Design of Stress Constrained SiC/SiC Ceramic Matrix Composite Turbine Blades

Boyle, Robert; Gnanaselvam, Pritheesh; Parikh, Ankur H.; Ameri, Ali; Bons, Jeffrey P.; Nagpal, Vinod K.

doi:10.1115/1.4049776

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…Unidirectional SiC/SiC composites are commonly used in a cross-ply laminate configuration so that fibers can enhance the toughness in both in-plane directions. The FEA of the CMC vane, shown in Figure 26, is adapted from a previous work [43]. It includes an airfoil with a true chord length of 64.8 mm, a z-direction width of 41.9 mm, a suction side wall thickness of 2.03 mm, and a pressure side wall thickness of 1.02 mm.…”

Section: Nonlinear Behavior Of a Ceramic Matrix Composite Turbine Vanementioning

confidence: 99%

Micromechanics-Based Modeling of SiC/SiC Ceramic Matrix Composites and Structures

Mital¹,

Arnold²,

Bednarcyk³

et al. 2023

Recent Prog Mater

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The behavior and response of ceramic matrix composites (CMCs), in particular silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC), is affected by many factors such as variation of fiber volume fraction, residual stresses resulting from processing of the composites at high temperature, random microstructures, and the presence of matrix flaws (e.g., voids, pores, cracks etc.) as well as general material nonlinearity and heterogeneity that occurs randomly in a composite. Residual stresses arising from the phase change of constituents are evaluated in this paper and it is shown that they do influence composite strength and need to be properly accounted for. Additionally, the microstructures (location of fiber centers, coating thickness etc.) of advanced CMCs are usually disordered (or random) and fiber diameter and strength typically have a distribution. They rarely resemble the ordered fiber packing (square, rectangular, or hexagonal) that is generally assumed in micromechanics-based models with periodic boundary conditions for computational expediency. These issues raise the question of how should one model such systems effectively? Can an ordered hexagonal packed repeating unit cell (RUC) accurately represent the random microstructure behavior? How many fibers need to be included to enable accurate representation? Clearly, the number of fibers within an RUC must be limited to insure a balance between accuracy and efficiency. NASA’s in-house micromechanics-based code MAC/GMC provides a framework to analyze such RUCs for the overall composite behavior and the FEAMAC computer code provides linkage of MAC/GMC to the commercial FEA code, ABAQUS. The appropriate level of discretization of the RUC as well as the analysis method employed, i.e., Generalized Method of Cells (GMC) or High Fidelity Generalized Method of Cells (HFGMC), is investigated in this paper in the context of a unidirectional as well as a cross-ply laminated CMC. Results including effective composite properties, proportional limit stress (an important design parameter) and fatigue are shown utilizing both GMC as well as HFGMC. Finally, a few multiscale analyses are performed on smooth bar test coupons as well as test coupons with features such as open-hole and double notches using FEAMAC. Best practices and guidance are provided to take these phenomena into account and keep a proper balance between fidelity (accuracy) and efficiency. Following these guidelines can account for important physics of the problem and provide significant advantages when performing large multiscale composite structural analyses. Finally, to demonstrate the multiscale analysis framework, a CMC gas turbine engine vane structure is analyzed involving a progressive damage model.

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Section: Nonlinear Behavior Of a Ceramic Matrix Composite Turbine Vanementioning

confidence: 99%

Micromechanics-Based Modeling of SiC/SiC Ceramic Matrix Composites and Structures

Mital¹,

Arnold²,

Bednarcyk³

et al. 2023

Recent Prog Mater

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“…SiC ceramics are hard and brittle materials with high mechanical strength, excellent chemical stability, a small thermal expansion coefficient, and high resistance to wear and corrosion. They have been widely applied in aero-engine components and satellite optical mirrors [ 1 , 2 ]. In general, diamond grinding wheels, composed of monocrystalline diamond grit (M-diamond), serve as the main method for the manufacturing of SiC ceramics.…”

