An Aeromechanical Screening Tool for Turbine Blades

2017 ◽  
Author(s):  
Suryarghya Chakrabarti ◽  
Andrew Grafitti ◽  
Brian Potter
Keyword(s):  
Structural Design ◽  
Screening Tool ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Shell Element ◽  
Element Model ◽  
Design Tool ◽  
Frequency Error ◽  
Concept Design ◽  
Gas Turbine Blades

A design tool has been developed to calculate the natural frequencies of shrouded or unshrouded gas turbine blades in seconds to allow designers to perform aeromechanical frequency avoidance checks in the early concept design phase. The tool derives its inputs from a pitch-line aerodynamic calculation and a 1D structural design tool and uses a NACA-based airfoil section generator to create the airfoil sections. It then generates a shell-element based finite element model for the blade and disk sector, performs a pre-stressed modal analysis, and ranks the blades according to their frequency margins with specified aerodynamic drivers. Validation studies comparing this simplified model to high-fidelity solid element FEA models show the frequency error to be below 5% for most cases. The speed of this tool allows for frequency assessment of thousands of designs in a few hours allowing the designer to perform large spacefilling DoEs and select a flow path which minimizes the chances of fundamental mode crossings in later design stages..

Quick Aeromechanical Assessment of Turbine Blades Based on Shell Element Based Models

2014 ◽  
Author(s):  
Suryarghya Chakrabarti ◽  
Letian Wang ◽  
K. M. K. Genghis Khan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Computation Time ◽  
Shell Element ◽  
Element Model ◽  
Shell Elements ◽  
Barrier Coating ◽  
Order Of Magnitude

A fast finite element model based tool has been developed to calculate the natural frequencies of fundamental modes of cooled gas turbine bladed disk assemblies during conceptual design. The tool uses shell elements to model the airfoil, shank, and disk, and achieves order of magnitude reduction in computation time allowing exploration of a wide design space at the preliminary design stages. The analysis includes prestress effects due to centrifugal loading and approximate temperature loading on the parts. Sensitivity studies are performed to understand the relative impact of design features such as airfoil internal geometry, bond coat, and thermal barrier coating on the system natural frequencies. Critical features are selected which need to be modeled to get an accurate natural frequency estimate. The results obtained are shown to be within 5% of the frequencies obtained from a full-fidelity finite element model. A case study performed on seven blade designs illustrates the use of this tool for quick aeromechanical assessment of a large number of designs.

Methods of Incorporating Design-for-Production Considerations into Concept Design Investigations

1990 ◽  
Vol 6 (02) ◽  
pp. 69-80
Author(s):  
H. S. Bong ◽  
William Hills ◽  
John B. Caldwell
Keyword(s):  
Production Process ◽  
Production Technology ◽  
Structural Design ◽  
Design Tool ◽  
Design Model ◽  
Interactive Graphics ◽  
Concept Design ◽  
Construction Process ◽  
Total Cost ◽  
Work Content

The paper describes a method of incorporating knowledge and data of the production process into a concept design model in a way which provides a flexible and powerful structural design tool. Interactive graphics is shown to be a useful design aid when defining geometry and scantlings particularly when combined with a database of information on standardization, build methods and production technology. An effective method of assessing work content is presented in which man-hours are assessed for each phase in the construction process, that is, preparation, fabrication and erection. The total build cost, including labor, material and overhead, is used as the criterion in a series of studies which demonstrate the application of the method to concept design and which show the sensitivity of total cost to changes in various parameters of design and production.

Efficient structural analysis of gas turbine blades

2018 ◽  
Vol 90 (9) ◽  
pp. 1305-1316
Author(s):  
Timo Rogge ◽  
Ricarda Berger ◽  
Linus Pohle ◽  
Raimund Rolfes ◽  
Jörg Wallaschek
Keyword(s):  
Structural Analysis ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Element Model ◽  
Gas Turbine Blade ◽  
Quality Of Results ◽  
Content Type ◽  
Gas Turbine Blades

