Dry friction dampers are widely used to reduce vibration. The forced vibration response of a simplified turbine blade with new kind under-platform dry is studied in this paper. model consists clamped as two rigidly connected beams and the form masses which allowed slide along platform horizontal direction vibrate vertical direction. vibrations dampers, transverse coupled by at contact interfaces assumed follow classical discontinuous Coulomb’s law friction. motion leads time-varying forces...

This study proposes a bluff body non-rotational galloping-based piezoelectric wind energy harvester (BNRGH) for overall output performance enhancement. The used in this structure is designed to be available rotate with respect the free end of two cantilever beams by connection rotatable hinges. A series comparisons are conducted experimentally tunnel between proposed and conventional harvester, which commonly configured single beam. results show that capable preventing variation attack angle...

This article studies energy dissipation of a friction damper (due to stick–slip vibration) in the context harmonic excitation. There are numerous applications such dampers engineering. One particular example is new kind under-platform dry for aero engines. The model consists clamped cross-like beam structure and two masses (friction dampers) contact with short cross. allowed slide along extra vertical beams. They can exhibit three distinct dynamic regimes: pure slip, stick mixture relative...

The bilinear hysteresis friction model and the Coulomb are two typical macro slip models which widely used by researchers in simulation analysis of rub-impact dynamics shrouded blades. However, differences results blades based on these have not well been studied recently. In this paper, a two-dimensional lumped mass including axial displacements tangential is established, kinetic equations under different contact conditions derived. contact-separation stick-slip transition points determined...

The effectiveness of shot peening is mainly determined by the coverage. coverage required to be 100% for current technical standards peening. With increase material strength, higher in process. However, influence high on Almen intensity and residual compressive stress unclear, difficulty lies lack quantitative description finite element analysis. To analyze stress, firstly an approximate based dent size, distance shots numbers proposed this study. Based coverage, arc height test are...

High-cycle fatigue (HCF) failure of the turbine blades aero-engines caused by high vibrational stresses is one main causes aero-engine incidents [...]

Shroud devices which are typical cyclic symmetric structures widely used to reduce the vibration of turbine blades in aero engines. Asymmetric rub-impact adjacent shrouds or aerodynamic excitation forces can excite bending-torsion coupling shrouded blades, will lead complex contact motions. The aim this paper is study dynamic characteristics using a numerical method. contact-separation transition mechanism under motions studied, corresponding boundary conditions set up, and influence moments...

Friction plays a crucial role in various engineering fields, including advanced manufacturing, transportation, aerospace, and bioengineering [...]

Chatter stability analysis is an effective way to optimize the cutting parameters and achieve chatter-free machining. This paper proposes a milling chatter method based on localized differential quadrature (LDQM), which has advantages of simple principle, easy application, high computational efficiency. The process, considering regeneration effect, modeled using linear periodic delay equations (DDE), then state transition matrix during adjacent period constructed LDQM, finally, process...

This paper aims to explore the material properties of RPC and transverse-bending performance, as well crack-width-calculation theory a densely reinforced steel–RPC composite structure with different fiber parameters. Two types (straight fiber, hybrid fiber) four volume contents (2%, 2.5%, 3%, 3.5%) were selected mechanical materials, influences parameters on compressive strength, modulus elasticity, flexural strength axial tensile property investigated. Eight plates design (fiber type...

Chatter causes great damage to the machining process, and selection of appropriate process parameters through chatter stability analysis is significance for achieving chatter-free machining. This article proposes a milling method based on barycentric rational interpolation differential quadrature (DQM). The dynamics considering regeneration effect first modelled as time-delay equation (DDE). When adjacent pitch angles cutter are symmetric, dynamic contains single time delay. Otherwise, when...

Abstract An integrated fabrication process based on multi‐material Digital Light Processing (DLP) technique for metamaterial absorbers (MMAs) is proposed. Considering the requirements of DLP rheological properties and photocuring slurry, a photopolymer resin slurry was developed using silver‐plated carbon fiber (CF@Ag) hollow glass microspheres (HGMs@Ag) as conductive fillers. To meet conductivity resistive films in MMAs, study systematically investigated influence material parameters...

Dry friction contact is widely used to reduce vibration in engineering, especially the reduction of turbine blades, which are major components aeroengines [...]

The mechanism of a floating ring in the bearing system is investigated. Based on Hirs' bulk flow theory, Moody's frication factor equation and generalized incompressible Reynolds Equation, considering elastic deformation whirling motion ring, model governing under turbulence state were set up. result numerical example showed that new can effectually reduced strong non-linearity oil film rigidity which originated by large unbalance; As positive pressure zone moved circumferential direction.

Two novel polyurethane films were successfully synthesized. One was from hydroxylated tung oil (HTO) and polymethylene polyphenyl isocyanate (PAPI), which designated as HTO-PAPI; the other HTO end-capped a traditional prepolymer PAPI, PP-HTO-PAPI. FTIR NMR results show that prepared HTO-PAPI PP-HTO-PAPI are expected structures. Mechanical testing result shows Young's modulus elongation at break for 282.13 MPa, 1.8 MPa 14.15%, 218.23%, respectively, indicating two have very distinctive...

The nonlinear forced vibration responses of integrally shrouded turbine blade considering different contact state are investigated in this paper. A lumped mass model separation and reattachment adjacent shrouds centrifugal stiffening effects is established its dynamic equation deduced. Collision force approximated by linear cubic springs together which more realistic, friction an exponential-type velocity-dependent model. Numerical results indicate that displays very complex phenomena it can...

Abstract In this study, we introduced 1:1 internal resonance in a magnetically coupled 2-degree-of-freedom (2-DOF) galloping-based piezoelectric energy harvester to improve the harvesting efficiency. The governing equations for proposed aero-electro-mechanical system considering effect of oscillating wake are established using extended Hamilton principle, and method multiple scale is exploited obtain approximate analytical solutions. Parameter sweeping numerical calculation conducted...