Piezoelectric Head Suspension Vibration Analysis Method
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Solution Overview
Problem
Current methods for analyzing the vibration properties of head suspensions with piezoelectric elements in hard disk drives are inefficient, requiring long calculation times due to the need for direct time integration and reducing accuracy when using the mode superposition method for coupled electric and structural analyses.
Innovation Solution
A method that involves obtaining displacement and reaction forces of node points on the piezoelectric element by voltage application, followed by applying these forces to perform frequency response analysis using the mode superposition method, allowing for accurate and rapid vibration property analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct time integration method (full method) is used for piezoelectric analysis, then analysis accuracy is improved, but calculation time increases significantly to 25 hours
Solution Approach 1:
The patent segments the piezoelectric analysis into two distinct modes: short-circuit condition (resonant mode) and open-circuit condition (antiresonant mode). Each mode is analyzed separately with appropriate boundary conditions, allowing the use of efficient mode superposition method while maintaining accuracy. This segmentation resolves the contradiction by enabling accurate analysis through divided calculation approaches rather than requiring the computationally intensive full method.
Solution Approach 2:
The patent performs preliminary modal analysis to calculate mode vectors and natural frequencies before conducting frequency response analysis. This preliminary calculation of mode shapes and frequencies enables the subsequent frequency response analysis to be performed efficiently using mode superposition, avoiding the need for direct time integration and significantly reducing calculation time while maintaining accuracy.
2Loss of time
If mode superposition method is used for frequency response analysis, then calculation time is reduced to 10 minutes, but analysis accuracy deteriorates for piezoelectric elements
Solution Approach 1:
The patent divides the piezoelectric analysis into two separate mode analyses: resonant mode (short-circuit condition) and antiresonant mode (open-circuit condition). Each mode is analyzed independently with appropriate boundary conditions applied to the piezoelectric element electrodes. This segmentation allows accurate frequency response analysis using mode superposition for each mode separately, resolving the accuracy issue while maintaining computational efficiency.
Solution Approach 2:
The patent changes the boundary conditions parameter for the piezoelectric element by applying either short-circuit or open-circuit conditions to the electrodes during modal analysis. This parameter change enables the mode superposition method to accurately capture the vibration properties under different electrical conditions, maintaining analysis accuracy while using the computationally efficient mode superposition approach.
3Productivity
If mode superposition method is used, then productivity is improved with faster analysis, but device complexity increases due to need for separate resonant and antiresonant mode calculations
Solution Approach 1:
The patent segments the complex piezoelectric analysis into two simpler, independent modal analyses (resonant and antiresonant modes). Each segmented analysis can be performed separately with simplified boundary conditions, making the overall complex problem manageable through division into smaller, more tractable sub-problems that can be solved efficiently.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate and speedy analysis of vibration properties, approximating natural vibration properties exhibited by voltage application, while reducing calculation time to under 10 minutes, thereby improving the management of vibration properties in head suspensions.
Implementation Method 1
The piezoelectric element is made of, for example, lead zirconate titanate (PZT) and is fixed at the part between a base plate and a load beam, or at a tongue of the head suspension. Therefore, the head can be moved slightly in a sway direction relative to the base plate with the piezoelectric element deformed in response to voltage applied thereto.
Data Source
AI summary
A method for accurately and speedy analyzing vibration property of head suspension including a piezoelectric element that moves a head according to voltage application. The method comprises a displacement obtaining step obtaining displacement of each node point of the piezoelectric element by voltage application to the piezoelectric element, a reaction force obtaining step eliminating the voltage application and applying the obtained displacement to each node point, a reaction force applying step eliminating the applied displacement and applying obtained reaction force to each node point, and an analyzing step performing the frequency response analysis by using mode superposition method.