Application of polyvinylidene fluoride for pressure measurements in an underwater explosion of aluminized explosives

One of the most challenging aspects when performing on-site piping troubleshooting is to obtain the most pertinent information possible regarding piping behavior: acceleration, stress, pressure levels, etc. This last parameter is always difficult to obtain because when pressure taps are available on the line, they are rarely in the area of interest. PVDF (PolyVinyliDene Fluoride) wire makes it possible to perform non-intrusive pressure measurements but needs to be calibrated in order to have a good representation of phenomenon occurring inside the pipe. After development of a dedicated calibrator and calculation of the fluid/structure coupling coefficient, VibraTec is able to assess PVDF sensor sensitivity according to client’s installation characteristics. Non-intrusive measurements provide a good accuracy regarding phenomenon amplitude and frequency localization even though some temperature restrictions apply to PVDF measurements. Although PVDF sensors seem to be simple to implement, particular attention must be paid during installation as this has a direct influence on the PVDF response.

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Pressure Measurements on a Deforming Surface in Response to an Underwater Explosion in a Water-Filled Aluminum Tube

Shock and Vibration ◽

10.1155/2001/146373 ◽

2001 ◽

Vol 8 (1) ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

G. Chambers ◽

H. Sandusky ◽

F. Zerilli ◽

K. Rye ◽

R. Tussing ◽

...

Keyword(s):

Shock Loading ◽

Tube Wall ◽

Underwater Explosion ◽

Computer Code ◽

Dynamic Interaction ◽

Hypodermic Needle ◽

Pressure Measurements ◽

Cylindrical Structures ◽

Explosive Charges ◽

Carbon Resistor

Experiments have been conducted to benchmark DYSMAS computer code calculations for the dynamic interaction of water with cylindrical structures. Small explosive charges were suspended using hypodermic needle tubing inside Al tubes filled with distilled water. Pressures were measured during shock loading by tourmaline crystal, carbon resistor and ytterbium foil gages bonded to the tube using a variety of adhesives. Comparable calculated and measured pressures were obtained for the explosive charges used, with some gages surviving long enough to record results after cavitation with the tube wall.

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Pressure measurements on a deforming surface in response to an underwater explosion

10.1063/1.55492 ◽

1998 ◽

Author(s):

G. Chambers ◽

H. Sandusky ◽

F. Zerilli ◽

K. Rye ◽

R. Tussing

Keyword(s):

Underwater Explosion ◽

Pressure Measurements

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Ice Pressure Measurements Using PVDF Film

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.2919841 ◽

1990 ◽

Vol 112 (1) ◽

pp. 91-95

Author(s):

A. Joensuu

Keyword(s):

Polyvinylidene Fluoride ◽

Mechanical Deformation ◽

Pvdf Film ◽

Pressure Measurements ◽

Measuring Devices ◽

Contact Surfaces ◽

Ice Pressure ◽

Complicated Geometries ◽

Shed Light ◽

Signal Treatment

Piezoelectric ice pressure measuring devices have been constructed using polyvinylidene fluoride (PVDF) film. PVDF seems to be an appealing transducer material since it is light, thin, mechanically resistant and can be attached on surfaces with complicated geometries. Moreover, it is commercially available in large sheets. Dynamic ice pressure distribution can be monitored using various metalization patterns thus dividing the areas into many active cells. Because minimum mechanical deformation is needed for the piezoelectric phenomenon to take place, the device does not interfere with the quantity to be measured. It is believed that the material will help to shed light on the ice pressure formation process in crushing. The paper deals with full-scale experiments conducted using PVDF film on the contact surfaces of a test hammer and a cylindrical indentor, and describes the signal treatment used.

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Signal Interpretation Considerations When Estimating Subglottal Pressure From Oral Air Pressure

Journal of Speech Language and Hearing Research ◽

10.1044/2018_jslhr-s-17-0432 ◽

2019 ◽

Vol 62 (5) ◽

pp. 1326-1337 ◽

Cited By ~ 2

Author(s):

Brittany L. Perrine ◽

Ronald C. Scherer ◽

Jason A. Whitfield

Keyword(s):

Standard Condition ◽

Word Production ◽

Air Pressure ◽

Pressure Waveform ◽

Pressure Measurements ◽

Air Leak ◽

Pressure Signal ◽

Adult Participants ◽

Syllable Repetition ◽

Subglottal Pressure

Purpose Oral air pressure measurements during lip occlusion for /pVpV/ syllable strings are used to estimate subglottal pressure during the vowel. Accuracy of this method relies on smoothly produced syllable repetitions. The purpose of this study was to investigate the oral air pressure waveform during the /p/ lip occlusions and propose physiological explanations for nonflat shapes. Method Ten adult participants were trained to produce the “standard condition” and were instructed to produce nonstandard tasks. Results from 8 participants are included. The standard condition required participants to produce /pːiːpːiː.../ syllables smoothly at approximately 1.5 syllables/s. The nonstandard tasks included an air leak between the lips, faster syllable repetition rates, an initial voiced consonant, and 2-syllable word productions. Results Eleven oral air pressure waveform shapes were identified during the lip occlusions, and plausible physiological explanations for each shape are provided based on the tasks in which they occurred. Training the use of the standard condition, the initial voice consonant condition, and the 2-syllable word production increased the likelihood of rectangular oral air pressure waveform shapes. Increasing the rate beyond 1.5 syllables/s improved the probability of producing rectangular oral air pressure signal shapes in some participants. Conclusions Visual and verbal feedback improved the likelihood of producing rectangular oral air pressure signal shapes. The physiological explanations of variations in the oral air pressure waveform shape may provide direction to the clinician or researcher when providing feedback to increase the accuracy of estimating subglottal pressure from oral air pressure.

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