Test cases for modeling and validation of structures with piezoelectric actuators
Download
1 / 19

Test Cases for Modeling and Validation of Structures with Piezoelectric Actuators - PowerPoint PPT Presentation


  • 118 Views
  • Uploaded on

Test Cases for Modeling and Validation of Structures with Piezoelectric Actuators. Mercedes C. Reaves and Lucas G. Horta Structural Dynamics Branch NASA Langley Research Center Hampton, Virginia Presented at the NASA Innovative Finite Element Solutions to Challenging Problems Workshop

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Test Cases for Modeling and Validation of Structures with Piezoelectric Actuators' - davis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Test cases for modeling and validation of structures with piezoelectric actuators

Test Cases for Modeling and Validation of Structures with Piezoelectric Actuators

Mercedes C. Reaves and Lucas G. Horta

Structural Dynamics Branch

NASA Langley Research Center

Hampton, Virginia

Presented at the NASA Innovative Finite Element Solutions to Challenging Problems Workshop

May 18, 2000 at NASA GSFC


Outline
Outline Piezoelectric Actuators

  • Objectives and background

  • Approach

  • Modeling methods

  • Aluminum beam testbed description/results

  • Composite beam testbed description/results

  • Concluding remarks


Objective
Objective Piezoelectric Actuators

Investigate and validate techniques for modeling structures with surface bonded piezoelectric actuators using commercially available FEM codes.


Approach
Approach Piezoelectric Actuators

  • Develop and validate FEM models of the following structures:

    • Aluminum beam testbed

    • Composite beam testbed

  • Study the following piezoelectric modeling approaches:

    • Piezoelectric effect via thermal analogy and Ritz vectors

    • Piezoelectric element using NASTRAN dummy element capability

    • ANSYS piezoelectric element


Modeling approaches
Modeling Approaches Piezoelectric Actuators

  • Thermal Strain Analogy

    • Induced strain using thermal load

    • 4-node composite quadrilateral element

    • Ritz vectors computed to capture local effect

  • MRJ piezoelectric elements implemented in User-Modifiable MSC/NASTRAN

    • Piezoelectric induced strains

    • Coupled field 4-node composite quadrilateral element

  • ANSYS

    • 3-D Coupled Field Solid element

    • Full harmonic analysis


Aluminum beam testbed
Aluminum Beam Testbed Piezoelectric Actuators

Aluminum

Beam

LaRC

Piezoelectric

Actuator


Aluminum beam testbed1
Aluminum Beam Testbed Piezoelectric Actuators

Actuator (3”x1.75”)

Strain gage

2.78”

3.625”

16”

Actuator

0.04”

Back to Back Strain gages


Instrumented aluminum beam
Instrumented Aluminum Beam Piezoelectric Actuators

Two strains gages

mounted back to back

Strain gages and Actuator

Proximity Probe


Aluminum beam analysis results
Aluminum Beam Analysis Results Piezoelectric Actuators

Mode 2

@ 31.8 Hz

Mode 1

@ 5.06 Hz

Mode 3

@ 57.6 Hz

Mode 4

@ 89.4 Hz


Composite box beam testbed
Composite Box Beam Testbed Piezoelectric Actuators

PZT actuator

0.5”

Strain gage

3.0”

PZT actuators

66 “

Beam cross section

(Outside dimensions)

0.75 ”

3.0 ”

laminate thickness = 0.03”

Material T300/976

laminate layout [45,-45,0]

s


Al beam correlation from various analysis codes
AL Beam Correlation from Various Analysis Codes Piezoelectric Actuators

Strain measurements versus Analysis Correlation

-5

10

Strain

in/in/volt

MRJ

Ritz

Test v-bond

ANSYS

-10

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)

200

100

Phase

(Degree)

0

-100

-200

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)


Al beam correlation from various analysis codes1
AL Beam Correlation from Various Analysis Codes Piezoelectric Actuators

Out of Plane Displacement Measurement versus Analysis Correlation

0

10

Tip

Displacement

in/volt

-5

10

MRJ-e116

Ritz-e116

Test v-bond

ANSYS

-10

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)

600

400

Phase

(Degree)

200

0

-200

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)


Results from thermal mapping test on al beam
Results from Thermal Mapping Test on AL Beam Piezoelectric Actuators

Possible

disbonds

Thermal mapping image of actuator

bonded to the aluminum beam


Comparison of actuator effectiveness on al beam

Bonding Technique Piezoelectric Actuators

v-bond- 14.5 psi, 24 hrs cure,

vacuum bag

p-bond- 1 psi, 24 hrs cure,

ambient

Comparison of Actuator Effectiveness on AL Beam

Strain Measurements

-5

10

Strain

in/in/volt

Test p-bond

Test v-bond

-10

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)

Displacement Measurements

0

10

Test p-bond

Test v-bond

Tip

Displacement

in/volt

-5

10

-10

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)


Instrumented composite box beam testbed
Instrumented Composite Piezoelectric ActuatorsBox Beam Testbed

Proximity

Probe

Beam

Strain

Gage

Actuators


Composite box beam analysis results
Composite Box Beam Analysis Results Piezoelectric Actuators

11.1 Hz

68.9 Hz

186.7 Hz

279.6 Hz


Box beam test versus analysis correlation
Box Beam Test versus Analysis Correlation Piezoelectric Actuators

Strain measurements versus Analysis Correlation

-5

10

Analysis

Test

-6

10

Strain

in/in/volt

-7

10

-8

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)

200

100

Phase

(Degree)

0

-100

-200

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)


Box beam test versus analysis correlation1
Box Beam Test versus Analysis Correlation Piezoelectric Actuators

Out of Plane Displacement Measurement versus Analysis Correlation

-2

10

Analysis

Test

-4

10

Tip

Displacement

in/volt

-6

10

-8

10

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)

600

400

Phase

(Degree)

200

0

-200

-1

0

1

2

3

10

10

10

10

10

Frequency (Hz)


Concluding remarks
Concluding Remarks Piezoelectric Actuators

  • Two testbeds developed and tested for validation of commercial analysis tools

  • Frequency response functions results using three different analysis approaches provided comparable test/analysis correlation

  • Low frequency resonance predicted within 5 and 13% but antiresonance showed errors of 16%

  • Improper bonding of actuators showed reductions in electrical to mechanical effectiveness of 64 %


ad