Jia Huang

Central South University | CSU · School of Aeronautics and Astronautics

The stress ratio (R) effect, especially at elevated temperatures, is associated with the fatigue crack growth (FCG) prediction in aero‐engine hot‐end components under complex operation conditions. The FCG experiments with three R were conducted on Ni‐based superalloy GH4169 at room temperature (RT), 550°C, and 700°C. The results indicate that the R...

Smooth and three types of U-shape single-edge notched plate specimens adopted to experimentally investigate stress rupture behavior of Ni-based Directionally Solidified (DS) superalloy at 850℃ exhibit notch weakening effect and multi-source cracking initiation near the notch root. However, stress rupture behavior of smooth and V-shape notched round...

Single crystal (SC) Ni-based superalloys undergo microstructural degradation such as rafting and coarsening due to the extremely harsh service environment, which consequently introduces the challenge in inelastic behaviours prediction when considering the time-varying microstructural state. Within this content, a thermodynamically microstructural s...

Combined tensile and bending fatigue (CTBF) behavior and failure mechanism of a blade-like specimen, made of the Ni-based alloy DZ125, are experimentally investigated. In order to reveal the geometrical feature and the stress state of the fillet between turbine blade bottom and platform, a blade-like specimen was designed. A novel high temperature...

Based on the COMSOL software, body forces substituted into the Reynolds-averaged Navier–Stokes (RANS) equations as the source terms instead of the actual blade rows were improved to better predict the compressor performance. Improvements in parallel body force modeling were implemented, central to which were the local flow quantities. This ensured...

This paper proposes a novel creep‐fatigue life estimation method considering the effect of non‐uniform stress state, through the comprehensively experimental and numerical investigation. Conventional and digital image correlation (DIC) based in‐situ creep‐fatigue tests were performed on thin‐walled plates with various types of holes at 850°C. DIC m...

In this study, a multilayer thermal protection system (TPS) of hollow cylindrical structure for hypersonic flight vehicles (HFVs) is modeled and its thermo-mechanical responses are investigated. The multilayer structure has an ultrahigh-temperature ceramic (UHTC) or a functionally graded ultrahigh-temperature ceramic (FG-UHTC) outer layer for heat...

Metal-organic frameworks (MOFs) have drawn a lot of interest as prospective starting points for highly effective electromagnetic wave (EMW) absorbers. However, the inevitable shrinkage and probable densification that occur during pyrolysis significantly reduce the microwave-loss capacity. A dual-layer MOF, ZIF-8@ZIF-67, is created and effectively d...

Varying thickness configurations have been applied to aero-engine turbine components. As a result, the thickness effect on the crack behavior must be considered in the damage tolerance method. The thickness effect remains a topic of discussion and needs further investigation due to limited studies on nickel-based superalloys. This study develops a...

A coupled phase field-viscoplasticity approach was developed to model the deformation and crack growth in a nickel-based superalloy under fatigue. The coupled model has an advantage in predicting the cyclic softening behavior of the alloy caused by fatigue damage, overcoming a major limitation of the original cyclic viscoplasticity model. The coupl...

Ceramic-fiber-reinforced SiO 2 aerogel (CFRSA) composite was used as core layer to prepare a stitched sandwich thermal protection structure (SSTPS). Mechanical properties of the SSTPS were experimentally investigated and compared with that of CFRSA, including flatwise tension, flatwise compression, edgewise compression and shear. Research results s...

Microstructure degradation of Ni-based superalloys operating at high temperatures for long terms inevitably occurs, which has a deteriorating effect on the mechanical properties of the alloy. In this study, the Chaboche elastic-viscoplastic constitutive model of a directionally solidified (DS) superalloy was modified by considering microstructure d...

Comprehensive characterization mechanical properties of aerogels and their composites are important for engineering design. In particular, some aerogel composites were reported to have varied tension and compression moduli. But conducting tension tests is difficult for the reason that low strength and brittleness will lead to unexpected failure in...

Comprehensive characterization mechanical properties of aerogels and their composites are important for engineering design. In particular, some aerogel composites were reported to have varied tension and compression moduli. But conducting tension tests is difficult for the reason that low strength and brittleness will lead to unexpected failure in...

Mechanical behaviour of Haynes 230 and Inconel 625 manufactured by selective laser melting (SLM) has been experimentally investigated in 870oC. Significant embrittlement of SLM Inconel 625 was found, accompanied by hardening behaviour during the test. Moreover, due to inhomogeneous grain deformation, the hardness dispersion of the two SLM alloys in...

