Contribution in Optimization of Honeycomb Abradable Seals Structure

2021 ◽  
Author(s):  
P. Pathak ◽  
D. Dzhurinskiy ◽  
A. Elkin ◽  
P. Shornikov ◽  
S. Dautov ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Energy Demand ◽  
Mechanical Performance ◽  
Minimum Weight ◽  
Innovative Technology ◽  
Element Analysis ◽  
Cross Sectional ◽  
Spray System ◽  
Seal Design ◽  
Temperature Capability

Abstract The abradable coatings had significantly enhanced turbomachinery performance by acting as a sacrificial seal between rotating blades and stationary casing. Further improvement in seal design to meet the higher energy demand and increase the service time has been the key challenges to solve in the gas turbine industry. Honeycomb seals have become the industry standard clearance seal technique due to their unique design and high structural strength with minimum weight. The present study proposes a concept to form a thermal shock resistance structure to achieve higher temperature capability and improve the reliability of abradable seal structures. A cavity layer of honeycomb seal structure made of SS 321 alloy was coated with advanced high-temperature ZrO2+7.5%Y2O3+4% polyester seal material using TriplexPro-210 plasma spray system. The integrity of a seal structure was assessed by a cross-sectional analysis and evaluation of the coating microstructure. Additionally; the microhardness test was performed to estimate coating fracture toughness; and Object-Oriented Finite Element analysis was used to assess its thermo-mechanical performance. The concept proposed in this study should be further validated to develop the most capable innovative technology for advanced gas turbine abradable seal structures.

Design and Analysis of a New Accessory Gearbox Housing for a Gas Turbine Engine

2011 ◽  
Author(s):  
Partha S. Das
Keyword(s):  
Gas Turbine ◽  
Low Cycle Fatigue ◽  
Minimum Weight ◽  
Cost Savings ◽  
Gas Turbine Engine ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Turbine Engine ◽  
Housing Design ◽  
Engine Mount

Accessory Gearbox (AGB) Housing is one of the most critical components of a gas turbine engine that lies between the core engine & the aircraft. The function of the AGB Housing is to provide support for the gear drive assembly that transfers power from the engine to the engine accessories and to the power takeoff drive for the aircraft accessories. The housing also functions as an oil tight container and passageway for lubrication. In addition, the AGB housing provides mount points to attach engine/aircraft support accessories, including the engine mount points to the aircraft. The complexity in predicting AGB housing behavior under the gear loading, engine loading and engine induced vibration is one of the main challenges of designing a new gearbox with minimum weight. To address these issues, the current paper presents for the first time the design-analysis of a new lightweight AGB housing for a turboshaft engine, based on the following three major requirements: i) gear bearing pads strength & stiffness capability, ii) AGB mount pads (for accessories and for engine) load carrying capability, and, iii) vibratory response (mainly high cycle fatigue (HCF) response) of the AGB housing. A 3-D Finite Element Analysis (FEA) model of the AGB housing was developed using the proposed initial design. Various design modifications, involving several interrelated, iterative steps, were then carried out by adjusting and modifying the housing wall thickness, placement & sizes of internal ribs and external gussets, including additional geometric modifications to satisfy the design objectives. The result is a robust, lightweight AGB housing design, eliminating the need for some of the required testing for the qualification of the new gearbox, indicating a significant cost savings. This paper also discusses in detail the methodology for the gear bearing pad strength/stiffness calculation, the FEA modeling techniques for the application of mount loads and gear bearing loads under operating & flight maneuver conditions, and, a methodology for addressing a combined HCF & LCF (Low Cycle Fatigue) response of the housing.

A Preliminary Design System for Turbine Discs

2014 ◽  
Author(s):  
Yannick Ouellet ◽  
François Garnier ◽  
François Roy ◽  
Hany Moustapha
Keyword(s):  
Computer Aided Design ◽  
Mechanical Performance ◽  
Minimum Weight ◽  
Design System ◽  
Analysis Tool ◽  
Preliminary Design ◽  
Design Phase ◽  
Element Analysis ◽  
Turbine Disc ◽  
Parameterized Model

In order to improve product development cycle, design engineers use multi-disciplinary analysis tools which allow better productivity. This paper covers the development of new tools to improve the preliminary design phase of turbine disc, being a critical part of aircraft engines. First, a new single platform D&A (Design & Analysis) tool integrating commercial CAD (Computer Aided Design) and FEA (Finite Element Analysis) software processing in batch mode is presented. This integrated architecture leads to a real improvement enabling a cohesive single integrated simulation environment that offers significant time reduction on user manipulation and execution. An optimization of disc geometry is then performed by using different optimization algorithms and configurations for a given disc parameterized model. The results show potential improvement over the current preliminary rotor discs for life and burst limited design. Finally, optimal curves obtained by developing HPT (High Pressure Turbine) disc reference charts, indicate how to get the minimum weight for given mechanical performance without running any structural analysis. These new tools supporting disc design have allowed improvement of disc life and durability leading to reduction of preliminary design phase duration.

