Optimal Rotor Shape Design of Asymmetrical Multi-Layer IPM Motors to Improve Torque Performance Considering Irreversible Demagnetization

M. S. Mirazimi,A. Kiyoumarsi,S. M. Madani 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

A study on the multi-objective optimization of Interior Permanent-Magnet Synchronous Motors (IPMSMs) with 2, 3, 4 and 5 flux barriers per magnetic pole, based on Genetic Algorithm (GA) is presented by considering the aspect of irreversible demagnetization. Applying the 2004 Toyota Prius single-layer IPMSM as the reference machine, the asymmetrical two-, three-, four- and five-layer rotor models with the same amount of Permanent-Magnets (PMs) is presented to improve the torque characteristics, i.e., reducing the torque pulsation and increasing the average torque. A reduction of the torque pulsations is achieved by adopting different and asymmetrical flux barrier geometries in each magnetic pole of the rotor topology. The demagnetization performance in the PMs is considered as well as the motor performance; and analyzed by using finite element method (FEM) for verification of the optimal solutions.

Numerical analysis of the combined aging and fillet effect of the adhesive on the mechanical behavior of a single lap joint of type Aluminum/Aluminum

S.M. Medjdoub,K. Madani,L. Rezgani,S. Mallarino,S. Touzain,R.D.S.G. Campilho 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.5

Bonded joints have proven their performance against conventional joining processes such as welding, riveting and bolting. The single-lap joint is the most widely used to characterize adhesive joints in tensile-shear loadings. However, the high stress concentrations in the adhesive joint due to the non-linearity of the applied loads generate a bending moment in the joint, resulting in high stresses at the adhesive edges. Geometric optimization of the bonded joint to reduce this high stress concentration prompted various researchers to perform geometric modifications of the adhesive and adherends at their free edges. Modifying both edges of the adhesive (spew) and the adherends (bevel) has proven to be an effective solution to reduce stresses at both edges and improve stress transfer at the inner part of the adhesive layer. The majority of research aimed at improving the geometry of the plate and adhesive edges has not considered the effect of temperature and water absorption in evaluating the strength of the joint. The objective of this work is to analyze, by the finite element method, the stress distribution in an adhesive joint between two 2024-T3 aluminum plates. The effects of the adhesive fillet and adherend bevel on the bonded joint stresses were taken into account. On the other hand, degradation of the mechanical properties of the adhesive following its exposure to moisture and temperature was found. The results clearly showed that the modification of the edges of the adhesive and of the bonding agent have an important role in the durability of the bond. Although the modification of the adhesive and bonding edges significantly improves the joint strength, the simultaneous exposure of the joint to temperature and moisture generates high stress concentrations in the adhesive joint that, in most cases, can easily reach the failure point of the material even at low applied stresses.

Comparative study of the resistance of bonded, riveted and hybrid assemblies; Experimental and numerical analyses

M.C.Ezzine,K. Madani,M. Tarfaou,S. Touzain,S. Mallarino 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.4

The objective of this work is to analyze by traction tests, the mechanical behavior of an assembly of type metal / metal by various assembly processes; bonding, riveting and hybrid, on the one hand to show the advantage of a hybrid assembly with respect to the other processes, and on the other hand, to analyze by the finite element method the distribution of the stresses in the various components of the structure and to demonstrate the effectiveness of the use of a hybrid assembly with respect to other processes. The number of rivets has been considered. The results show clearly that the value of the different stresses is reduced in the case of a hybrid junction and that the number of rivets in an assembly can be reduced by using a hybrid joint.

A new analytical approach for optimization design of adhesively bonded single-lap joint

M. Elhannani,K. Madani,M. Mokhtari,S. Touzain,X. Feaugas,S. Cohendoz 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.2

In this study the three-dimensional nonlinear finite element method was used to analyze the stresses distribution in the adhesive layer used to joint two Aluminum 2024-T3 adherends. We consider in this study the effect of different parameters witch directly affect the values of different stresses. The experimental design method is used to investigate the effects of geometrical parameters of the single lap joint in order to achieve an optimization of the assembly with simple lap joint. As a result, it can be said that both the geometrical modifications of the adhesive and adherends edge have presented a significant effect at the overlap edge thereby causing a decrease in peel and shear stresses. In addition, an analytical model is also given to predict in a simple but effective way the joint strength and its dependence on the geometrical parameters. This approach can help the designers to improve the quality and the durability of the structural adhesive joints.