Section: Introductionmentioning

confidence: 99%

Material Removal Mechanism of SiC Ceramic by Porous Diamond Grinding Wheel Using Discrete Element Simulation

Zhang,

Xu,

Zhu

et al. 2024

Materials

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SiC ceramics are typically hard and brittle materials. Serious surface/subsurface damage occurs during the grinding process due to the poor self-sharpening ability of monocrystalline diamond grits. Nevertheless, recent findings have demonstrated that porous diamond grits can achieve high-efficiency and low-damage machining. However, research on the removal mechanism of porous diamond grit while grinding SiC ceramic materials is still in the bottleneck stage. A discrete element simulation model of the porous diamond grit while grinding SiC ceramics was established to optimize the grinding parameters (e.g., grinding wheel speed, undeformed chip thickness) and pore parameters (e.g., cutting edge density) of the porous diamond grit. The influence of these above parameters on the removal and damage of SiC ceramics was explored from a microscopic perspective, comparing with monocrystalline diamond grit. The results show that porous diamond grits cause less damage to SiC ceramics and have better grinding performance than monocrystalline diamond grits. In addition, the optimal cutting edge density and undeformed chip thickness should be controlled at 1–3 and 1–2 um, respectively, and the grinding wheel speed should be greater than 80 m/s. The research results lay a scientific foundation for the efficient and low-damage grinding of hard and brittle materials represented by SiC ceramics, exhibiting theoretical significance and practical value.

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“…Compared to superalloys, SiC/SiC CMC material merely weighs about one-third that could significantly reduce the centrifugal loads acting on the blades. 29 Gas turbines featuring superalloy blades in the expansion stages of the turbine, with the need for enhancement of TIT to achieve higher efficiencies, their hot gas path components would need to be replaced by materials such as CMCs. This may be achieved by replacing superalloy blades with CMC blades in existing turbines.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to superalloys, SiC/SiC CMC material merely weighs about one-third that could significantly reduce the centrifugal loads acting on the blades. 29…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of CMC bladed marine gas turbine-LM 2500: Effect of cycle operating parameters

Rathore

Kar

Sanjay

2022

International Journal of Engine Research

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Recent developments in ceramic-matrix composites and their successful use in combustor liners and shrouds have generated interest among researchers to adopt these materials in rotating gas turbine blades, especially in the first stages of high-pressure turbines where gas temperatures are highest. CMC blades have the potential of being retrofitted to replace superalloy turbine blades in operating gas turbines. In this paper, a comparative study on the thermodynamic performance of a marine gas turbine engine, LM 2500, featuring directionally solidified nickel superalloy blades versus novel CMC blades in the high-pressure turbine sections has been reported. Mathematical modeling of the gas turbine cycle components has been developed and then coded in C++ language. The effects of turbine inlet temperature on thermodynamic efficiencies, coolant mass flow rates, and work ratios on the two systems have been analyzed. Finally, the exergy analysis of the systems’ components has been done to identify the benefits of adopting CMC blades in the LM 2500 system. It has been observed that when compared to the directionally solidified bladed turbine system, the projected first law efficiency of CMC bladed LM 2500 gas turbines can be enhanced over 7% (from 34.17% to 41.21%). The projected work ratio can be improved by over 16% (from 0.49 to 0.57) at the turbine inlet temperature of 1725 K.

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Design of Stress Constrained SiC/SiC Ceramic Matrix Composite Turbine Blades

Cited by 7 publications

References 5 publications

Micromechanics-Based Modeling of SiC/SiC Ceramic Matrix Composites and Structures

Micromechanics-Based Modeling of SiC/SiC Ceramic Matrix Composites and Structures

Material Removal Mechanism of SiC Ceramic by Porous Diamond Grinding Wheel Using Discrete Element Simulation

Thermodynamics of CMC bladed marine gas turbine-LM 2500: Effect of cycle operating parameters

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