USH336H - Non-destructive method to assess physical condition of chemical fill - Google Patents

Non-destructive method to assess physical condition of chemical fill Download PDF

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Publication number
USH336H
USH336H US06/937,802 US93780286A USH336H US H336 H USH336 H US H336H US 93780286 A US93780286 A US 93780286A US H336 H USH336 H US H336H
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United States
Prior art keywords
projectile
fill
condition
vibrations
liquid fill
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Abandoned
Application number
US06/937,802
Inventor
Miles C. Miller
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US Department of Army
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US Department of Army
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
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Priority to US06/937,802 priority Critical patent/USH336H/en
Assigned to ARMY, THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE reassignment ARMY, THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MILLER, MILES C.
Application granted granted Critical
Publication of USH336H publication Critical patent/USH336H/en
Abandoned legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
    • G01N9/02—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume
    • G01N9/04—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring weight of a known volume of fluids

Definitions

  • Chemical projectiles often include a payload consisting of a liquid fill, for example, nerve agent, mustard, or white phosphorous. After long term storage, these fills may undergo a chemical or physical change in their physical properties such as density, viscosity, etc. which can affect their performance, functioning and military potential.
  • a liquid fill for example, nerve agent, mustard, or white phosphorous.
  • these fills may undergo a chemical or physical change in their physical properties such as density, viscosity, etc. which can affect their performance, functioning and military potential.
  • the instant invention is a method by which the condition of the liquid fill in a projectile can be assessed without requiring cutting, drilling, and/or altering the structure of the shell or payload.
  • This non-destructive technique can be used with projectiles filled with toxic or hazardous materials and can occur within the confines of storage buildings.
  • Another object of this invention is to provide a system which determines the condition of the liquid fill in a projectile without requiring alteration of the shell structure or payload.
  • FIG. 1 is a view of an embodiment of a system incorporating a method for assessment of the condition of liquid fill in a projectile without alteration of the shell structure or payload;
  • FIG. 2 is a perspective view in three dimensions of graphs of a typical test liquid fill indicating the relationship between wave amplitude, frequency, damping, viscosity and time for the invention.
  • FIGS. 1 and 2 of the drawings there is a testing system shown embodying the principles of this invention.
  • the embodiment of the invention is based on measuring the frequency and damping characteristics of a projectile 10 and liquid fill (not shown) at their natural vibrational response conditions.
  • FIG. 1 An actual projectile 10 is suspended in the air by an elastic cable 12 so that the projectile 10 is free to vibrate.
  • An accelerometer 14 is placed on the outside surface of the projectile 10, either on the base or side.
  • the projectile 10 is then struck with a mallet 16 or other heavy object to cause the projectile 10 and liquid fill (not shown) to vibrate at their natural frequencies.
  • the accelerometer 14 and recording and storage oscilloscope 18 will detect and record the amplitude and frequency of the projectile and fill motion resulting from this impact as a function of time.
  • vibration frequencies will be observed which include responses from all the excited parts including the projectile casing components and fill.
  • This data is then input into a spectral analyzer 20 which produces a plot of the amplitude as a function of frequency and time as depicted in FIG. 2 allowing each of the vibrational elements, including the liquid fill, to be isolated and their respective contributions evaluated.
  • the density of the liquid fill will influence the frequency 21 and the viscosity of the liquid fill will influence the amplitude decay 22 with time (i.e., damping) of the signals obtained.
  • This data can be compared to a standard reference projectile 10 and liquid fill or can be based on previous calibrations using a series of projectiles and various fills having different densities and viscosities.
  • the frequency 21 and amplitude decay (damping) 22 represent two different and independent parameters which could provide a unique signature to differentiate between the relative density and viscosity of the liquid fills.
  • the apparatus can be used in the confines of the storage area and does not require destruction of the projectile 10 or involve a hazardous operation.
  • This method is independent of whether the liquid fill is homogeneous or has a non-homogeneous or stratified composition and is unaffected by the presence of baffles or other non-rigid or rigid elements within the projectile.
  • this invention provides for assessment of the liquid fill in the presence of configurations intended to improve the munition effectiveness or disguise the presence of its liquid fill in a manner which would prevent determination by other techniques.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

This invention relates to a method for assessment of the condition, and cge of condition, of the liquid fill for chemical projectiles by analyzing the vibrational characteristics of the projectile and fill. It is a method by which the condition of the liquid fill in a projectile can be assessed without requiring cutting, drilling, and/or altering the structure of the shell or payload. This non-destructive technique can be used with projectiles filled with toxic or hazardous materials and can occur within the confines of storage buildings. The system for incorporating the method of the invention includes a projectile which is freely suspended and then struck with a device causing the projectile and the fill to vibrate. The natural vibrational characteristics of the projectile and fill are measured and recorded and can be compared to model data to ascertain any changes in the physical characteristics of the fill.

