Use of Shock Tubes for Blast Testing

Volume 3A: Biomedical and Biotechnology Engineering ◽

10.1115/imece2013-63027 ◽

2013 ◽

Author(s):

Chong Whang ◽

Warren Chilton ◽

Philemon Chan

Keyword(s):

Shock Wave ◽

Shock Tube ◽

Laboratory Method ◽

Physical Models ◽

Test Model ◽

Shock Tubes ◽

Cfd Simulations ◽

Data Comparison ◽

Blast Overpressure ◽

Blast Testing

A computational fluid dynamics (CFD) study was carried out with data comparison to provide guidance for the control of open shock tube wave expansion to simulate field blast loadings for the conduct of biomechanical blast overpressure tests against surrogate test models. The technique involves the addition of a diffuser to the shock tube to prevent overexpansion before the shock wave impacts the test model. Mild traumatic brain injury (mTBI) has been identified as the signature injury for the conflicts in Iraq and Afghanistan, and blast overpressure from improvised explosive devices (IEDs) has been hypothesized as a significant mTBI risk factor. Research in the understanding of the mechanism of blast induced mTBI has been very active, which requires blast testing using animal and physical models. Full scale field blast testing is expensive. The use of shock tubes is clearly a viable cost effective laboratory method with many advantages. CFD simulations with data comparison show that without a diffuser, the shock wave exiting the tube tends to over expand producing an incident waveform with a short positive duration followed by a significant negative phase that is different from a Friedlander wave. However, the overexpansion effects can be mitigated by a diffuser. Shock tube tests also support the simulation results in which a diffuser improves the waveform from the shock tube. CFD simulations were validated by shock tube tests.

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INVESTIGATION OF PROCESSES IN THE HIGH-PRESSURE CHAMBER OF SHOCK TUBE

NONEQUILIBRIUM PROCESSES: RECENT ACCOMPLISHMENTS ◽

10.30826/nepcap9a-48 ◽

2020 ◽

Author(s):

N. G. Bykova ◽

◽

I. E. Zabelinsky ◽

P. V. Kozlov ◽

Yu. V. Tunik ◽

...

Keyword(s):

Shock Wave ◽

High Pressure ◽

Shock Tube ◽

High Energy ◽

Pressure Chamber ◽

High Pressure Chamber ◽

Shock Tubes ◽

The World

There are several installations with shock tubes in the world, in which a shock wave in air propagates at a speed close to the second cosmic one. Such velocities are achieved by supplying of high energy (~ 1 MJ) to the pushing gas in the high-pressure chamber.

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Blast Mitigation by Water Mist (2) Shock Wave Mitigation Using Glass Particles and Water Droplets in Shock Tubes

10.21236/ada411687 ◽

2003 ◽

Cited By ~ 3

Author(s):

Douglas Schwer ◽

K. Kailasanath

Keyword(s):

Shock Wave ◽

Water Mist ◽

Blast Mitigation ◽

Shock Tubes ◽

Water Droplets ◽

Shock Wave Mitigation

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Factors Contributing to Increased Blast Overpressure Inside Modern Ballistic Helmets

Applied Sciences ◽

10.3390/app10207193 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7193

Author(s):

Maciej Skotak ◽

Jonathan Salib ◽

Anthony Misistia ◽

Arturo Cardenas ◽

Eren Alay ◽

...

Keyword(s):

Experimental Study ◽

Shock Tube ◽

Principle Component Analysis ◽

Hot Spots ◽

Shape Factor ◽

Elevated Pressure ◽

Focal Points ◽

Parietal Region ◽

Blast Overpressure ◽

Pressure Fields

This study demonstrates the orientation and the "shape factor" have pronounced effects on the development of the localized pressure fields inside of the helmet. We used anatomically accurate headform to evaluate four modern combat helmets under blast loading conditions in the shock tube. The Advanced Combat Helmet (ACH) is used to capture the effect of the orientation on pressure under the helmet. The three modern combat helmets: Enhanced Combat Helmet (ECH), Ops-Core, and Airframe, were tested in frontal orientation to determine the effect of helmet geometry. Using the unhelmeted headform data as a reference, we characterized pressure distribution inside each helmet and identified pressure focal points. The nature of these localized “hot spots” is different than the elevated pressure in the parietal region of the headform under the helmet widely recognized as the under-wash effect also observed in our tests. It is the first experimental study which indicates that the helmet presence increased the pressure experienced by the eyes and the forehead (glabella). Pressure fingerprinting using an array of sensors combined with the application of principle component analysis (PCA) helped elucidate the subtle differences between helmets.

