MECHANICAL ENGINEERING

Structural Dynamics

Most engineering structures are designed to withstand some form of dynamic loading, whether it results from a seismic event, sustained high-wind loadings, other highly energetic forms such as blast loadings, or normal vibrations. Knowledge of the structural response to these events is crucial in designing a structure that maintains both the strength and flexibility under service. GNNA provides technical expertise in addressing design and analysis of structures subjected to dynamic environments, through application of theoretical, analytical, and computational methods.

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Hydrodynamics

Hydrodynamics encompasses theoretical, analytical, and numerical solutions of material behavior undergoing extremely high deformations at very high strain-rates, such high-explosive (HE) blast, gaseous detonation events and high-velocity impact and penetration. Tightly coupled with hydrodynamics are the foundational principles of shock-physics, for example applying impedance-matching techniques to complex shock and impact problems. GNNA utilizes state-of-the-art analyses tools to solve some highly complex engineering problems not readily amenable to theoretical or analytical methods. Below are samplings of typical engineering design and analysis problems requiring utilization of numerical (i.e. computational) hydrodynamics methods.

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Fracture Mechanics

Rarely are structural materials defect-free, either from the manufacturing process or from normal environmental effects. Furthermore, under repeated cyclic static or dynamic loadings, materials develop flaws, limiting their useful life. Fatigue analysis thus provides one measure of the useful life until onset of crack-initiation, which is applied in most designs. Yet structures with known flaws are capable to maintain service life for extended periods beyond crack-initiation. Fracture mechanics provides a means to assess conditions when a flaw may become unstable and thereby remove the part or structure from service. GNNA has developed a practical experience base in solving fatigue and fracture problems through application of conventional linear-elastic and elastic-plastic fracture mechanics, as well as computational.

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Pressure Vessel Design

GNNA has over 30-years experience with design and analysis of pressure vessels in accordance with the ASME Boiler and Pressure Vessel Code. Active participation is maintained with Section III, Nuclear Vessels and Section VIII, Division 3, High-Pressure Vessels, through membership in Code Committees that develop technical guidance. GNNA principals in conjunction with the ASME Section VIII, Division 3, Task Group on Impulsively Loaded Vessels, have developed design rules for vessels subjected to highly impulsive loadings, such as HE blast or gaseous detonations.

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