Method for measuring bending fatigue life of forged aluminum alloy hub

Abstract

A method for measuring the bending fatigue life of a forged aluminum alloy hub belongs to the technical field of automobile hub manufacturing, and is characterized by comprising the following steps: 1) under the condition of not considering the influence of other external forces, according to a hub bending fatigue test, only the acting force of a bending load on a hub connecting rod; and (2) according to the fatigue damage accumulation theory, the maximum stress Smax and the minimum stress Smin of the forged aluminum alloy hub under the action of the bending moment, the average stress S and the fatigue damage D of the hub are calculated, and the relation among the average stress S, the fatigue damage D and the bending fatigue life N of the forged aluminum alloy hub is directly designed. The method has the advantages that the relationship with the bending fatigue life of the hub can be determined through the average stress and fatigue damage of the hub, the fatigue life of the hub is rapidly measured, and the actual experiment cost is saved.

Description

Technical Field

[0001] This invention belongs to the field of automotive wheel manufacturing technology, specifically relating to a method for determining the bending fatigue life of forged aluminum alloy wheels. Background Technology

[0002] As a crucial component of the vehicle system, the wheel is the only part that connects the car to the ground, making it a key focus of automotive safety. While the wheel hub houses the tire to reduce the direct impact of the ground on it, the actual working environment of the wheel is complex. Subjected to prolonged cyclic loads, the wheel's stability, reliability, and effectiveness inevitably decline, leading to minor cracks and fractures, and even severe fatigue damage, resulting in dangerous traffic accidents. Statistics show that most wheel damage is fatigue failure, a type of damage that is unpredictable and extremely dangerous. Therefore, fatigue testing of wheels is necessary. These tests are conducted on specialized fatigue testing machines and typically require 10 hours of operation. 5 For tests involving more than one cycle, the running time can take several days or even weeks, resulting in a long testing cycle and higher costs for determining fatigue life.

[0003] my country's research and development of new automotive and component products using modern design methods is still in its initial stage. To expand its development prospects, it is necessary to independently develop a CAE / CAM system suitable for my country's actual conditions, specifically for static and dynamic finite element analysis of domestic wheels. This invention uses the finite element method to simulate the actual bending fatigue life of wheels. This method can provide virtual evaluation during wheel hub development, identifying stress concentration points and areas with short lifespans as early as possible, discovering wheel hub design defects, and improving product productivity. Therefore, combining virtual calculation analysis based on this method with representative verification tests can improve efficiency and reduce costs. Summary of the Invention

[0004] The present invention provides a method for determining the bending fatigue life of forged aluminum alloy wheel hubs, which can effectively solve the shortcomings of the existing technology.

[0005] The objective of this invention is achieved by comprising the following steps: (1) Determine the bending fatigue life of forged aluminum alloy wheel hubs. Under the condition that other external forces are not considered, only the bending moment acts on the wheel hub. Construct a finite element numerical simulation of wheel hub bending fatigue. Based on the fatigue damage accumulation theory, directly design the relationship between wheel hub bending fatigue life and cyclic load and fatigue damage. (2) Based on the wheel hub bending fatigue life simulation, the maximum stress S of the wheel hub under cyclic load is max Minimum stress S min The mean stress S was calculated as follows: S=( |Smax |+|S min |) / 2 (1) (3) Based on the fatigue damage D that occurs under cyclic loading, the design formula for the bending fatigue life N of the forged aluminum alloy wheel hub is determined, where N is the number of cycles the wheel hub can withstand: N=(2806055-16017.39958×S) / (2-0.03602×S+1.641522×10 -4 ×S 2 ) +0.431035 / (D-2.24463×10 -9 )+0.98×10 6 (2) (4) The forged aluminum alloy material is 6061.

[0006] According to the method for determining the bending fatigue life of a forged aluminum alloy wheel hub, the bending fatigue life N of the wheel hub can also be obtained from the following table.

