Elastic instabilities in polymer tube of resonant sound absorbers under hydrostatic pressure

The solution of the problem of hydrostatic compression of an elastomeric tube is based on the nonlinear theory of elasticity for incompressible materials employing the method of Ritz variations and the ANSYS finite-element solutions. The main purpose of the investigations is to obtain the loading diagrams in the total range of elastomeric tube thicknesses, without any kinematical and physical restrictions on the behavior of elastomer, e.g., neglecting the Kirchhoff and Timoshenko hypotheses or Hooke's la

Active twist of model rotor blades with D‐spar design

The design methodology based on the planning of experiments and response surface technique has been developed for an optimum placement of Macro Fiber Composite (MFC) actuators in the helicopter rotor blades. The baseline helicopter rotor blade consists of D‐spar made of UD GFRP, skin made of +450/‐450 GFRP, foam core, MFC actuators placement on the skin and balance weight. 3D finite element model of the rotor blade has been built by ANSYS, where the rotor blade skin and spar “moustaches” are modeled by the linear layered structural shell elements SHELL99, and the spar and foam ‐ by 3D 20‐node structural solid elements SOLID 186. The thermal analyses of 3D finite element model have been developed to investigate an active twist of the helicopter rotor blade. Strain analogy between piezoelectric strains and thermally induced strains is used to model piezoelectric effects. The optimisation results have been obtained for design solutions, connected with the application of active materials, and checked by the finite element calculations. First Published Online: 27 Oct 201

Solution of Electromagnetic Problem for an Application in Advanced Pultrusion Processes

To demonstrate features and benefits of electromagnetic energy source, the heating of rod profile made of polyester resin POLRES 305BV and glass fibres 4800 tex in cylindrical cavity resonator was studied. Materials with different dielectric properties: zirconium dioxide, boron nitride and quartz glass for a microwave transparent die were selected and analysed. The optimal diameter of ceramic die providing an effective and uniform electric field in the composite profile was found for each material

Application of macro-fiber composite (MFC) as a piezoelectric actuator

The aim of the present work is to investigate the use of Macro Fiber Composite (MFC) actuator for modal analysis of composite plate. Efficiency of application of MFC as an actuator in comparison with the impact hammer, PZT actuator and modal shaker has been investigated. POLYTEC laser Vibrometer operating on the Doppler principle and measuring back-scattered light from a vibrating panel has been used to determine its vibration velocity and displacement. Modal analysis is subsequently applied to extract natural frequencies and mode shape

Elastic instabilities in polymer tube of resonant sound absorbers under hydrostatic pressure

The solution of the problem of hydrostatic compression of an elastomeric tube is based on the nonlinear theory of elasticity for incompressible materials employing the method of Ritz variations and the ANSYS finite-element solutions. The main purpose of the investigations is to obtain the loading diagrams in the total range of elastomeric tube thicknesses, without any kinematical and physical restrictions on the behavior of elastomer, e.g., neglecting the Kirchhoff and Timoshenko hypotheses or Hooke's la