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Pyrotechnic shock or pyroshock is the transient motion of structural elements, assemblies, subsystems, or systems due to explosive loading induced by the detonation of ordnance devices incorporated into or attached to the structure. Pyroshock is often characterized by its high peak acceleration (300 g to 300 kg), high frequency content (100 Hz to 1 MHZ) and short duration (10 µsec to 20 msec), which is largely dependent on the source type and strength, structural type and configuration, and especially the distance from the source to the response point of interest. For aerospace applications, explosive devices are generally used to separate structural subsystems (e.g., payloads from launch vehicles), deploy appendages (e.g., solar panels), or activate on-board operational subsystems (e.g., propellant valves) [Ref. 1,2]. In certain cases, the explosive loading may be accompanied by the release of stored energy due to structural preload. Current spacecraft design often utilizes numerous explosive devices over the course of a mission.

The information contained in this document is the property of Endevco Corporation and is confidential and/or copyright material.  This information and this document may not be used without the express authorization of Endevco. Any unauthorized use or disclosure may be unlawful.

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What Endevco has to offer for shock sensors

Features Description of the 7270A 2K, 6K, 20K, 60K and 200K g full range High resonant frequency DC response Rugged undamped Negligible zero shift after shock

The ENDEVCO® Model 7270A is a family of rugged undamped piezoresistive accelerometers designed for High Shock measurements

Mainly used for High Shock testing in labs, and test sites.

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What Endevco has to offer for shock sensors

Features Description Model 71 6K, 20K, and 60K g full range High resonant frequency DC response Rugged undamped Negligible zero shift after shock 0.06 gram weight

The Endevco® model 71 series of subminiature SMT piezoresistive accelerometers are rugged undamped accelerometers designed for shock measurements.

Mainly used for High Shock testing for on-board

Applications.

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What Endevco has to offer for shock sensors

Features Description 2250A ± 500 g full range High resonant frequency Wide Band width 0.4 gram weight

The ENDEVCO® Model 2250AM1 is an extremely small, adhesively mounted

piezoelectric accelerometer with integral electronics.This accelerometer offers high resonance frequency and wide bandwidth.Designed specifically for measuring

vibration in mini-structures and small objects.

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What Endevco has to offer for shock sensors

Features Description 7255A 5K, 25K, 50K g full range Low impedance output Built-in mechanical filter Hermetically sealed 5.0 gram weight

The ENDEVCO® Model 7255A-XX PYROTRON is a miniature, light weight piezoelectric accelerometer. The unit incorporates a uniquely designed built-in mechanical filter system to effectively block out high frequency energy, protecting the sensing element from overstress.Designed specifically for near-field pyroshock and high-level mechanical impact measurements due to its 300,000 g survivability.

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What Endevco has to offer for shock sensors

Features Description 2255B ± 5,000 to ± 50,000 g full range Low impedance output Far-field, high-g shock Built-in electronic LP filter Strain isolated Solder terminals 2.0 gram weight

The Endevco® Model 2255B is a miniature, lightweight piezoelectric accelerometer with integral electronics.The unit features an electronic second order low-pass filter between the sensor and the amplifier input stage to prevent saturation due to accelerometer resonance.Designed specifically for far-field high-g shock measurement on structures and test articles.

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What Endevco has to offer for shock sensors

Features Description 2225M5A 20,000 to 100,000 g full range High-g shock Industry Standard Rugged - requires no external power Annular shear 13.0 gram weight

The Endevco® models 2225 and 2225M5A are lightweight piezoelectric accelerometers

The model 2225 features a 10-32 threaded hole, while the model 2225M5A features a 1/4-28 threaded hole for additional mounting integrity needed during high-g shock.

Designed specifically for measuring high-g shock on structures and test articles.

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What Endevco has to offer for shock sensors

Features Description 7264C and D 500 g and 2000 g Full Scale Ranges Mechanical Overtravel Stops Small Size, Rugged DC Response - Long Duration Transients 1.0 gram weight

The ENDEVCO Model 7264C/D is a very low mass piezoresistive accelerometer weighing only 1 gram.

This accelerometer meets SAEJ211 specifications for anthropomorphic dummy instrumentation.

Designed for crash testing, flutter testing, rough road testing and similar applications that require minimal mass loading and a broad frequency response.

