A limited and extendable master thesis is representing the first step in the experimental substructuring of an A600 wind turbine. Additional masses have been designed, manufactured and added to the sub components for the laboratory experimental tests. Further preparations for dynamic experimental tests have been described and implemented. Vibrational tests of a modified wind turbine blade have been made using the Leuven Measurements System (LMS) for excitations and data acquisition purposes. The theory of frequency response function based substructuring applied on the wind turbine blade model is demonstrated. The theory and an example of a Matlab coded spring-mass system, an experimental model of a wind turbine blade and FRFs stemming from measurements are reported.

Submitted by VIVIANE CASSOL MARQUES null (vivicm@gmail.com) on 2018-01-19T17:29:04Z No. of bitstreams: 1 DefesaTese_Viviane_Cassol_Marques_LibraryVersion.pdf: 2942887 bytes, checksum: f212fcfebf6c7edc3efed2df80579420 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-01-19T18:31:18Z (GMT) No. of bitstreams: 1 marques_vc_dr_ilha.pdf: 2942887 bytes, checksum: f212fcfebf6c7edc3efed2df80579420 (MD5) / Made available in DSpace on 2018-01-19T18:31:18Z (GMT). No. of bitstreams: 1 marques_vc_dr_ilha.pdf: 2942887 bytes, checksum: f212fcfebf6c7edc3efed2df80579420 (MD5) Previous issue date: 2017-12-12 / Grandes estruturas, como aviões, navios e até mesmo sistemas de refrigeração, que possuem muitos componentes podem ser substruturados, com o intuito de agilizar e facilitar o cálculo da transmissão vibratória entre seus componentes. Existem diversas formas e domínios em que esta substruração pode ser realizada, sendo a utilizada nesta tese a substruturação no domínio da frequência utilizando para o cálculo as mobilidades medidas nos pontos de acoplamento dos componentes. Esta tese se concentra na substruturação de sistemas dinâmicos que possuem áreas flexíveis de contato como o que ocorre no acoplamento de amortecedores de borracha em sistemas vibratórios, sendo que para estes casos foi verificado que os métodos de substruturação mais usuais não apresentaram bons resultados para frequências superiores a primeira frequência natural do sistema completo, mesmo quando utilizados vários pontos de acoplamento no amortecedor de borracha. Utilizando o cálculo do comprimento de onda em diferentes materiais, neste caso o aço e a borracha, foi possível determinar uma relação entre a distância dos pontos de acoplamento e o comprimento de onda em que a metodologia de substruturação apresenta resultados acurados. Devido a estas limitações dos métodos de substruração, quando acoplamentos flexíveis existem nos subsistemas considerados, uma nova forma de substruração foi apresentada a qual mostrou resultados muito melhores, especialmente quando comparados com os resultados do sistema completo quando substruturado no acoplamento flexível. / Large structures, such as airplanes, ships and even refrigeration systems, which have many components, can be substructured in order to speed up and facilitate the process of calculating the vibratory transmission between the system components. There are several methods and domains in which the substructuring can be done. In this thesis the substructuring method in the frequency domain is chosen to do the calculations, with the mobilities measured at the coupling points of the components. This thesis focuses on the substructuring of dynamic systems that have flexible distributed connections, such as those which occur in the coupling with rubber isolators in vibratory systems. For these cases, the most usual substructuring methods are shown not to give good results for frequencies higher than the first natural frequency of the complete system, even when several coupling points are used for the rubber isolator. Using the calculation of the flexural wavelength in different materials, in this case steel and rubber, it is possible to determine a relationship between the distance of the coupling points within the isolator and the wavelengths of the component materials, at which the substructuring methodology gives accurate results. Due to these limitations of current substructuring methods, when soft flexible couplings exist in the subsystems, a new substructuring approach is presented, and is shown to really improve the results, especially when compared to the when the complete system is substructured at the flexible coupling.