[0007] Data table of fatigue life, stress, and wheel damage of forged aluminum alloy wheels Maximum stress Smax / MPa 107.4 102.2 57.29 125.9 127.7 112.2 128.9 122.2 121.2 Minimum stress Smin / MPa -132.6 -147.7 -196.7 -134.1 -143.3 -170.6 -162.7 -176 -186.9 Fatigue damage D 2.42×10-8 3.91×10-8 4.84×10-8 6.44×10-8 1.07×10-7 1.58×10-7 2.61×10-7 3.42×10-7 5.10×10-7 Fatigue life N / number of cycles 41968479 25627372 20886955 15818870 9868423 6613509 4625501 3748229 2805520 Advantages and positive effects of this invention: Because this invention does not consider the influence of other external forces in the finite element simulation software, it only considers the influence of bending moment on the wheel hub based on the principle of wheel bending experiments. The maximum stress S of the wheel hub under bending load is thus determined. max Minimum stress S min Based on the cumulative fatigue damage theory, the relationship between the average stress S, fatigue damage D, and the fatigue life N of the wheel hub was determined directly using the average stress S and fatigue damage D. For forged aluminum alloy wheels made of different materials, the bending fatigue life of the forged aluminum alloy wheel hub can be quickly calculated according to this relationship, improving the efficiency of fatigue life detection in wheel hub bending tests and providing a scientific and reasonable theoretical basis for determining the bending fatigue life of forged aluminum alloy wheel hubs. Attached Figure Description

[0008] Figure 1 Flowchart for determining the bending fatigue life of forged aluminum alloy wheel hubs. Detailed Implementation

[0009] The method for determining the bending fatigue life of forged aluminum alloy wheel hubs according to the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0010] Example 1 according to Figure 1 The flowchart for bending fatigue simulation shows that the parameters set in this embodiment are: the maximum stress S experienced by the forged aluminum alloy wheel hub. max=107.4MPa, minimum stress S min =-132.6MPa, fatigue damage D=2.42×10 -8 The design steps for determining the bending fatigue life of forged aluminum alloy wheels are as follows: (1) Determine the bending fatigue life of forged aluminum alloy wheel hubs. Under the condition that other external forces are not considered, only the bending moment acts on the wheel hub. Construct a finite element numerical simulation of wheel hub bending fatigue. Based on the fatigue damage accumulation theory, directly design the relationship between wheel hub bending fatigue life and load spectrum and fatigue damage. (2) Based on the wheel hub bending fatigue life simulation, the maximum stress S of the wheel hub under cyclic load is max Minimum stress S min The mean stress S was calculated as follows: S=(|107.4|+|-132.6|) / 2=120 MPa (1) (3) Based on the damage D that occurs under cyclic loading, the bending fatigue life N of the forged aluminum alloy wheel hub is determined: N=(2806055-16017.39958×120) / (2-0.03602×120+1.641522×10 -4 ×120 2 ) +0.431035 / (2.42×10 -8 -2.24463×10 -9 )+0.98×10 6 =41968479 (2) The fatigue life was calculated to be N=41,968,479, meaning the hub can withstand fatigue life up to 41,968,479 hours under average stress and fatigue damage of S=120MPa and D=2.42×10⁻⁶ MPa. -8 The minimum number of iterations is 41,968,479.

