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- Energetic materials (2)
- Defects (1)
- Explosives (1)
- Human pilot model (1)
- Inhomogeneous waves (1)
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- Lateral stability (1)
- Least-squares reconstruction (1)
- Localized heating (1)
- Metamaterials (1)
- Nonlinear dynamics (1)
- Ordering Effects (1)
- Periodic structures (1)
- Psychoacoustics (1)
- Stability analysis (1)
- Stress concentrations (1)
- Thermomechanics (1)
- Transfer Bias (1)
- Vehicle dynamics (1)
- Vibration (1)
- Viscoelastic materials (1)
Articles 1 - 5 of 5
Full-Text Articles in Mechanical Engineering
Generation Of Inhomogeneous Acoustic Waves Using An Array Of Loudspeakers, Samuel E. Wonfor, Trevor A. Kyle, J. Stuart Bolton, Jeffrey F. Rhoads
Generation Of Inhomogeneous Acoustic Waves Using An Array Of Loudspeakers, Samuel E. Wonfor, Trevor A. Kyle, J. Stuart Bolton, Jeffrey F. Rhoads
The Summer Undergraduate Research Fellowship (SURF) Symposium
In previous studies it has been shown that pressure fields created by inhomogeneous sound waves (waves which decay in a direction perpendicular to their propagation direction) are able to transmit energy into objects more effectively than ones created by conventional sound waves. This behavior may be useful in the detection of hidden explosive threats. To explore this, a device capable of constructing inhomogeneous waves is being developed. The proposed device is an acoustic array consisting of several high-frequency speakers. The speakers are independently driven to construct a desired inhomogeneous pressure field on a target surface. Inhomogeneous pressure fields were reconstructed …
Examination Of Ordering Effects In Sound Evaluations, Yiyun Zhang, Patricia Davies, Daniel Carr
Examination Of Ordering Effects In Sound Evaluations, Yiyun Zhang, Patricia Davies, Daniel Carr
The Summer Undergraduate Research Fellowship (SURF) Symposium
It is difficult to predict sound annoyance responses because annoyance is an inherently subjective concept and the evaluation standard could be different from each person. Usually, annoyance models are functions of strengths of sound characteristics only, and these models can help engineers to improve sounds that machines make and minimize annoyance levels, but other factors can also influence annoyance ratings of products. The main goal of this research was to investigate ordering effects in sound evaluations when people are hearing a set of sounds in sequence. Of particular interest is how the response to a sound influences the response to …
Stability Analysis Of A Flexible Vehicle Model Controlled By Human Pilot Models, Abhishek Ajmani, Anil Bajaj
Stability Analysis Of A Flexible Vehicle Model Controlled By Human Pilot Models, Abhishek Ajmani, Anil Bajaj
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a constant race among automobile manufactures to design safer vehicles while minimizing weight to reduce power consumption. Additionally, organizations like NASA and SpaceX are persistently working toward creating reliable, lightweight rovers to be used on the surface of Mars. However, the lightweight requirement often increases vehicle flexibility, which further develops a tendency toward instability in the lateral (sideways) direction. This investigation develops a mathematical model that represents the dynamics of a flexible vehicle in forward motion, and a heuristic human pilot model is proposed which controls the vehicle. Following such formulation, the combined vehicle and pilot model is …
The Influence Of Macroscale Stress Concentrations On The Near-Resonant Thermomechanics Of Mock Energetic Materials, Lauren A. Cooper, Allison R. Range, Jeffrey F. Rhoads
The Influence Of Macroscale Stress Concentrations On The Near-Resonant Thermomechanics Of Mock Energetic Materials, Lauren A. Cooper, Allison R. Range, Jeffrey F. Rhoads
The Summer Undergraduate Research Fellowship (SURF) Symposium
The characterization of particulate composite energetic materials, both with and without stress concentration, is currently of great interest to the defense community. This work seeks to further characterize the self-heating effect of composite energetic plates, particularly around regions of high stress, when subjected to harmonic excitation near resonance. Mock energetic plates with macroscale stress concentrations are prepared in various compositions based on the PBXN-109 formulation, and are tested near the first resonant frequency using an electrodynamic shaker. The resulting mechanical and thermal responses are recorded using a laser Doppler vibrometer and an infrared camera, respectively. Upon comparison between the regions …
Dynamic Characterization Of Periodic Lattice Of Elastically-Connected Bi-Stable Elements Under Seismic Excitation, Lingwei Meng, Myungwon Hwang, Andres F. Arrieta Ph.D.
Dynamic Characterization Of Periodic Lattice Of Elastically-Connected Bi-Stable Elements Under Seismic Excitation, Lingwei Meng, Myungwon Hwang, Andres F. Arrieta Ph.D.
The Summer Undergraduate Research Fellowship (SURF) Symposium
Metamaterials are engineered materials, typically in periodic arrangements, which exhibit unconventional or extreme properties not found in nature. Understanding the dynamics of metamaterials enables the design of structures with specific functionalities. The dynamics of metamaterials in linear regime has been relatively well studied in recent years, however the unique phenomena arising from nonlinearities in metamaterials are yet to be explored. In this paper, we focus on an array of bi-stable elements connected by elastic springs under various forms of external excitations acting on the entire system. The general equations of motion are derived to handle any degree-of-freedom (DoF) systems of …