 have shown improvement in several design parameters as compared to multi-leaf spring but GFRC leaf spring at Sr. No. 3 reported the highest improvement in various design parameters (Table 7).
There is a higher change in maximum equivalent strain, maximum equivalent stress and fatigue life of 1st flat leaf and 2nd parabolic leaf spring compared to the other three types of leaf spring. Higher deformation changes in the case of both parabolic leaf spring compared to the other types of leaf spring. Further, the weight of both parabolic leaf spring or flat and parabolic combination leaf spring weight is lesser as compared to both flat leaf spring combinations.
The combination of both 1st flat and 2nd parabolic GFRC leaf spring provides a higher number of fatigue life cycles as compared to the other three cases. This is due to higher maximum stress and higher maximum strain capacity as compared to others. Also, deformation is higher as compared to the case when both leaf are flat. It is expected from the discussion that the combination of both 1st flat and 2nd parabolic GFRC leaf spring may provide better strength and fatigue life compared with the combination of various geometries of leaf spring.
5.1 Verification of Results
There is no exact work is available for verification as the work is novel. However, it was compared with somewhat matching work. Birhan Alemu Tadesse and O. Fatoba Tadesse [11] worked with the Theoretical and finite element analysis (FEA) of coated composite leaf spring for heavy-duty truck application and found similar results for heavy vehicles with higher maximum equivalent stress518.29 MPa in parabolic composite leaf spring. Stress and deformation were compared with Tridedi Achyut V. and R.M. Bhoraniya [12] and found maximum equivalent stress is 587.3 MPa and deflection is 64.5mm for 65Si7 spring steel leaf spring used in similar mini truck leaf spring.
But in the present work, two leaf of GFRC leaf spring of various geometries were used and the maximum equivalent stress is 529.34 MPa and the deflection is 40.879mm for a combination of flat and parabolic composite leaf spring. The results of some parameters available in the literature do not differ much and are verified.