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Near-field within 6 inches of source materials stress waves dominate response peak accelerations greater than 5000 g’s and contains frequency content up to and

above 1 MHz very difficult to measure due to instrumentation limitations

Mid-field 6–24 inches from source peak accelerations greater than 1000 g’s and contains frequency content up to and

above 10 KHz

Far-field greater than 24 inches from source low g levels and frequencies usually less than 10KHz

Characteristics of pyroshock vary greatly with distance from shock event

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How do you test these sensors??

Model 2925 Pneumatically Operated Projectile (POP) The ENDEVCO® Model 2925 POP provides an accurate

controlled means of shock sensitivity calibration of accelerometers. The POP is designed to be used with the Model 2270 family of back-to-back comparison calibration standard accelerometers.

Calibrations are performed at accelerations from 400g to well above 10,000g at half-sine pulse durations from 3 ms to 100 µs.

The system can be used manually in a stand-alone mode, or in a fully computer controlled mode

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How do you test these sensors??

Hopkinson Bar Provides extremely high g levels A controlled projectile impacts the end of a metallic bar, and a stress wave of

know magnitude propagates through the bar. UUT is at end of bar and experiences high g rapid rise time stress when wave

arrives Also used in calibration of accelerometers Exotic materials such as Beryllium and

Titanium are sometimes used for

Hopkinson Bars

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Pyrotechnic Shock (http://www.vibrationdata.com/SRS.htm )NASA Pyrotechnic Shock Design Guidelines Manual: NasaPyro.zip

By Kacena, McGrath, and Rader.

Martin Marrietta, Joint & Distance Attenuation: mm_shock.pdfNASA Pyroshock Test Criteria, by D. Kern: NASA-HDBK-7003Measuring and Analysis of Pyrotechnic Shock: pyroshoc.pdf

Submitted by John Eriksson and Mattias Hansson, Chalmers University of Technology, Sweden. Vibrationdata.com student paper contest, Spring 2000.

Pyroshock Data Acquistion and Analysis for U/RGM-109D Payload Cover Ejection Tests, NWC TP 6927, By Allan Piersol: Pyro_Data_AQ.pdf

Pyrotechnic Shock Flight Failures: Moening.pdfBy C.J. Moening

Gaberson and Chalmers, Modal Velocity as a Criterion of Shock Severity, Shock and Vibration Bulletin, Naval Research Lab, December 1969: modal_velocity.pdfMIL-STD-810F, Method 517 Pyroshock: MIL810F_pyroshock.pdfThe Proposed NASA Pyroshock Test Criteria Standard: NASA_pyro2.pdf

Mechanical Shock from Frangible Joints, by V.R. Paul: frangible_joints.pdfPyrotechnic Shock Structural Response, by R.G. Merritt: Merritt.pdfV-Band Separation Shock Characteristics, by K.Y. Chang: V_Band.pdf

Pyrotechnic Shock Simulation in the Test LabHigh G Pyrotechnic Shock Simulation Using Metal-to-Metal Impact: Bai.pdf

By Monty Bai and Wesley ThatcherThe Controlled Response of Resonating Fixtures Used to Simulate Pyroshock Enviroments, by Neil Davie:

resonating_fixture.pdfSummary of Testing Techniques, by Dan Powers: Powers_test.pdfMulti-Degree-of-Freedom Pyrotechnic Shock Simulation, Slide Presentation, by Smith and Hollowell: mdof_sim.pdfComparison of Response from Different Resonant Plate Simulation Techniques: Morse_test.pdfHigh Frequency Mechanical Pyroshock Simulation for Payload Systems, by Bateman, et al: payload_SRS.pdfPyrotechnic Shock Testing: Pyrotechnic Shock Testing: Real Test Lab Experiences at EBA&D, by Keon (slide presentation):

EnsignBickford.pdf

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Confidentiality agreement

The information contained in this document is the property of Endevco Corporation and is confidential and/or copyright material.  This information and this document may not be used or disclosed without the express authorization of Endevco.  Any unauthorized use or disclosure may be unlawful.  The information contained in this document may be subject to the provisions of the Export Administration Act of 1979 (50 USC 2401-2420), the Export Administration Regulations promulgated there under (15 CFR 730-744), and the International Traffic in Arms Regulations (22 CFR 120-130).  The recipient acknowledges that these statutes and regulations impose restrictions on import, export, re-export and transfer to third countries of certain categories of data, technical services and information, and that licenses from the US Department of State and/or the US Department of Commerce may be required before such data, technical services and information can be disclosed.  By accepting this document, the recipient agrees to comply with all applicable governmental regulations as they relate to the import, export and re-export of information.