Orientador: Michael John Brennan / Resumo: Grandes estruturas, como aviões, navios e até mesmo sistemas de refrigeração, que possuem muitos componentes podem ser substruturados, com o intuito de agilizar e facilitar o cálculo da transmissão vibratória entre seus componentes. Existem diversas formas e domínios em que esta substruração pode ser realizada, sendo a utilizada nesta tese a substruturação no domínio da frequência utilizando para o cálculo as mobilidades medidas nos pontos de acoplamento dos componentes. Esta tese se concentra na substruturação de sistemas dinâmicos que possuem áreas flexíveis de contato como o que ocorre no acoplamento de amortecedores de borracha em sistemas vibratórios, sendo que para estes casos foi verificado que os métodos de substruturação mais usuais não apresentaram bons resultados para frequências superiores a primeira frequência natural do sistema completo, mesmo quando utilizados vários pontos de acoplamento no amortecedor de borracha. Utilizando o cálculo do comprimento de onda em diferentes materiais, neste caso o aço e a borracha, foi possível determinar uma relação entre a distância dos pontos de acoplamento e o comprimento de onda em que a metodologia de substruturação apresenta resultados acurados. Devido a estas limitações dos métodos de substruração, quando acoplamentos flexíveis existem nos subsistemas considerados, uma nova forma de substruração foi apresentada a qual mostrou resultados muito melhores, especialmente quando comparados com os resultados do sistema completo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Large structures, such as airplanes, ships and even refrigeration systems, which have many components, can be substructured in order to speed up and facilitate the process of calculating the vibratory transmission between the system components. There are several methods and domains in which the substructuring can be done. In this thesis the substructuring method in the frequency domain is chosen to do the calculations, with the mobilities measured at the coupling points of the components. This thesis focuses on the substructuring of dynamic systems that have flexible distributed connections, such as those which occur in the coupling with rubber isolators in vibratory systems. For these cases, the most usual substructuring methods are shown not to give good results for frequencies higher than the first natural frequency of the complete system, even when several coupling points are used for the rubber isolator. Using the calculation of the flexural wavelength in different materials, in this case steel and rubber, it is possible to determine a relationship between the distance of the coupling points within the isolator and the wavelengths of the component materials, at which the substructuring methodology gives accurate results. Due to these limitations of current substructuring methods, when soft flexible couplings exist in the subsystems, a new substructuring approach is presented, and is shown to really improve the results, especially when compared to the when the complete sy... (Complete abstract click electronic access below) / Doutor

This work describes the creation of detailed FEM models of the selected area. Primarily is focused on the process of creating a detailed FEM model of the part of airplane using the static condensation. This work also contains a description of the process stress analysis of part of the fuselage of the airplane EV-55 Outback.

No description available.

In dynamic substructuring, a complex structure is divided into multiple substructures that can be analysed individually and these individual component responses are coupled together to obtain the global response of the whole structure. Dynamic substructuring can be performed on substructure models that are identified either experimentally or analytically. For dynamic substructuring to be successful, it is very essential to have the precise information of the connection points or the interfaces between the substructures. The method has been extensively used with analytical models in most of the available standard finite element software packages where the information about all degrees of freedom is known. However, it is difficult to get the information about all connection degrees of freedom from the measurements and experimental substructuring is thus limited in its use compared to analytical substructuring. In order to overcome these difficulties, the Transmission Simulator method commonly also known as Modal Constraints for Fixture and Subsystem method can be used. In this method, an additional fixture called Transmission Simulator which is available both physically and analytically, is attached to the substructures at the interfaces and their respective responses are measured. The substructures could be analytical as well as experimental. The coupling is done by constraining the transmission simulator on the substructures to have the same motion and the effect of the transmission simulator is later removed from the coupled structure by subtracting the analytical transmission simulator model. This method has been successfully implemented for Component Mode Synthesis and Frequency Based Substructuring for structures with multiple connection points at a single location. In this thesis work, frequency response function based experimental–analytical dynamic substructuring using the transmission simulator is performed on a rear subframe and rear differential unit assembly of a Volvo XC90 car where the differential unit is connected to the subframe at three locations. The aim of this work is to verify the Transmission Simulator Method for multiple location connection points using the frequency response functions and build confidence on the methodology in order to be used for future work at Volvo Car Corporation.