Mechanical Performance of Tubular Microtruss Materials Reinforced With Nanocrystalline Sleeves

2011 ◽  
Vol 1304 ◽  
Author(s):  
Eral Bele ◽  
Mishaal Azhar ◽  
Glenn D. Hibbard
Keyword(s):  
Mechanical Performance ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Structural Performance ◽  
Element Analysis ◽  
Cross Sectional ◽  
Polymeric Scaffolds ◽  
Characteristic Features ◽  
Inherent Strength ◽  
Material Grain Size

ABSTRACTMicrotruss cellular materials are assemblies of struts with characteristic features in the μm to mm scale, arranged in a periodic, three-dimensional architecture. Compared to conventional cellular architectures (e.g. stochastic foams and honeycombs), they can possess improved structural efficiency, because externally applied loads are resolved axially along the constituent struts. We have recently fabricated composite microtruss materials by electrodepositing reinforcing nanocrystalline sleeves on tubular polymeric scaffolds. These materials can offer enhanced structural performance by exploiting advantageous properties along three length scales: the inherent strength of the electrodeposited material (grain size reduction to the nm scale), its location away from the bending axis of the struts (cross-sectional efficiency in the μm scale), and the spatial arrangement of the struts (architectural efficiency in the mm scale). This study uses finite element analysis and experimental methods to characterize the mechanical properties of these composite materials.

A Preliminary Design System for Turbine Discs

2017 ◽  
Vol 0 (0) ◽  
Author(s):  
Yannick Ouellet ◽  
Christian Savaria ◽  
François Roy ◽  
Hany Moustapha ◽  
François Garnier
Keyword(s):  
Computer Aided Design ◽  
Mechanical Performance ◽  
Minimum Weight ◽  
Design System ◽  
Analysis Tool ◽  
Preliminary Design ◽  
Design Phase ◽  
Element Analysis ◽  
Turbine Disc ◽  
Parameterized Model

AbstractIn order to improve product development cycle, design engineers use multidisciplinary analysis tools which allow for better productivity. This paper covers the development of new tools to improve the preliminary design phase of turbine disc, being a critical part of aircraft engines. First, a new single platform D&A (Design & Analysis) tool integrating commercial CAD (Computer Aided Design) and FEA (Finite Element Analysis) software processing in batch mode is presented. This integrated architecture leads to a real improvement, enabling a cohesive single integrated simulation environment that offers significant time reduction on user manipulation and execution. An optimization of disc geometry is then performed by using different optimization algorithms and configurations for a given disc parameterized model. The results show potential improvement over the current preliminary rotor discs for life and burst limited design. Finally, optimal curves obtained by developing HPT (High Pressure Turbine) disc reference charts, indicate how to get the minimum weight for given mechanical performance without running any structural analysis. These new tools supporting disc design have allowed improvement of disc life and durability leading to a reduction of preliminary design phase duration.

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020 ◽  
pp. 136943322098170
Author(s):  
Michele Fabio Granata ◽  
Antonino Recupero
Keyword(s):  
Analytical Model ◽  
Prestressed Concrete ◽  
3D Analysis ◽  
Box Girders ◽  
Element Analysis ◽  
Cross Sectional ◽  
Interaction Domains ◽  
Global And Local ◽  
Resultant Forces

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

scholarly journals Design and Characterization of Microscale Auxetic and Anisotropic Structures Fabricated by Multiphoton Lithography

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 446
Author(s):  
Ioannis Spanos ◽  
Zacharias Vangelatos ◽  
Costas Grigoropoulos ◽  
Maria Farsari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Mechanical Responses ◽  
Multiphoton Lithography ◽  
Anisotropic Structures ◽  
Scanning Electron

