STUDY OF CUTTING AERIAL PMMA WITH MINIATURE DETONATION CORD

In order to shorten the time of through-the-canopy-ejection, and to ensure pilot safely escape and survive. The application of linear cutting technique using miniature detonation cord( MDC) in through-the-canopy-ejection-system is proposed. A series of different kinds of MDC are designed. Firstly experimental study on the cutting process of the PMMA plate wiht MDC is carried out. Material of metal cover explosive types and the range of charge quantities are determined. Consequently the phenomena of spallation is observed, and the relationship between the cutting depth and charge quantities is obtained. For the comparison, the process of explosion cutting PMMA plate is simulated by means of nonlinear dynamic analysis code LS-DYNA. Spallation phenomena which occurs in the experiment, is also observed in the simulation. Simulation results present the relationship of cutting depth of PMMA plate versus charge linear density, which well agree with experimental ones.

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Nonlinear Dynamic Analysis of Disordered Voice: The Relationship Between the Correlation Dimension (D2) and Pre-/Post-Treatment Change in Perceived Dysphonia Severity

Journal of Voice ◽

10.1016/j.jvoice.2008.11.003 ◽

2010 ◽

Vol 24 (3) ◽

pp. 285-293 ◽

Cited By ~ 20

Author(s):

Shaheen N. Awan ◽

Nelson Roy ◽

Jack J. Jiang

Keyword(s):

Dynamic Analysis ◽

Nonlinear Dynamic ◽

Correlation Dimension ◽

Nonlinear Dynamic Analysis ◽

Post Treatment ◽

Treatment Change ◽

The Relationship

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Nonlinear Dynamic Analysis of the Cutting Process of a Nonextensible Composite Boring Bar

Shock and Vibration ◽

10.1155/2020/5971540 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Bole Ma ◽

Yongsheng Ren

Keyword(s):

Differential Equation ◽

Dynamic Analysis ◽

Cutting Force ◽

Nonlinear Dynamic ◽

Nonlinear Dynamic Analysis ◽

Primary Resonance ◽

Cutting Process ◽

Cutting Depth ◽

Resonance Curves ◽

Cutting System

A nonlinear dynamic analysis of the cutting process of a nonextensible composite cutting bar is presented. The cutting bar is simplified as a cantilever with plane bending. The nonlinearity is mainly originated from the nonextensible assumption, and the material of cutting bar is assumed to be viscoelastic composite, which is described by the Kelvin–Voigt equation. The motion equation of nonlinear chatter of the cutting system is derived based on the Hamilton principle. The partial differential equation of motion is discretized using the Galerkin method to obtain a 1-dof nonlinear ordinary differential equation in a generalized coordinate system. The steady forced response of the cutting system under periodically varying cutting force is approximately solved by the multiscale method. Meanwhile, the effects of parameters such as the geometry of the cutting bar (including length and diameter), damping, the cutting coefficient, the cutting depth, the number of the cutting teeth, the amplitude of the cutting force, and the ply angle on nonlinear lobes and primary resonance curves during the cutting process are investigated using numerical calculations. The results demonstrate that the critical cutting depth is inversely proportional to the aspect ratio of the cutting bar and the cutting force coefficient. Meanwhile, the chatter stability in the milling process can be significantly enhanced by increasing the structural damping. The peak of the primary resonance curve is bent toward the right side. Due to the cubic nonlinearity in the cutting system, primary resonance curves show the characteristics of typical Duffing’s vibrator with hard spring, and jump and multivalue regions appear.

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