A Stochastic Dynamics Method for Time-Varying Damping Depending on Temperature/Frequency for Several Alloy Materials

Area of Science:

• Materials Science
• Mechanical Engineering
• Aerospace Engineering

Background:

• Accurate response analysis is critical in aerospace and advanced manufacturing.
• Mechanical parameters of materials vary significantly with the service environment.
• Understanding damping variations is essential for structural dynamic responses.

Purpose of the Study:

• To investigate the damping variation characteristics of 304 aluminum alloy, Sa564 high-strength alloy, GW63K magnesium alloy, and Q235 steel.
• To develop a numerical method for temperature/frequency-dependent damping parameters in stochastic dynamics.
• To propose an efficient stochastic dynamics method for analyzing structural responses with variable damping.

Main Methods:

• Damping tests using dynamic mechanical analysis (DMA) to reveal variable damping ratios.
• Development of a numerical constitutive relation for temperature-dependent damping.
• Derivation of an efficient stochastic dynamics method based on the pseudo excitation method (PEM) and variable damping theory.

Main Results:

• Variable damping ratios were identified in the tested alloys and steel.
• A novel numerical method for stochastic dynamic response analysis of variable damping materials was proposed and validated.
• The proposed method demonstrated higher accuracy compared to constant damping models, especially for GW63K alloy.

Conclusions:

• The developed stochastic dynamics method accurately predicts the dynamic responses of structures with variable damping materials.
• Significant differences exist between constant damping models and experimental results, highlighting the need for variable damping analysis.
• The findings are particularly relevant for aviation, aerospace, and high-temperature applications where damping variations are pronounced.