The need for control of the elastic properties of architected materials has been accentuated due to the advances in modelling and characterization. Among the plethora of unconventional mechanical responses, controlled anisotropy and auxeticity have been promulgated as a new avenue in bioengineering applications. This paper aims to delineate the mechanical performance of characteristic auxetic and anisotropic designs fabricated by multiphoton lithography. Through finite element analysis the distinct responses of representative topologies are conveyed. In addition, nanoindentation experiments observed in-situ through scanning electron microscopy enable the validation of the modeling and the observation of the anisotropic or auxetic phenomena. Our results herald how these categories of architected materials can be investigated at the microscale.

scholarly journals Computational and experimental mechanical performance of a new everolimus-eluting stent purpose-built for left main interventions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabhi Samant ◽  
Wei Wu ◽  
Shijia Zhao ◽  
Behram Khan ◽  
Mohammadali Sharzehee ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Patient Specific ◽  
Wall Structure ◽  
Left Main ◽  
Element Analysis ◽  
Stent Expansion ◽  
Radial Strength ◽  
Different Diameters

AbstractLeft main (LM) coronary artery bifurcation stenting is a challenging topic due to the distinct anatomy and wall structure of LM. In this work, we investigated computationally and experimentally the mechanical performance of a novel everolimus-eluting stent (SYNERGY MEGATRON) purpose-built for interventions to large proximal coronary segments, including LM. MEGATRON stent has been purposefully designed to sustain its structural integrity at higher expansion diameters and to provide optimal lumen coverage. Four patient-specific LM geometries were 3D reconstructed and stented computationally with finite element analysis in a well-validated computational stent simulation platform under different homogeneous and heterogeneous plaque conditions. Four different everolimus-eluting stent designs (9-peak prototype MEGATRON, 10-peak prototype MEGATRON, 12-peak MEGATRON, and SYNERGY) were deployed computationally in all bifurcation geometries at three different diameters (i.e., 3.5, 4.5, and 5.0 mm). The stent designs were also expanded experimentally from 3.5 to 5.0 mm (blind analysis). Stent morphometric and biomechanical indices were calculated in the computational and experimental studies. In the computational studies the 12-peak MEGATRON exhibited significantly greater expansion, better scaffolding, smaller vessel prolapse, and greater radial strength (expressed as normalized hoop force) than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY (p < 0.05). Larger stent expansion diameters had significantly better radial strength and worse scaffolding than smaller stent diameters (p < 0.001). Computational stenting showed comparable scaffolding and radial strength with experimental stenting. 12-peak MEGATRON exhibited better mechanical performance than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY. Patient-specific computational LM stenting simulations can accurately reproduce experimental stent testing, providing an attractive framework for cost- and time-effective stent research and development.

scholarly journals Estimating Deterioration in the Concrete Tie-Ballast Interface Based on Vertical Tie Deflection Profile: A Numerical Study

2016 ◽  
Author(s):  
Hailing Yu
Keyword(s):  
Direct Detection ◽  
Numerical Study ◽  
Interface Condition ◽  
Vertical Deflection ◽  
Cohesive Elements ◽  
Material Loss ◽  
Element Analysis ◽  
Cross Sectional ◽  
Technical Requirements ◽  
Support Conditions

In ballasted concrete tie track, the tie-ballast interface can deteriorate resulting in concrete tie bottom abrasion, ballast pulverization and/or voids in tie-ballast interfaces. Tie-ballast voids toward tie ends can lead to unfavorable center binding support conditions that can result in premature concrete tie failure and possible train derailment. Direct detection of these conditions is difficult. There is a strong interest in assessing the concrete tie-ballast interface conditions indirectly using measured vertical deflections. This paper seeks to establish a link between the vertical deflection profile of a concrete tie top surface and the tie-ballast interface condition using the finite element analysis (FEA) method. The concrete tie is modeled as a concrete matrix embedded with prestressing steel strands or wires. The configurations of two commonly used concrete ties, one with 8 prestressing strands and the other with 20 prestressing wires, are employed in this study. All models are three-dimensional and symmetric about the tie center. A damaged plasticity model that can predict onset and propagation of tensile cracks is applied to the concrete material. The steel-concrete interface is homogenized and represented with a thin layer of cohesive elements sandwiched between steel and concrete elements. Strand- or wire-specific elasto-plastic bond models developed at the Volpe Center are applied to the cohesive elements to account for the interface bonding mechanisms. FE models are developed for both original and worn concrete ties, with the latter assuming hypothetical patterns of reduced cross sections resulting from abrasive interactions with the ballast. Static analyses of pretension release in these concrete ties are conducted, and vertical deflection gradients along tie lengths are calculated and shown to correspond well with the worn cross sectional patterns for a given reinforcement type. The ballast is further modeled with Extended Drucker-Prager plasticity, and hypothetical voids are applied toward the tie ends along the concrete tie-ballast interface to simulate center binding support conditions. The distance range over which the concrete tie is supported in the center is variable and yields different center binding severity. Static simulations are completed with vertical rail seat loads applied on the concrete tie-ballast assembly. The influences of various factors on the vertical deflection profile, including tie type, vertical load magnitude, center binding severity, cross sectional material loss and prestress loss, are examined based on the FEA results. The work presented in this paper demonstrates the potential of using the vertical deflection profile of concrete tie top surfaces to assess deteriorations in the tie-ballast interface. The simulation results further help to clarify minimum technical requirements on inspection technologies that measure concrete tie vertical deflection profiles.

