Abstract This study investigates the defect evolution mechanisms in nickel-based GH4169 superalloy fabricated using selective laser melting (SLM) under high-temperature fatigue. X-ray computed tomography (CT) was employed for three-dimensional characterization, and in-situ fatigue tests were conducted at 400°C. Initial defects found to be randomly distributed, primarily consisting of pores lack-of-fusion (LOF) defects, with 80% having an equivalent diameter smaller than 20 μm. Pores...

The oxygen pump constitutes a crucial and intricate component within liquid rocket engines, serving as primary source of engine vibration. This study delves into the unsteady fluid-induced excitation loading, considering interplay between gap flow main flow. findings are validated through testing on engine. Modal characteristics under varying mediums examined. Rayleigh damping parameter is determined, accounting for frequency excitation, thereby establishing comprehensive transient dynamic...

Abstract Traditional unidirectional cold expansion technology usually generates non-uniform distribution of residual stress in the thickness direction holes, which is harmful to improvement fatigue life holes. The present work proposed a bi-directional procedure realize homogenization expanded hole, thereby further improved antifatigue performance hole. For this aim, series finite element (FE) simulations were carried out investigate effectiveness and optimize process parameters. results...

Purpose Reinforced S-shape bellows are novel metal with high pressure resistance. Displacement compensation ability is a key index in the design of bellows. Axial-tension-compression deformation and bending two typical displacement forms. Thus, analysis axial stiffness important structure design. Design/methodology/approach In this study, theory analytics tension compression reinforced S-shaped derived, load-displacement relationship during obtained by correcting geometric parameters...

Purpose Regeneratively cooled thrust chamber is a key component of reusable liquid rocket engines. Subjected to cyclic thermal-mechanical loadings, its failure can seriously affect the service life QCr0.8 copper alloy widely used in walls due excellent thermal conductivity, and mechanical fatigue properties are essential for evaluation life. This paper contributes understanding damage mechanism material selection regeneratively chambers Design/methodology/approach In this paper, tensile...

Static aeroelastic and flutter characteristics of an aircraft composite wing with high aspect ratio were analysed by effective Computational Fluid Dynamics Structure coupled method. Effects stiffness distribution on considered. Honeycomb core sandwich was considered to be equivalent orthotropic material inertance method allow highly efficient numerical simulation, which used for analysis bending torsional distribution. The results showed that the redistributed aerodynamic load leads a...

Purpose Computational efficiency is always the major concern in aircraft design. The purpose of this paper to investigate an efficient aeroelasticity optimization design method. Analysis composite wing elastic axis presented current study and its application on discussed. Design/methodology/approach Elastic consists stiffness centers. centers eight cross sections are analyzed obtained through least‐squares procedure. In analysis section center, model approximated by assuming as a thin walled...

The complex aeroelastic equation of an aircraft wing with freeplay nonlinearity was built and applied for response analysis. This took into account multiple lumped mass points directions the control surface using Roger rational function approximation. aerodynamic analysis based on subsonic doublet lattice method external program time history employed. results show that amplitudes generalized displacement considering effect is decreased compared those not effect, influenced by stiffness...

Turbo pump is one of the elements with most complex flow liquid rocket engine, and as an important component turbo pump, impeller weak point affecting its reliability. In this study, a noncontact modal characteristic identification technique was proposed for oxygen impeller. Modal characteristics under three different submerged media, air, pure water, brine same density oxygen, were tested based on technology. Submersion state directly affects frequencies damping ratio. The transient...

A mesh regeneration method was put forward, and its application on the jig-shape optimization design of a high-aspect-ratio wing carried out in present study. In method, some control lines were selected based configuration characters structure firstly. And then new aerodynamic model built according to distribution which always keeps same outline. Finally, generation quality out. Three different optimizations wing. All them can obtain designed jig-shapes have excellent agreement with...

Purpose The fracture mechanism of S-07 steel was investigated by observing the surface specimens with scanning electron microscope (SEM). Furthermore, overall elastic–plastic behaviors and stress state evolution during loading procedure all were simulated FE analysis to obtain local strain at crack nucleated location average triaxiality each type specimen. Design/methodology/approach Three types tests under various states performed study ductile characteristics high strength in quasi-static...

The load-carrying capacities of welded joints need to be paid attention in the design frame, which transfers thrust generated by rocket engine body. A capacity evaluation method based on structural stress is proposed this study. Both ultimate and fracture section angle are precisely obtained method. At same time, a definition weld-failure given tests. frame analyzed through finite element model, including overall structure local weld details. analysis three types structures—standard shear...

The purpose of this study was to investigate the wetting behavior and interfacial reactions Sn-Ti alloys, which has been widely applied join ceramics with metals, on Si3N4 substrates. isothermal process Sn-xTi alloys (x = 0.5, 1.0, 1.5, 2.0 2.5 wt.%) systematically studied from 1223 K 1273 through sessile drop methods. microstructures interface were characterized by X-ray diffraction (XRD) microscope (SEM). active Ti element remarkably enhanced wettability melts substrates because formation...