Optimal Rotor Shape Design of Asymmetrical Multi-Layer IPM Motors to Improve Torque Performance Considering Irreversible Demagnetization

Mirazimi, M.S.,Kiyoumarsi, A.,Madani, Sayed M. The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

A study on the multi-objective optimization of Interior Permanent-Magnet Synchronous Motors (IPMSMs) with 2, 3, 4 and 5 flux barriers per magnetic pole, based on Genetic Algorithm (GA) is presented by considering the aspect of irreversible demagnetization. Applying the 2004 Toyota Prius single-layer IPMSM as the reference machine, the asymmetrical two-, three-, four- and five-layer rotor models with the same amount of Permanent-Magnets (PMs) is presented to improve the torque characteristics, i.e., reducing the torque pulsation and increasing the average torque. A reduction of the torque pulsations is achieved by adopting different and asymmetrical flux barrier geometries in each magnetic pole of the rotor topology. The demagnetization performance in the PMs is considered as well as the motor performance; and analyzed by using finite element method (FEM) for verification of the optimal solutions.

Serum Sclerostin Levels in Patients with Human Immunodeficiency Virus Infection and Their Association with Bone Turnover Markers and Bone Mineral Densitometry

Abdulrahman Y. Almansouri,Mohammed E. Abdulfatah,Omar H. Baaqil,Alaa A. Bakheet,Sarah A. Turki,Mamdouh M. Kotb,Alaa Althubaiti,Majed M. Almaghrabi,Abdulrahman M. Althubaiti,Badr M. Madani,Ali S. M. Ja 대한골대사학회 2016 대한골대사학회지 Vol.23 No.1

Background: The aim of the study was to compare serum sclerostin levels in human immunodeficiency virus (HIV)-infected patients and healthy controls, and to evaluate their relationship with bone turnover markers (BTM) and bone mineral density (BMD). Methods: We prospectively studied 33 HIV treatment-naive patients and 63 healthy individuals; match ed for age and sex. Serum sclerostin levels, BTM, BMD were measured. Viral load and cluster of differentiation 4 (CD4) levels were also assessed in HIV-infected patients. Results: The mean±standard deviation (SD) age of sample was 37.6±10.3 years (range, 19 to 59 years). Of the 96 subjects, 58 (60.4%) were male and 38 (39.6%) were female. Infection with HIV is associated with significant reduction in serum sclerostin levels (HIV-infected: 39.4±28.3 vs. non HIV: 76.6±15.7 pmol/L; P<0.001) and a decrease in BMD at femoral neck and lumbar spine compared to healthy controls. Sclerostin however was not correlated with BMD and was not related to age, generally a strong correlation. There were no significant correlations between sclerostin and BTM (P>0.05). Conclusions: These findings suggest that untreated HIV and the resulting immune deficiency and/or systemic inflammation could be an important regulator of serum sclerostin in this population.

Impact of bonding defect on the tensile response of a composite patch-repaired structure: Effect of the defect position and size

N. Kaddouri,K. Madani,S.CH. Djebbar,M. Belhouari,R.D.S.G. Campliho 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.6

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

Impact of composite patch on the J-integral in adhesive layer for repaired aluminum plate

Kaci, D. Ait,Madani, K.,Mokhtari, M.,Feaugas, X.,Touzain, S. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.6

The aim of this study is to perform a finite element analysis of the Von Mises stresses distribution in the adhesive layer and of the J-Integral for a damaged plate repaired by a composite patch. Firstly, we study the effect of the fiber orientation, especially the position of the layers that have orientation angle different of $0^{\circ}$ from the first layer which is in all cases of our study oriented at ($0^{\circ}$) on the J-Integral. Secondly, we evaluate the effects of the mechanical properties of the patch and the use of a hybrid patch on the reduction of stresses distribution and J-Integral. The results show clearly that the stacking sequence for the composite patch must be selected to absorb optimally the stresses from the damaged area and to position the various layers of the composite under the first layer whose fibers orientation will remain in all cases equal to $0^{\circ}$. The use of a hybrid composite reduces significantly the J-Integral and the stresses in both damaged plate and the adhesive layer.