Field Conversion of a Low-Firing Frame 7B Gas Turbine Power Plant to Ultra-Low Emission Combustion

2015 ◽  
Author(s):  
Nicolas Demougeot ◽  
Jeffrey A. Benoit
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Energy Demand ◽  
Water Injection ◽  
Cost Benefit ◽  
High Energy ◽  
Nox Emissions ◽  
Environmental Controls ◽  
Low Emission ◽  
Technical Discussion

The search for power plant sustainability options continues as regulating agencies exert more stringent industrial gas turbine emission requirements on operators. Purchasing power for resale, de-commissioning current capabilities altogether and repowering by replacing or converting existing equipment to comply with emissions standards are economic-driven options contemplated by many mature gas turbine operators. NRG’s Gilbert power plant based in Milford, NJ began commercial operation in 1974 and is fitted with four (4) natural gas fired GE’s 7B gas turbine generators with two each exhausting to HRSG’s feeding one (1) steam turbine generator. The gas turbine units, originally configured with diffusion flame combustion systems with water injection, were each emitting 35 ppm NOx with the New Jersey High Energy Demand Day (HEED) regulatory mandate to reduce NOx emissions to sub 10 ppm by May 1st, 2015. Studies were conducted by the operator to evaluate the economic viability & installation of environmental controls to reduce NOx emissions. It was determined that installation of post-combustion environmental controls at the facility was both cost prohibitive and technically challenging, and would require a fundamental reconfiguration of the facility. Based on this economic analysis, the ultra-low emission combustion system conversion package was selected as the best cost-benefit solution. This technical paper will focus on the ultra low emissions technology and key features employed to achieve these low emissions, a description of the design challenges and solution to those, a summary of the customer considerations in down selecting options and an overview of the conversion scope. Finally, a technical discussion of the low emissions operational flexibility will be provided including performance results of the converted units.

Eccentric ergometry: increases in locomotor muscle size and strength at low training intensities

2000 ◽  
Vol 278 (5) ◽  
pp. R1282-R1288 ◽  
Author(s):  
P. C. LaStayo ◽  
D. J. Pierotti ◽  
J. Pifer ◽  
H. Hoppeler ◽  
S. L. Lindstedt
Keyword(s):  
Energy Demand ◽  
Size Composition ◽  
Muscle Size ◽  
Trained Group ◽  
Cross Sectional ◽  
Functional Changes ◽  
Cycle Ergometers ◽  
Muscle Adaptations ◽  
Fiber Size ◽  
Skeletal Muscle Adaptations

Lengthening (eccentric) muscle contractions are characterized by several unusual properties that may result in unique skeletal muscle adaptations. In particular, high forces are produced with very little energy demand. Eccentrically trained muscles gain strength, but the specific nature of fiber size and composition is poorly known. This study assesses the structural and functional changes that occur to normal locomotor muscle after chronic eccentric ergometry at training intensities, measured as oxygen uptake, that do not influence the muscle when exercised concentrically. Male subjects trained on either eccentric or concentric cycle ergometers for 8 wk at a training intensity starting at 54% and ending at 65% of their peak heart rates. The isometric leg strength increased significantly in the eccentrically trained group by 36%, as did the cross-sectional area of the muscle fiber by 52%, but the muscle ultrastructure remained unchanged. There were no changes in either fiber size, composition, or isometric strength in the concentrically trained group. The responses of muscle to eccentric training appear to be similar to resistance training.

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