[0011] Example 2 according to Figure 1 The flowchart for bending fatigue simulation shows that the parameters set in this embodiment are: the maximum stress S experienced by the forged aluminum alloy wheel hub. max =127.7MPa, minimum stress S min =-143.3MPa, fatigue damage D=1.07×10 -7 The design steps for determining the bending fatigue life of forged aluminum alloy wheels are as follows: (1) Determine the bending fatigue life of forged aluminum alloy wheel hubs. Under the condition that other external forces are not considered, only the bending moment acts on the wheel hub. Construct a finite element numerical simulation of wheel hub bending fatigue. Based on the fatigue damage accumulation theory, directly design the relationship between wheel hub bending fatigue life and load spectrum and fatigue damage. (2) Based on the wheel hub bending fatigue life simulation, the maximum stress S of the wheel hub under cyclic load is max Minimum stress S min The mean stress S was calculated as follows: S=(|127.7|+|-143.3|) / 2=135.5 MPa (1) (3) Based on the damage D that occurs under cyclic loading, the bending fatigue life N of the forged aluminum alloy wheel hub is determined: N=(2806055-16017.39958×135.5) / (2-0.03602×135.5+1.641522×10 -4 ×135.5 2 ) +0.431035 / (1.07×10 -7 -2.24463×10 -9 )+0.98×10 6 =9868423 (2) The fatigue life was calculated to be N=9868423, meaning the hub can withstand fatigue life up to 9868423 hours with average stress and fatigue damage of S=135.5MPa and D=1.07×10⁻⁶ MPa. -7 The minimum number of iterations is 9,868,423.

[0012] Example 3 according to Figure 1 The flowchart for bending fatigue simulation shows that the parameters set in this embodiment are: the maximum stress S experienced by the forged aluminum alloy wheel hub. max =121.2MPa, minimum stress S min =-186.9MPa, fatigue damage D=5.10×10 -7 The design steps for determining the bending fatigue life of forged aluminum alloy wheels are as follows: (1) Determine the bending fatigue life of forged aluminum alloy wheel hubs. Under the condition that other external forces are not considered, only the bending moment acts on the wheel hub. Construct a finite element numerical simulation of wheel hub bending fatigue. Based on the fatigue damage accumulation theory, directly design the relationship between wheel hub bending fatigue life and load spectrum and fatigue damage. (2) Based on the wheel hub bending fatigue life simulation, the maximum stress S of the wheel hub under cyclic load is max Minimum stress S min The mean stress S was calculated as follows: S=(|121.2|+|-186.9|) / 2=154.05 MPa (1) (3) Based on the damage D that occurs under cyclic loading, the bending fatigue life N of the forged aluminum alloy wheel hub is determined: N=(2806055-16017.39958×154.05) / (2-0.03602×154.05+1.641522×10 -4 ×154.05 2 ) +0.431035 / (5.10×10 -7 -2.24463×10 -9 )+0.98×10 6 =2805520 (2) The fatigue life was calculated to be N=2805520, meaning the hub can withstand fatigue life up to 2805520 hours. The average stress and fatigue damage were calculated to be S=154.05MPa and D=5.10×10⁻⁶ MPa, respectively. -7 The minimum number of iterations is 2,805,520.

Claims

1. A method for determining the bending fatigue life of forged aluminum alloy wheel hubs, characterized in that... Follow these steps to achieve the following: (1) To determine the bending fatigue life of forged aluminum alloy wheel hubs, without considering the influence of other external forces, only the bending load is applied to the tail of the wheel hub connecting rod, and then a bending moment is applied to the wheel hub shaft hole from the top of the connecting rod. The finite element numerical simulation of wheel hub bending fatigue is constructed. Based on the fatigue damage accumulation theory, the relationship between wheel hub bending fatigue life and cyclic load and fatigue damage is directly designed. (2) Based on the wheel hub bending fatigue life simulation, the maximum stress of the wheel hub under cyclic load is S max Minimum stress S min Calculate the average stress S : S =( | S max |+| S min |) / 2 （1） (3) Then, based on the fatigue damage that occurs under cyclic loading D The bending fatigue life of forged aluminum alloy wheel hubs was determined. N Design formula, N Wheel hub cycle count: N =(2806055-16017.39958× S ) / (2-0.03602× S +1.641522×10 -4 × S 2 ) +0.431035 / ( D -2.24463×10 -9 )+0.98×10 6 (2) (4) The forged aluminum alloy material is 6061.

2. The method for determining the bending fatigue life of a forged aluminum alloy wheel hub according to claim 1, characterized in that, Wheel hub bending fatigue life N You can also find this information in the table below.

3. Data table of fatigue life, stress, and fatigue damage of forged aluminum alloy wheels.

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