Uniaxial tensile tests and stress-controlled low-cycle fatigue (LCF) and creep–fatigue interaction (CFI) tests of Inconel 625 alloy manufactured by selective laser melting (SLM) were performed at 815 °C in air environments. The microstructure was characterized by optical microscopy and scanning electron microscopy after testing. The results confirm...

Competing fatigue failure between the surface and internal nucleation has been widely observed in metals under the high cycle fatigue regime. To characterize different boundary conditions in surface and internal grain aggregates, a hybrid statistical volume element model was developed by binding two identical periodic stochastic polycrystal microst...

Arc ion plating was employed on a directionally solidified nickel-based superalloy to deposit a NiCrAlYSi coating. The failure behavior of the coated cylindrically specimens under thermomechanical fatigue loadings was experimentally investigated. The results show that the effect of coatings on TMF lives is dependent on the temperature ranges, and t...

The focus of this paper is to identify the material parameters of a crystal plasticity model for Ni-base single crystal superalloys. To facilitate the stepwise calibration of the multistage flow rules, further decoupling and simplification are implemented without compromising its simulating capability. Reduced-order kinematics in crystal plasticity...

Experimental investigations on the fatigue behavior of a near-alpha titanium alloy under typical cyclic loadings were carried out to simulate the service loading states applied on the engine blades. The axial stress-controlled tension–tension low-cycle fatigue (LCF) tests were carried out over a range of maximum stresses and stress ratios. The rota...

This paper is focused on developing suitable methodology for predicting creep characteristics (i.e., the minimum creep strain rate, stress rupture life and time to a specified creep strain) of typical Ni-based directionally solidified (DS) and single-crystal (SC) superalloys. A modern method with high accuracy on simulating wide ranging creep prope...

A simple unified critical plane damage parameter (i.e., the modified resolved shear strain range ∆γ mod) based on a slip mechanism-related critical plane concept was proposed in this paper, integrating life prediction of low cycle fatigue (LCF) behavior affected by anisotropy, load ratio and stress concentration into one framework, where the critic...

The feasibility of an accelerated test method on revealing the high cycle fatigue (HCF) limit stresses of a near alpha titanium alloy was successfully verified firstly during the rotary bending tests. The stress- controlled low cycle fatigue (LCF) tests at room temperature were then carried out over a range of maximum stresses and stress ratios to...

According to more recent work, the Wilshire equations have shown good prediction accuracy in a wide range of materials and stress-temperature conditions, particularly in extrapolation of short term results to long term predictions. In the current paper, this methodology was further developed for modeling anisotropic creep characteristics (i.e. mini...

Experimental investigation and numerical modeling on elasto-plastic notch-root stress/strain distributions under monotonic loadings of both the Ni-based directionally solidified (DS) superalloy and Titanium alloy were carried out simultaneously. For measuring inhomogeneous deformation fields at notch roots, an optical-numerical full-field surface d...

The complex deformation behaviors under tension-compression, cyclic, creep and creep-fatigue loadings of a nickel-base polycrystalline wrought superalloy at 650°C and 700°C were experimentally investigated. To uniformly simulate the complex deformation behaviors, the modified viscoplastic constitutive model combined with both the Kachanov damage ev...

The effect of notch types and stress concentration factors (Kt) on low cycle fatigue life and cracking of the DZ125 directionally solidified superalloy has been experimentally investigated. Single-edge notched specimens with V and U type geometries were tested at 850 °C with stress ratio R = 0.1. High temperature in situ optical method was used to...

A simple method to analyse the notch sensitivity of specimens in fatigue tests is presented. The parameter m, which can be used to measure the notch sensitivity, the nominal stress and the stress concentration factor (Kt) are used to establish the method. In order to verify the feasibility of the method, notch fatigue test results from our group an...

Notched fatigue behavior of directional solidified superalloy DZ125 at 850 °C was investigated. Different U type notched specimens with three stress concentration factors including 1.91, 3.01, and 4.35 were tested. Crack initiation and propagation were observed in situ. The fatigue life and crack initiation and propagation were analyzed. The result...

Based on the importance of overall parameters for the subsequent detailed design, the potential problems of the strength in the concept design phase was investigated, then the effects of design parameters, such as AN2, wheel speed, solidity of blade and performance of the materials, on strength and life were studied. The results show that the value...

Considering the effects of temperature, rotating speed and pressure difference in engine operating conditions for predicting changes in turbine tip clearance, a modified reduced model was presented. In the process of designing structures for high pressure turbine in an aircraft engine, tip clearance was predicted using this modified model, and resu...