NUMERICAL MODELLING OF BIRD STRIKE ON A ROTATING ENGINE BLADES BASED ON VARIATIONS OF POROSITY DENSITY

A numerical investigation is conducted on a rotating engine blade subjected to a bird strike impact. The bird strike is numerically modelled as a cylindrical gelatine with hemispherical ends to simulate impact on a rotating engine blade. Numerical modelling of a rotating engine blade has shown that bird strikes can severely damage an engine blade, especially as the engine blade rotates, as the rotation causes initial stresses on the root of the engine blade. This paper presents a numerical modelling of the engine blades subjected to bird strike with porosity implemented on the engine blades to investigate further damage assessment due to this porosity effect. As porosity influences the decibel levels on a propeller blade or engine blade, the damage due to bird strikes can investigate the compromise this effect has on the structural integrity of the engine blades. This paper utilizes a bird strike simulation through an LS-Dyna Pre-post software. The numerical constitutive relations are keyed into the keyword manager where the bird’s SPH density, a 10 ms simulation time, and bird velocity of 100 m/s are all set. The blade rotates counter-clockwise at 200 rad/s with a tetrahedron mesh. The porous regions or voids along the blade are featured as 5 mm diameter voids, each spaced 5 mm apart. The bird is modelled as an Elastic-Plastic-Hydrodynamic material model to analyze the bird’s fluid behavior through a polynomial equation of state. To simulate the fluid structure interaction, the blade is modelled with Johnson-Cook Material model parameters of aluminium where the damage of the impact can be observed. The observations presented are compared to previous study of a bird strike impact on non-porous engine blades. ABSTRAK: Penyelidikan berangka telah dijalankan ke atas bilah enjin berputar tertakluk kepada impak pelanggaran burung. Pelanggaran burung tersebut telah dimodelkan secara berangka sebagai silinder gelatin dengan hujungnya berbentuk hemisfera demi mensimulasikan impaknya ke atas bilah enjin yang berputar. Pemodelan berangka bilah-bilah enjin yang berputar tersebut menunjukkan bahawa pelanggaran burung mampu menyebabkan kerosakan teruk terhadap bilah enjin terutamanya apabila bilah enjin sedang berputar oleh sebab putaran menghasilkan tekanan asal di pangkal bilah enjin. Kajian ini mengetengahkan pemodelan berangka ke atas bilah-bilah enjin tertakluk kepada pelanggaran burung terhadap bilah-bilah enjin yg mempunyai keliangan demi menyelidik dan menilai kerosakan kesan daripada keliangan tersebut. Keliangan juga mempengaruhi tahap-tahap desibel ke atas bilah kipas ataupun bilah enjin, kerosakan hasil serangan burung boleh menterjemah tahap ketahanan struktur integriti bagi bilah-bilah enjin tersebut. Penyelidikan ini mengguna pakai perisian “LS-Dyna Pre-post” untuk simulasi pelanggaran burung. Hubungan konstitutif berangka telah dimasukkan sebagai kata kunci di mana ketumpatan SPH burung, masa simulasi 10ms, dan halaju burung ditetapkan kepada 100 m/s. Bilah tersebut berputar pada 200 rad/s arah lawan jam dengan jejaring tetrahedron. Kawasan berliang atau kosong di sepanjang bilah ditetapkan diameternya kepada 5 mm, dan dijarakkan 5 mm di antara satu sama lain. Burung pula dimodelkan sebagai material “Elastic-Plastic-Hydrodynamic” untuk mengkaji sifat bendalir burung melalui persamaan polinomial. Demi mensimulasi interaksi struktur bendalir, bilah tersebut dimodelkan sebagai parameter aluminium material “Johnson Cook” di mana kerosakan daripada impak tersebut dapat diteliti. Penelitian-penelitian tersebut dibandingkan dengan kajian terdahulu ke atas serangan burung terhadap bilah-bilah enjin tidak berliang.