Purpose The purpose of this study a fast procedure for the structural analysis of gas turbine blades in aircraft engines. In this connection, investigations on the behavior of gas turbine blades concentrate on the analysis and evaluation of starting dynamics and fatigue strength. Besides, the influence of structural mistuning on the vibration characteristics of the single blade is analyzed and discussed. Design/methodology/approach A basic computation cycle is generated from a flight profile to describe the operating history of the gas turbine blade properly. Within an approximation approach for high-frequency vibrations, maximum vibration amplitudes are computed by superposition of stationary frequency responses by means of weighting functions. In addition, a two-way coupling approach determines the influence of structural mistuning on the vibration of a single blade. Fatigue strength of gas turbine blades is analyzed with a semi-analytical approach. The progressive damage analysis is based on MINER’s damage accumulation assuming a quasi-stable behavior of the structure. Findings The application to a gas turbine blade shows the computational capabilities of the approach presented. Structural characteristics are obtained by robust and stable computations using a detailed finite element model considering different load conditions. A high quality of results is realized while reducing the numerical costs significantly. Research limitations/implications The method used for analyzing the starting dynamics is based on the assumption of a quasi-static state. For structures with a sufficiently high stiffness, such as the gas turbine blades in the present work, this procedure is justified. The fatigue damage approach relies on the existence of a quasi-stable cyclic stress condition, which in general occurs for isotropic materials, as is the case for gas turbine blades. Practical implications Owing to the use of efficient analysis methods, a fast evaluation of the gas turbine blade within a stochastic analysis is feasible. Originality/value The fast numerical methods and the use of the full finite element model enable performing a structural analysis of any blade structure with a high quality of results.

Analysis of Free Vibration Characteristics and Mode Shapes of a Semi-Submersible Platform

2011 ◽  
Author(s):  
Jonas W. Ringsberg ◽  
Per Ernholm ◽  
Love Hogstro¨m
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Fundamental Frequency ◽  
Natural Frequencies ◽  
Wave Spectrum ◽  
Shell Element ◽  
Element Model ◽  
Beam Element ◽  
Resonance Frequencies ◽  
Exciting Wave

The current investigation presents a global natural frequency and mode shape analysis of a semi-submersible platform. The purpose is to evaluate the separation in frequency between the semi-submersible’s global natural frequencies and the exciting wave spectrum. Two types of finite element models are compared: a beam element model and a shell element model. The main differences in the models are the level of resolution in details and model complexity. It is shown that both beam and shell element models can be used for the analysis. However, the beam element model is recommended for a first approximate assessment of the fundamental natural frequency and the interval/spectrum of global resonance frequencies compared to the wave spectrum. The shell element model is recommended when a more thorough analysis is required. In addition, the natural frequencies of the semi-submersible are calculated for free vibration in air. The fundamental frequency was 1.9 Hz for the beam element model and 1.5 Hz for the shell element model. When weights corresponding to a submerged structure in operation mode are considered, including the effects of added mass, the fundamental frequency for the first mode using the beam element model was decreased to 0.7 Hz, and to 0.6 Hz when using the shell element model. When compared to the DNV world wave spectrum’s highest frequency of 0.29 Hz it is concluded that the natural frequencies of the semi-submersible are at a sufficient distance from the exciting wave spectrum.

scholarly journals Concept Calculation Tool for Dynamics of Generator Set Common Baseframe

2017 ◽  
Vol 50 (3) ◽  
pp. 353-356 ◽  
Author(s):  
Johannes Heilala ◽  
Teemu Kuivaniemi ◽  
Juho Könnö ◽  
Tero Frondelius
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequency ◽  
Element Model ◽  
Simulation Software ◽  
Design Tool ◽  
Vibration Response ◽  
Model Generation ◽  
Concept Design ◽  
Common Base

The Natural frequency and vibration response calculation process of a generator set was automatized so that it can be used in a generator set common base frame concept design. The implementation of automatization was to be done so that no profound knowledge about the finite element method is needed to execute calculations and that computation times are short. Substructuring is used for certain parts of the generator set model to reduce the computation times for more a efficient concept design process. The common base frame concept design is implemented to the process by using a design tool in which the finite element model generation from parametric geometry is automatized. Generator set finite element model generation, natural frequency and vibration response calculations and post-processing of analysis results were implemented by developing a calculation tool for this purpose. The calculation tool is an independent application that uses Abaqus simulation software to execute analyses.

