Comparability of Mechanical‐Impedance Measurements

1962 ◽  
Vol 34 (5) ◽  
pp. 731-731
Author(s):  
R. O. Belsheim ◽  
G. M. Remmers
Keyword(s):  
Mechanical Impedance ◽  
Impedance Measurements

scholarly journals Comparison of Mechanical Impedance Methods for Vibration Simulation

1996 ◽  
Vol 3 (3) ◽  
pp. 223-232 ◽  
Author(s):  
Jeffrey A. Gatscher ◽  
Grzegorz Kawiecki
Keyword(s):  
Mechanical Impedance ◽  
Field Measurements ◽  
Cumulative Damage ◽  
Vibration Test ◽  
Element Analysis ◽  
Impedance Measurements ◽  
Testing Strategies ◽  
Impedance Testing ◽  
Vibration Simulation ◽  
Test Requirements

The work presented here explored the detrimental consequences that resulted when mechanical impedance effects were not considered in relating vibration test requirements with field measurements. The ways in which these effects can be considered were evaluated, and comparison of three impedance methods was accomplished based on a cumulative damage criterion. A test structure was used to simulate an equipment and support foundation system. Detailed finite element analysis was performed to aid in computation of cumulative damage totals. The results indicate that mechanical impedance methods can be effectively used to reproduce the field vibration environment in a laboratory test. The establishment of validated computer models, coupled with laboratory impedance measurements, can eliminate the overtesting problems inherent with constant motion, infinite impedance testing strategies.

scholarly journals Crack Detection in Shafts Using Mechanical Impedance Measurements

2012 ◽  
Vol 2 (2) ◽  
Author(s):  
Abdualhakim Ahmed Tlaisi ◽  
Arisi S. Swamidas ◽  
Ayhan Akinturk ◽  
Mahmoud R Haddara
Keyword(s):  
Crack Detection ◽  
Mechanical Impedance ◽  
Impedance Measurements

scholarly journals A New Damage Detecting Method by Mechanical Impedance Measurements

1980 ◽  
Vol 23 (186) ◽  
pp. 2125-2131 ◽  
Author(s):  
Kikuo NEZU ◽  
Hidenori KIDOGUCHI
Keyword(s):  
Mechanical Impedance ◽  
Impedance Measurements ◽  
Detecting Method

Electro-Mechanical Impedance Measurements as a Possible SHM Method for Sandwich Debonding Detection

2017 ◽  
Vol 742 ◽  
pp. 763-777 ◽  
Author(s):  
Christoph Kralovec ◽  
Martin Schagerl
Keyword(s):  
Present Article ◽  
Health Monitoring ◽  
Sandwich Panel ◽  
Mechanical Impedance ◽  
Impedance Method ◽  
Constant Thickness ◽  
Fem Model ◽  
Impedance Measurements ◽  
Coupled Field ◽  
Debonding Detection

The present article addresses the evaluation of the electro-mechanical (E/M) impedance method as a Structure Health Monitoring (SHM) method to detect and classify damage, more specific, the debonding of a face layer.In the study the considered structure is simplified as a circular sandwich panel of constant thickness, consisting of isotropic face layers and a honeycomb core.The debonding is assumed to be circular and situated at the center of the panel, only variable in its radius.The article starts with a brief introduction to the basic idea of SHM and the fundamentals of the E/M impedance method.Further, the idealized setting is investigated by two sets of experiments whose results are analyzed by typically used damage metrics and by considering both analytical and numerical models.A coupled-field FEM model is developed and compared to the experimental results.Furthermore, an analytical model is derived to evaluate the experimental and numerical results.All results are presented and discussed extensively on pursuing the objective to detect and classify the size of a debonding.Finally, it is shown how a model based approach can predict the presence but also the size of a debonding in the considered sandwich panels based on the E/M impedance measurements.

Mechanical impedance measurements of CFRP cross-ply laminates using central vibration tests

2017 ◽  
Vol 2017 (0) ◽  
pp. 337
Author(s):  
Tatsuya TAKAISHI ◽  
Kohji SUZUKI ◽  
Hiroshi SAITO ◽  
Isao KIMPARA
Keyword(s):  
Mechanical Impedance ◽  
Impedance Measurements ◽  
Vibration Tests

Internal Porosity Detection in Additively Manufactured Parts via Electromechanical Impedance Measurements

2017 ◽  
Author(s):  
Charles Tenney ◽  
Mohammad I. Albakri ◽  
Joseph Kubalak ◽  
Logan D. Sturm ◽  
Christopher B. Williams ◽  
...  
Keyword(s):  
Piezoelectric Materials ◽  
Mechanical Impedance ◽  
Sensors And Actuators ◽  
Impedance Measurements ◽  
Electromechanical Impedance ◽  
Internal Porosity ◽  
Industrial Adoption ◽  
Piezoelectric Wafers ◽  
Porosity Detection ◽  
The Impact

The flexibility offered by additive manufacturing (AM) technologies to fabricate complex geometries poses several challenges to non-destructive evaluation (NDE) and quality control (QC) techniques. Existing NDE and QC techniques are not optimized for AM processes, materials, or parts. Such lack of reliable means to verify and qualify AM parts is a significant barrier to further industrial adoption of AM technologies. Electromechanical impedance measurements have been recently introduced as an alternative solution to detect anomalies in AM parts. With this approach, piezoelectric wafers bonded to the part under test are utilized as collocated sensors and actuators. Due to the coupled electromechanical characteristics of piezoelectric materials, the measured electrical impedance of the piezoelectric wafer depends on the mechanical impedance of the part under test, allowing build defects to be detected. This paper investigates the effectiveness of impedance-based NDE approach to detect internal porosity in AM parts. This type of build defects is uniquely challenging as voids are normally embedded within the structure and filled with unhardened model or supporting material. The impact of internal voids on the electromechanical impedance of AM parts is studied at several frequency ranges.

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