A novel instrumented projectile for investigation of impact dynamics

Instrumented projectiles are widely used in the arena of military, geological studies, planetary and comet mission. Their applications in harsh environments call for a rugged and highly reliable system to ensure the survival of the internal electronics and reliable measurement of in situ data. These...

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Main Author: Pang, Xin
Other Authors: Du Hejun
Format: Theses and Dissertations
Language:English
Published: 2017
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Online Access:http://hdl.handle.net/10356/72232
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-722322023-03-11T17:45:34Z A novel instrumented projectile for investigation of impact dynamics Pang, Xin Du Hejun School of Mechanical and Aerospace Engineering DRNTU::Engineering Instrumented projectiles are widely used in the arena of military, geological studies, planetary and comet mission. Their applications in harsh environments call for a rugged and highly reliable system to ensure the survival of the internal electronics and reliable measurement of in situ data. These data are essential to study the various properties of the penetrated target and the projectile. The design, development and construction of a novel instrumented projectile for in situ deceleration measurement in high velocity impact conditions are presented in this thesis. A series of impact tests were performed using the developed instrumented projectile. The obtained acceleration responses from the series of tests, composed of transient, vibration and rigid-body responses were studied using frequency and frequency-time analysis to deduce the dominant resonance frequency of the instrumented projectile. Based on this deduction, optimum parameters for the design of the digital low-pass filtering schemes are obtained, which subsequently provides a consistent framework for the remaining studies in this work to extract the rigid-body deceleration of the instrumented projectile. The rigid body deceleration profile is important for examining the resistance of targets and verifying various prediction models. The novel instrumented projectile was employed to study the resistance characteristics of closed-cell aluminium foams of two different density groups and gauge lengths. The study shows that inertia effect has a larger influence on the rate sensitivity of the low density foams compared with the high density foams. This study also shows that the strain hardening behaviour of foam specimens and the normalised penetration depth are important factors that dictate the deceleration response profile of the projectile. The abovementioned factors are important to design an efficient energy absorber that controls the deceleration profile of a colliding mass. An analytical model is proposed to predict the responses of instrumented projectile when it is impacting on closed-cell aluminium foams. Predictions by the models are compared with experimental data and with the results obtained from three-dimensional finite element simulations. This proposed model is based on an exponential stress-strain relation that takes into consideration of the strain-hardening behaviour of the aluminium foam specimens. It was found that the proposed model gives a better prediction than another earlier model that is based on a Rigid Perfectly-Plastic Locking idealisation that dictates the foam’s resistance, which is only able to approximate the stress-strain characteristic of metal foams with low strain hardening. Doctor of Philosophy (MAE) 2017-05-30T03:41:56Z 2017-05-30T03:41:56Z 2017 Thesis Pang, X. (2017). A novel instrumented projectile for investigation of impact dynamics. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/72232 en 230 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering
spellingShingle DRNTU::Engineering
Pang, Xin
A novel instrumented projectile for investigation of impact dynamics
description Instrumented projectiles are widely used in the arena of military, geological studies, planetary and comet mission. Their applications in harsh environments call for a rugged and highly reliable system to ensure the survival of the internal electronics and reliable measurement of in situ data. These data are essential to study the various properties of the penetrated target and the projectile. The design, development and construction of a novel instrumented projectile for in situ deceleration measurement in high velocity impact conditions are presented in this thesis. A series of impact tests were performed using the developed instrumented projectile. The obtained acceleration responses from the series of tests, composed of transient, vibration and rigid-body responses were studied using frequency and frequency-time analysis to deduce the dominant resonance frequency of the instrumented projectile. Based on this deduction, optimum parameters for the design of the digital low-pass filtering schemes are obtained, which subsequently provides a consistent framework for the remaining studies in this work to extract the rigid-body deceleration of the instrumented projectile. The rigid body deceleration profile is important for examining the resistance of targets and verifying various prediction models. The novel instrumented projectile was employed to study the resistance characteristics of closed-cell aluminium foams of two different density groups and gauge lengths. The study shows that inertia effect has a larger influence on the rate sensitivity of the low density foams compared with the high density foams. This study also shows that the strain hardening behaviour of foam specimens and the normalised penetration depth are important factors that dictate the deceleration response profile of the projectile. The abovementioned factors are important to design an efficient energy absorber that controls the deceleration profile of a colliding mass. An analytical model is proposed to predict the responses of instrumented projectile when it is impacting on closed-cell aluminium foams. Predictions by the models are compared with experimental data and with the results obtained from three-dimensional finite element simulations. This proposed model is based on an exponential stress-strain relation that takes into consideration of the strain-hardening behaviour of the aluminium foam specimens. It was found that the proposed model gives a better prediction than another earlier model that is based on a Rigid Perfectly-Plastic Locking idealisation that dictates the foam’s resistance, which is only able to approximate the stress-strain characteristic of metal foams with low strain hardening.
author2 Du Hejun
author_facet Du Hejun
Pang, Xin
format Theses and Dissertations
author Pang, Xin
author_sort Pang, Xin
title A novel instrumented projectile for investigation of impact dynamics
title_short A novel instrumented projectile for investigation of impact dynamics
title_full A novel instrumented projectile for investigation of impact dynamics
title_fullStr A novel instrumented projectile for investigation of impact dynamics
title_full_unstemmed A novel instrumented projectile for investigation of impact dynamics
title_sort novel instrumented projectile for investigation of impact dynamics
publishDate 2017
url http://hdl.handle.net/10356/72232
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