Quick Method for Aeroelastic and Finite Element Modeling of Wind Turbine Blades

2014 ◽  
Author(s):  
Jeffrey Bennett ◽  
Robert Bitsche ◽  
Kim Branner ◽  
Taeseong Kim
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Element Model ◽  
Wind Turbine Blades ◽  
Quick Method ◽  
Cross Sectional ◽  
Aeroelastic Simulations

In this paper a quick method for modeling composite wind turbine blades is developed for aeroelastic simulations and finite element analyses. The method reduces the time to model a wind turbine blade by automating the creation of a shell finite element model and running it through a cross-sectional analysis tool in order to obtain cross-sectional properties for the aeroelastic simulations. The method utilizes detailed user inputs of the structural layup and aerodynamic profile including ply thickness, orientation, material properties and airfoils to create the models. After the process is complete the user has two models of the same blade, one for performing a structural finite element model analysis and one for aeroelastic simulations. Here, the method is implemented and applied to reverse engineer a structural layup for the NREL 5MW reference blade. The model is verified by comparing natural frequencies to the reference blade. Further, the application to aeroelastic and structural evaluations is demonstrated. Aeroelastic analyses are performed, and predicted fatigue loads are presented. Extreme loads from the aeroelastic simulations are extracted and applied onto the blade for a structural evaluation of the blade strength. Results show that the structural properties and natural frequencies of the developed 5MW blade match well with the reference blade, however the structural analysis found excessive strain at 16% span in the spare caps that would cause the blade to fail.

Modeling of Welded Joints in a Pyramidal Truss Sandwich Panel Using Beam and Shell Finite Elements

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Ke Yuan ◽  
Weidong Zhu
Keyword(s):  
Welded Joints ◽  
Natural Frequencies ◽  
Welded Joint ◽  
Shell Element ◽  
Element Model ◽  
Modal Parameters ◽  
Main Step ◽  
Solid Element ◽  
Pyramidal Truss ◽  
Elastic Modes

Abstract Pyramidal truss sandwich panels (PTSPs) are widely used in engineering structures and their face sheets and core parts are generally bonded by the welding process. A large number of solid elements are usually required in the finite element (FE) model of a PTSP with welded joints to obtain its accurate modal parameters. Ignoring welded joints of the PTSP can save many degrees of freedom (DOFs), but significantly change its natural frequencies. This study aims to accurately determine modal parameters of a PTSP with welded joints with much fewer DOFs than those of its solid element model and to obtain its operational modal analysis results by avoiding missing its modes. Two novel methods that consider welded joints as equivalent stiffness are proposed to create beam-shell element models of the PTSP. The main step is to match stiffnesses of beam and shell elements of a welded joint with those of its solid elements. Compared with the solid element model of the PTSP, its proposed models provide almost the same levels of accuracy for natural frequencies and mode shapes for the first 20 elastic modes, while reducing DOFs by about 98% for the whole structure and 99% for each welded joint. The first 14 elastic modes of a PTSP specimen that were measured without missing any modes by synchronously capturing its two-faced vibrations through use of a three-dimensional scanning laser vibrometer (SLV) and a mirror experimentally validate its beam-shell element models created by the two proposed methods.

Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys

1983 ◽  
Vol 41 ◽  
pp. 250-251
Author(s):  
E. F. Koch ◽  
E. L. Hall ◽  
S. W. Yang
Keyword(s):  
Alloy Composition ◽  
Volume Fraction ◽  
Lattice Mismatch ◽  
Turbine Blades ◽  
Eutectic Alloys ◽  
Alloy Matrix ◽  
X Ray ◽  
Gas Turbine Blades ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.

UDIMET L-605

Alloy Digest ◽  
2004 ◽  
Vol 53 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Gas Turbine ◽  
Oxidation Resistance ◽  
Turbine Blades ◽  
Heat Treating ◽  
Gas Turbine Blades ◽  
Temperature Performance

Abstract Udimet L-605 is a high-temperature aerospace alloy with excellent strength and oxidation resistance. It is used in applications such as gas turbine blades and combustion area parts. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: CO-109. Producer or source: Special Metals Corporation.

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