Description

GOVERNMENT INTEREST
The invention described herein may be manufactured used and licensed by or for the Government for Governmental purposes without the payment to me of any royalties thereon.
BACKGROUND AND SUMMARY OF THE INVENTION
Chemical projectiles often include a payload consisting of a liquid fill, for example, nerve agent, mustard, or white phosphorous. After long term storage, these fills may undergo a chemical or physical change in their physical properties such as density, viscosity, etc. which can affect their performance, functioning and military potential.
The instant invention is a method by which the condition of the liquid fill in a projectile can be assessed without requiring cutting, drilling, and/or altering the structure of the shell or payload. This non-destructive technique can be used with projectiles filled with toxic or hazardous materials and can occur within the confines of storage buildings.
It is an object of this invention, therefore, to provide a system for ascertaining the condition of the liquid fill in a projectile.
Another object of this invention is to provide a system which determines the condition of the liquid fill in a projectile without requiring alteration of the shell structure or payload.
It is another object of this invention to provide a system for liquid fill assessment of a projectile which can take place within the projectile storage area without requiring the projectile to be removed from the storage building.
Further objects and advantages of this invention will become more apparent in light of the following drawings and description of the preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of an embodiment of a system incorporating a method for assessment of the condition of liquid fill in a projectile without alteration of the shell structure or payload; and
FIG. 2 is a perspective view in three dimensions of graphs of a typical test liquid fill indicating the relationship between wave amplitude, frequency, damping, viscosity and time for the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Referring to FIGS. 1 and 2 of the drawings, there is a testing system shown embodying the principles of this invention. The embodiment of the invention is based on measuring the frequency and damping characteristics of a projectile 10 and liquid fill (not shown) at their natural vibrational response conditions.
The test item and associated instrumentation are illustrated in FIG. 1. An actual projectile 10 is suspended in the air by an elastic cable 12 so that the projectile 10 is free to vibrate. An accelerometer 14 is placed on the outside surface of the projectile 10, either on the base or side.
The projectile 10 is then struck with a mallet 16 or other heavy object to cause the projectile 10 and liquid fill (not shown) to vibrate at their natural frequencies. The accelerometer 14 and recording and storage oscilloscope 18 will detect and record the amplitude and frequency of the projectile and fill motion resulting from this impact as a function of time.
A multitude of vibration frequencies will be observed which include responses from all the excited parts including the projectile casing components and fill. This data is then input into a spectral analyzer 20 which produces a plot of the amplitude as a function of frequency and time as depicted in FIG. 2 allowing each of the vibrational elements, including the liquid fill, to be isolated and their respective contributions evaluated.
The density of the liquid fill will influence the frequency 21 and the viscosity of the liquid fill will influence the amplitude decay 22 with time (i.e., damping) of the signals obtained. This data can be compared to a standard reference projectile 10 and liquid fill or can be based on previous calibrations using a series of projectiles and various fills having different densities and viscosities.
An extension of this free vibration method would be to employ a forced vibration method, but this might act to alter the fluid properties. The frequency 21 and amplitude decay (damping) 22 represent two different and independent parameters which could provide a unique signature to differentiate between the relative density and viscosity of the liquid fills.
The apparatus can be used in the confines of the storage area and does not require destruction of the projectile 10 or involve a hazardous operation.
This method is independent of whether the liquid fill is homogeneous or has a non-homogeneous or stratified composition and is unaffected by the presence of baffles or other non-rigid or rigid elements within the projectile. Thus, this invention provides for assessment of the liquid fill in the presence of configurations intended to improve the munition effectiveness or disguise the presence of its liquid fill in a manner which would prevent determination by other techniques.
Accordingly, modifications and variations to which the invention is susceptible may be practiced without departing from the scope and intent of the appended claims.

Claims (3)

What is claimed is:
1. A method for noninvasively assessing the condition of liquid fill within a sealed projectile by measuring the frequency and damping characteristics of the said fill through its natural vibrational response conditions upon excitation, comprising the steps of:
suspending said projectile from an elastic cable means;
striking said projectile with an object to cause vibration;
measuring the vibrational pattern of said projectile, which vibration includes a composite of both fill vibration and projectile vibrations at their respective natural frequencies; and
analyzing said responses to determine a change in fill vibrational response against known standards, to determine present condition of said fill thereby.
2. The method of claim 1 wherein the said measuring step comprises attaching an accelerometer means to the body of said projectile, which accelerometer means transduces mechanical projectile vibrations into electrical signals, feeding said accelerometer's electrical signals into an oscilloscope and spectral analyzer arrangement, whereby vibrations of said projectile and fill may be thereby analyzed.
3. The method of claim 2 wherein said object for striking the projectile is a hand mallet.
US06/937,802 1986-12-04 1986-12-04 Non-destructive method to assess physical condition of chemical fill Abandoned USH336H (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US06/937,802 USH336H (en) 1986-12-04 1986-12-04 Non-destructive method to assess physical condition of chemical fill

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US06/937,802 USH336H (en) 1986-12-04 1986-12-04 Non-destructive method to assess physical condition of chemical fill

Publications (1)

Publication Number Publication Date
USH336H true USH336H (en) 1987-10-06

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US06/937,802 Abandoned USH336H (en) 1986-12-04 1986-12-04 Non-destructive method to assess physical condition of chemical fill

Country Status (1)

Country Link
US (1) USH336H (en)

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AS Assignment

Owner name: ARMY, THE UNITED STATES OF AMERICA AS REPRESENTED

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MILLER, MILES C.;REEL/FRAME:004686/0973

Effective date: 19871126

STCF Information on status: patent grant

Free format text: PATENTED CASE