3 leaf springs each piece structural parameters mm number number before rolling specifications (thickness @width) piece length width curvature radius arc height 1 leaf finite element calculation application I introduced the method described in the literature <2>, establish 3 springs The finite element model, as shown.
The load is also loaded by two load steps, and the stiffness of the leaf spring before and after the contact between the second piece and the third piece is 74.3 N/mm and 132.02 N/mm, respectively. The corresponding leaf spring stiffness measured by the test is 68 N/mm and The relative error of 128N/mm. finite element calculated value compared with the measured value is 9.2% and 3.1%, respectively. The load deflection curve of loading and unloading obtained by the test is shown by the solid line. The calculated load deflection curve is shown by the dashed line. It can be seen from the above that the accuracy of the finite element stiffness calculation of the three leaf springs is quite high.
Calculate the von Mises stress of the leaf spring when loading 18000 N as shown. In the middle part, the maximum stress in the left half of the leaf spring appears on the upper surface of the second piece and the U-bolt overlap, and the size is 1206 MPa (the stress in the figure is 1420 MPa is the stress concentration point appearing in the model. Abandoned), the first piece corresponds to the position stress of the third piece end, and the size is 1172 MPa. The maximum stress in the right half of the leaf spring appears on the upper surface of the second piece and the U-bolt, and the size is 1262 MPa. The first piece corresponds to the positional stress of the third piece end, and the size is 1166 MPa.
Static stress test of three leaf springs The static stress test method of the three leaf springs is described separately. Considering the finite element calculation results, the patch scheme is as shown.
Different from the 4-spring static stress test, the strain gauge is a 4-channel YD-28 dynamic strain gauge with a sensitivity coefficient of 2; only one strain flower is attached to each position. The vonMises working stress data of each measuring point of the three springs under different loads were measured. The maximum load was 18000N and the finite element calculation results were compared with the relative error D.
The vonMises stress load/N stress/MPa point of each of the three leaf springs is 1 point 2:3:4:5:00 when the load is 18000N. The vonMises stress obtained by the test is compared with the calculated result. Key point number 123456Rcal/MPa1179.4895.5873.0869.81173.4881.4Rexp /MPa1296.541897.52870.0165756.12211331.019973.3628 It can be seen that the dangerous point of the leaf spring appears at points 1 and 5. At these two points, the error between the finite element calculation result and the static stress test result is about 10%, and the calculation accuracy Can meet engineering requirements.
Comparing the results with the -2 in the literature <2>, it can be seen that the new three-leaf spring and the old four-leaf spring have a new maximum stress point, and the stress exceeds the original leaf spring material. The tensile strength is 1250 MPa, so the strength of the three springs does not meet the requirements.
It can be seen that the leaf spring finite element analysis method proposed in this paper can effectively evaluate the design of the leaf spring.
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