Fatigue Analysis of Rounded Straight Beam Flexible Hinge_Hinge Knowledge_Tallsen

Abstract: The fatigue performance of flexible hinges, especially those with special notch shapes, has not been extensively studied. This research aims to analyze the fatigue performance of composite flexible hinges, which offer improved strength, positioning accuracy, and fatigue resistance compared to typical flexible hinges. Finite element simulation experiments were conducted to calculate the fatigue life of rounded straight beam flexible hinges, providing valuable insights for the engineering design of new flexible hinges.

Flexible hinges play a crucial role in compliant mechanisms, but they often suffer from limitations such as limited movement space, weak strength, and narrow application scope. Composite flexible hinges offer a solution to these problems, exhibiting reduced clearance, increased positioning accuracy, and enhanced fatigue performance. In recent years, computer simulation technology, particularly finite element analysis, has become increasingly popular in product development. This study focuses on the use of finite element fatigue simulation technology to analyze the fatigue life distribution of composite flexible hinges, allowing for early identification of weak points in the design phase.

Fatigue Analysis Method and Process:

Fatigue analysis refers to the evaluation of material damage and failure under cyclic loading. Two commonly observed forms of fatigue damage include low cycle fatigue and high cycle fatigue. The fatigue analysis method employed depends on the type of fatigue damage. Traditional methods such as nominal stress, local stress-strain, stress field strength, and energy methods have been widely used in engineering design. However, finite element fatigue simulation technology offers several advantages over traditional methods, including the determination of fatigue life distribution on part surfaces, avoidance of bad designs, and early identification of weak positions in the initial design stage.

Methodology:

To analyze the fatigue performance of rounded straight beam flexible hinges, a mathematical model was established using finite element analysis software (ANSYS). The model considered geometric parameters, such as width, height, thickness, radius, and length of the straight beam part. Finite element simulations were conducted to determine the bending normal stress distribution of the flexible hinge under different loads. The stress results showed the maximum stress was located at the junction of the two notch shapes.

Fatigue Analysis of Rounded Straight Beam Flexible Hinges:

The fatigue analysis of rounded straight beam flexible hinges involved importing the stress distribution obtained from finite element analysis into a fatigue analysis system. The appropriate S-N curve of the material was selected, and the load spectrum was inputted. The fatigue analysis provided insights into the fatigue life of the flexible hinge's weak position. The analysis considered the maximum stress node and revealed a fatigue life of approximately 617,580 cycles. It was categorized as high cycle fatigue.

Through finite element simulation experiments, this research successfully analyzed the fatigue performance of rounded straight beam flexible hinges. The results indicated that composite flexible hinges, including rounded straight beam types, demonstrated better fatigue strength compared to traditional flexible hinges. However, further research is required to explore other curved flexible hinges, such as hyperbola, ellipse, and parabola. The findings contribute to the understanding of fatigue behavior in composite flexible hinges and provide a theoretical basis for engineering design improvement.