Dynamic Substructuring is a powerful tool for simplification of the analysis of complex structures and it has been well established along the years in analytical calculations by means of the Craig-Bampton technique. Recently, a new branch of substructuring, the Experimental Dynamic Substrucuring, appeared as a promising field of research for the engineering community. This area presents several intrinsic difficulties, evincing a need to develop the traditional substructuring methods towards obtaining better results using the experimental approach. In this scenery, the Transmission Simulator technique emerges as an instrument for potential improvement of the achieved results. This work represents a study on the use of the Transmission Simulator technique in the analysis of an Ampair A600 wind turbine blade subjected to loads at the interface to the hub, and it is a part of the benchmarking studies of SEM (Society of Experimental Mechanics). The work consisted of collecting experimental data via vibration tests of a single blade connected to different sizes of transmission simulators. After that, a mathematical representation of the blade was obtained via subtraction of the effect of the transmission simulators via substructuring technique. The computed model was subsequently coupled to a model of the remainder of the wind turbine (the hub plus two blades), and the results were compared to data acquired in tests of the whole assembly. The final findings did not reflect the theory prospects and further investigation is necessary to evaluate the effectiveness of the used methodology.

Complex systems can be divided into simpler substructures. Determining the properties of each subcomponent by experimental procedures is practical and can serve to verify or calibrate finite element models. In this work, an existing model of a wind turbine blade was improved by use of experimental data. Such a blade is a subpart of a complete wind turbine. For calibration purpose, several material tests were made in order to determine the stiffness and mass properties. Later on, vibration tests of the blades were conducted and compared with simulation results of the improved model. Geometry variability within sets of blades was also studied. The blade twist angles and the center of gravity positions were found to vary moderately, which accounts for differences in blades’ dynamic behavior. Correlations between experimental data and analytical model results were very high for the first eight modeshapes. That is, according to the Model Assurance Criterion the calibrated model achieves a high-quality representation of reality. However, torsional modes in the computer model occur at a higher frequency than the experimental ones. Substructuring of the turbine allows the blades to be modeled and validated independently of the other substructures and can later be incorporated into a complete model of the turbine.

This study presented a substructure based parallel linear solution framework for the static analysis of linear structural engineering problems having multiple loading conditions. The framework was composed of two separate programs designed to work on PC Clusters having the Windows operating system. The first program was responsible for creating the optimum substructures for the parallel solution and first partitioned the structure in such a way that the number of substructures was equal to the number of processors. Then, the estimated condensation time imbalance of the initial substructures was adjusted by iteratively transferring nodes from the substructures with slower estimated condensation times to the substructures with faster estimated condensation times. Once the final substructures were created, the second program started the solution. Each processor assembled its substructures stiffness matrix and condensed it to the interface with other substructures. The interface problem was solved by a parallel variable band solver. After computing the interface unknowns, each processor calculated the internal displacements and element stresses or forces. Examples which illustrate the applicability and efficiency of this approach were also presented. In these examples, the number of processors was varied from one to twelve to demonstrate the performance of the overall solution framework.

The subject of this thesis is an extension of a two-dimensional, axisymmetric, Timoshenko-beam finite-element rotordynamic code to include a three-dimensional non-axisymmetric solid-element casing model. Axisymmetric beams are sufficient to model rotors. Spring and damper forces provide the interface between the rotor and its casing and capture the dynamics of the full model. However, axisymmetric beams limit the modeling of real-case machine structures, where the casing is not axisymmetric. Axisymmetric and non-axisymmetric 3D finite element casing structures are modeled. These structures are then reduced using a technique called substructuring. Modal equations are developed for axisymmetric and non-axisymmetric casing models. In a 3D non-axisymmetric model, structural dynamics modes can be modeled by lateral modes in two orthogonal planes. Modal information of the complex 3D casing structures are generated, and then incorporated into the 2D code after a series of pre-processing steps. A reduction method called Component Mode Synthesis (CMS) is used to reduce the large dimensionality involved in calculation of rotordynamic coefficients. The results from the casing structures are merged with the rotor model to create a combined rotor-casing model. The analysis of the combined structure shows that there is a difference in the natural frequencies and unbalance response between the model that uses symmetrical casing and the one that uses non-axisymmetric casing. XLTRC2 is used as an example of a two-dimensional axisymmetric beam-element code. ANSYS is used as a code to build three-dimensional non-axisymmetric solid-element casing models. The work done in this thesis opens the scope to incorporate complex non-axisymmetric casing models with XLTRC2.