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Numerical estimations of lightning-induced mechanical damage in carbon/epoxy composites using shock wave overpressure and equivalent air blast overpressure

Composite Structures ◽

10.1016/j.compstruct.2019.111039 ◽

2019 ◽

Vol 224 ◽

pp. 111039 ◽

Cited By ~ 3

Author(s):

Juhyeong Lee ◽

Thomas E. Lacy ◽

Charles U. Pittman ◽

J.N. Reddy

Keyword(s):

Shock Wave ◽

Mechanical Damage ◽

Epoxy Composites ◽

Air Blast ◽

Blast Overpressure ◽

Numerical Estimations

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Effects of Wind on the Heat Flow of FPSO Topsides Subject to Fire: An Experimental and Numerical Study

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 2 ◽

10.1115/omae2010-20761 ◽

2010 ◽

Author(s):

Joon Young Yoon ◽

Seong Hwan Kim ◽

Gwon Cheol Yu ◽

Jung Kwan Seo ◽

Bong Ju Kim ◽

...

Keyword(s):

Thermal Diffusion ◽

Numerical Study ◽

Wind Tunnel Test ◽

Experimental Results ◽

Test Facility ◽

Test Model ◽

Cfd Simulations ◽

Fire Engineering ◽

Diffusion Characteristics ◽

Fire Loads

The aim of this paper is to examine the effect of wind on the thermal diffusion characteristics of floating production storage and offloading (FSPO) topside models subject to fire. It is motivated by the need to identify the fire loads on FPSO topsides, taking into account the effects of wind speed and direction. The results of an experimental and numerical study undertaken for these purposes are reported here. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. An experiment was performed on a 1/14-scale FPSO topside model using a wind tunnel test facility. The locations of the heat source of the fire were varied, as were the speed and direction of the wind, and the temperature distribution was measured. Computational fluid dynamics (CFD) simulations using the ANSYS CFX program were performed on the test model, with the results obtained compared with the experimental results. It is concluded that wind has a significant effect on the thermal diffusion characteristics of the test model and that the CFD simulations are in good agreement with the experimental results. The insights developed in this study will be very useful for the fire engineering of FPSO topsides.

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Numerical and Experimental Study of Turbulent Flows Around Clark Y-14 Aerofoil

Volume 7A: Fluids Engineering Systems and Technologies ◽

10.1115/imece2015-50536 ◽

2015 ◽

Author(s):

Kshitij Vadake ◽

Jie Cui

Keyword(s):

Fluid Dynamics ◽

Wind Tunnel ◽

Real World ◽

Force Measurement ◽

Test Model ◽

Wind Tunnel Testing ◽

Cfd Simulations ◽

Measurement Device ◽

Tunnel Testing

Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) have been instrumental in Fluid Mechanics to help solve scientific and engineering problems. This research attempts to use both techniques to perform a parametric study of turbulence flow around airfoil ClarkY-14 at various velocity and angle of attack (AoA). Clark Y-14 airfoil was designed in the 1920’s. It demonstrated good overall performance at low and moderate Reynolds numbers. With the progress in the aviation field, its performance was sub-optimal for newer aircraft designs. However, with the advent of RC airplanes and model aircrafts, there is a renewed interest in this airfoil. Various research projects have been conducted using this airfoil, but there hasn’t been a combined EFD and CFD study of the performance characteristics of the airfoil itself, which still finds real world applications today. One important aspect of this research included the investigation of the effects of a Force Measurement Device/Sensor, which is typically used in scaled/full-size wind tunnels to mount the test model as well as measure the forces/moments acting on it during the testing. The presence of such a device could affect the quality of the data obtained from the wind tunnel testing when compared to a real world application scenario where the aforementioned device may not be present. To the best of the author’s knowledge, no detailed study has been published on the effects of such devices. In this study, the results with and without the measuring device were generated by using CFD simulations. The results were then compared to see to what extent the inclusion of these devices will affect the results. The methodology used for this research was experimental as well as computational. In the present research, a commercially available CFD software STAR-CCM+ was employed to simulate the flows around airfoil Clark Y-14. The experimental data was obtained from wind tunnel tests using AEROLAB Educational Wind Tunnel (EWT) and compared with the simulation data from the CFD. The two data sets were in good agreement. Both experimental and simulation results were used to understand the effects of the measurement device/sensor used in the scaled wind tunnel on the lift and drag coefficients of the airfoil. Two separate CFD simulation setups were designed to model the presence and absence of the measurement device/sensor. These setups replicated the wind tunnel setup. The airfoil was tested and simulated at different speeds as well as different AoA. The comparative study gave a useful insight on the accuracy of the CFD simulations in relation to the actual testing. The analysis of results concluded that the force measurement device/sensor had insignificant effects on the accuracy and quality of data collected through wind tunnel testing.

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Shock Tube as an Impulsive Application Device

International Journal of Aerospace Engineering ◽

10.1155/2017/2010476 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Soumya Ranjan Nanda ◽

Sumit Agarwal ◽

Vinayak Kulkarni ◽

Niranjan Sahoo

Keyword(s):

Heat Transfer ◽

Shock Tube ◽

High Speed ◽

Force Measurement ◽

Peak Load ◽

Wave Force ◽

Impulsive Loading ◽

Force Balance ◽

Test Model ◽

Impulse Facility

Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.

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