A General Framework for the Experimental Characterization of Nonlinearities and its Application to a Laminated Assembly of an Electrical Motor

Manzato, Simone; Gazdagh, Zoltán; Vehovszky, Balázs; Ottaiano, Simona Anna

doi:10.4271/2022-01-0944

Cited by 2 publications

(3 citation statements)

References 13 publications

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“…These properties render it inappropriate for cyclic tests, but it does allow to perform dynamic analyses on the whole assembly. A similar method is used in [11], or in [16].…”

Section: Direct Measurement Using Bolts For Pretensionmentioning

confidence: 99%

A Method for Measuring Normal and Shear Stiffness of Laminate Stacks of Electric Motors

Szabó

Harrach²,

Feszty³

et al. 2023

Period. Polytech. Mech. Eng.

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Structural simulations of electric motors require precise material models. Laminate stacks that are made of several identical steel sheets are particularly challenging to simulate using FEA. The structural stiffness of laminate stacks usually follows transversal isotropic behavior. Measuring a complete laminate stack used in passenger cars is challenging due to its size and the high testing load needed to reach real loads experienced while in operation. A new method capable of performing such measurements is presented in this article, with the help of equipment normally used for testing structures used in civil engineering. Two sets of exemplary results are presented utilizing this measurement procedure, that were performed on a real automotive rotor laminate stack: axial compression stiffness from a cyclic test, and shear stiffness at various axial preload levels. In the axial compression load case, the loading and unloading curves form a hysteresis, that changes in every test cycle. Shear stiffness shows high dependance on the axial compression preload. After loading and unloading the stack with shear loads, significant plastic deformations remain.

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“…These properties render it inappropriate for cyclic tests, but it does allow to perform dynamic analyses on the whole assembly. A similar method is used in [11], or in [16].…”

Section: Direct Measurement Using Bolts For Pretensionmentioning

confidence: 99%

A Method for Measuring Normal and Shear Stiffness of Laminate Stacks of Electric Motors

Szabó

Harrach²,

Feszty³

et al. 2023

Period. Polytech. Mech. Eng.

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show abstract

“…For measuring static stiffness properties there were basically two types of procedures found by the authors. Examples for the first type of procedure can be found in [4] and [5]. It consists of two rigid steel plates, connected through bolts, with the specimen between them.…”

Section: The Quasi Static Experimentsmentioning

confidence: 99%

“…Various studies are available about the usage of dynamically obtained stiffness values, and a few examining static loading. [4], [5], [6], [7] No publications about performing the study on the same specimen after cyclic static loading has been found by the authors. In this research, static and dynamic experiments are performed on the same specimen -a real rotor lamination stack used in an automotive electric drive, to avoid altering the nonlinear behavior of the assembly.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of stiffness measurement methods for lamination stacks in electric machines

Szabó,

Gábor Gazdagh,

Vehovszky

2023

J. Phys.: Conf. Ser.

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With the increasingly strict global regulations on vehicle emissions, the demand for electromobility has risen due to its potential to reduce local emissions. However, designing an electric motor for use in passenger cars poses significant challenges. The e-motor should operate reliably in various climates with good mechanical and electrical characteristics, be lightweight, withstand repetitive thermal and structural loads, be cost-effective, and - last but not least - exhibit good noise and vibration properties. To meet these requirements, virtual testing through simulations has become the most efficient and economical approach, enabling the identification of weaknesses and unwanted behaviors before physical prototyping. This paper focuses on the testing of lamination stacks, a critical component of electric motors. Two methods of stiffness measurement for such parts are compared: static stiffness determination and dynamic analysis. The former involve compressing the specimen and measuring the force-displacement response, while dynamic method uses the restoring force surface method to obtain the stiffness and damping characteristics. The study highlights the importance of considering nonlinearity in stiffness measurements. The stiffness of lamination stacks varies depending on the pretension state, and a significant hysteresis exists between the loading and unloading curves. The paper discusses the experimental procedures for each method. The findings emphasize the necessity of accurate stiffness characterization for different applications, such as structural strength, modal analysis, dynamic analysis, and noise-vibration-harshness (NVH) studies. The research contributes to the development of electric machines by providing insights into effective stiffness measurement techniques for lamination stacks.

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A General Framework for the Experimental Characterization of Nonlinearities and its Application to a Laminated Assembly of an Electrical Motor

Cited by 2 publications

References 13 publications

A Method for Measuring Normal and Shear Stiffness of Laminate Stacks of Electric Motors

A Method for Measuring Normal and Shear Stiffness of Laminate Stacks of Electric Motors

Comparative analysis of stiffness measurement methods for lamination stacks in electric machines

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