Increase in productivity and quality based on the control of thermodynamic processes during deep profile grinding of the gas-turbine engine blade

The article provides the system of interaction of dynamic processes during deep profile grinding of complex profiles on a multiaxis machine, the influence of dynamic processes on the quality of the surface layer, the endurance limit of the gas-turbine engine blade. The method presented allows to assign corresponding grinding modes based on the forecast of the dynamics of elastic, thermal and working processes in a thermomechanical system. This technique allows to control the process of deep profile grinding to achieve the specified parameters of surface quality, the endurance limit of the blade and increase process efficiency.

A Novel Automatic Algorithm for Estimating the Jet Engine Blade Number of Insufficient JEM Signals

One of the major issues in multifunction radars is time resource allocation to maximize the radar’s ability. If jet engine modulation (JEM) is more efficiently performed in an insufficient dwell-time environment, the remaining time can be allocated for other tasks. This study presents a novel automatic algorithm for estimating the jet engine blade number of insufficient JEM signals. We employed a harmonic selection rule and a modified empirical mode decomposition (EMD) with an adaptive low-pass filtering. For a refined autocorrelation waveform, the analysis focuses on a desirable combination of intrinsic mode functions derived from the modified EMD. The approach is significant because it enables reliable estimation despite the insufficient JEM signal. Also, the proposed algorithm is innovative because it uses only the time-domain method, not the frequency-domain method. The application is expected to enhance the efficiency of radar resource management.

Investigation of the Effect of Vibration Characteristics on the Grinding Performance of Aero-Engine Blade Tip

The machining quality of the blade tip has a great influence on the service performance and life of the aero-engine blade. The recent paper investigates the effect of vibration during the grinding process of the GH4169 nickel-based superalloy blade tip. Moreover, this paper proposes a theoretical model to link the unbalance of the grinding wheel, the vibration, and the surface topography characteristics of the blade. The results show that the blade vibration during grinding and the resulting non-linear change of the grinding depth could reduce the surface quality of the blade tip, and lead to differences in the surface quality of the blade tip in different areas, where the surface roughness in the entry area zone I is the largest, in the exit area zone III is the second largest, and the intermediate area zone III is the smallest. Grinding depth has a greater impact on the difference of the surface quality in the blade tip grinding process, especially when the grinding depth is greater than 4 μm, the difference of surface roughness increases significantly. On the other hand, the feed rate has little effect on the difference in surface quality. Adding damping block can reduce the surface roughness of the blade tip, however, it does not reduce the difference in surface quality.

The numerical optimization methods usage for choosing blisk trajectory during PVD coating deposition

PVD coating deposition is a considerable way to prevent the gas turbine engine blade from erosive wear. However, the process for blisks is complicated by the part complex shape which leads to uneven film thickness. The research considers an approach for optimizing the blisk trajectory in a vacuum chamber. This approach reduced the calculated non-uniformity of the coating thickness from 4.3-10.8 to 6.2-10.4 μm.

Research on Constant Force Polishing Control of Aero-engine Blade Based on Expanded State Observer

This paper presents a parallel control method based on the expanded state observer (ESO) for aero-engine blade robot polishing. Aiming to reduce the fluctuation of polishing force caused by environmental noise and modeling errors. First, calibrate six-dimensional force sensor according to the maximum acceleration of the end effector during the polishing process. Then, build the gravity compensation and zero drift compensation model. Besides, use this model to compensate measurement error of the six-dimensional force sensor. Finally, calculate the error between the expected polishing force and the actual feedback value and its derivative value. Use calculation results to design the control boundary layer. The polishing force controller is divided into two parallel control loops to design. When the switching value is in the control boundary layer. A nonlinear active disturbance rejection control (ADRC) loop is used. When the switching value is outside the control boundary layer. An ESO-based sliding mode control (SMC) loop is used. Simulation and experimental results show that the proposed parallel control method based on ESO has a fast response and high robustness compared with FuzzyPID, PID, and ADRC. It can effectively suppress the force fluctuation in the polishing process and significantly improve the surface processing quality of the aero-engine blade.