Zouhair Chaib

Bio: Zouhair Chaib is an academic researcher from University of Toulouse. The author has contributed to research in topics: Bolted joint & Bearing (mechanical). The author has an hindex of 3, co-authored 3 publications receiving 140 citations.

3D Simplified Finite Elements Analysis of Load and Contact Angle in a Slewing Ball Bearing

Abstract: Bolted bearing connections are one of the most important connections in some industrial structures, and manufacturers are always looking for a quick calculation model for a safe design. In this context, all the analytical and numerical models reduce the global study to the study of the most critical sector. Therefore, the main inputs for these models are the maximal equivalent contact load and the corresponding contact angle. Thus, a load distribution calculation model that takes all the important parameters, such as the stiffness of the supporting structure and the variation in the contact angle, into consideration is needed. This paper presents a 3D finite element (FE) simplified analysis of load distribution and contact angle variation in a slewing ball bearing. The key element of this methodology, which is based on the Hertz theory, is modeling the rolling elements under compression by nonlinear traction springs between the centers of curvature of the raceways. The contact zones are modeled by rigid shells to avoid numerical singularities. Each raceway curvature center is coupled to the corresponding contact zone by rigid shells. The main contribution of this method is not only the evaluation of the contact loads with a relatively reduced calculation time but also the variation in the contact angle from the deformed coordinates of the curvature centers. Results are presented for several loading cases: axial loading, turnover moment, and a combined loading of axial force and turnover moment. The influence of the most important parameters such as the contact angle, the stiffness of the bearings, and the supporting structure is discussed. Finally, a preliminary experimental validation is conducted on a standard ball bearing. The results presented in this paper seem encouraging. The FE study shows an important influence of several parameters and a good correlation with experimental results. Consequently, this model can be extended to other types of slewing bearings such as roller bearings. Moreover, it can be implemented in complex industrial structures such as cranes and lifting devices to determine the corresponding load distributions and contact angles and, consequently, the most critical sector.

Screw behavior in large diameter slewing bearing assemblies: numerical and experimental analyses

Abstract: This paper investigates the behavior of large diameter bearing bolted joint in order to evaluate fatigue resistance of the screws. Based on experimental results, a sector of a slewing bearing is modeled using 3D finite elements. The model is built via hypothesis of sine-distributed efforts on the roller tracks. The simulations are carried out for the most loaded screw, which is located in the symmetry plane. Experimental measures on equipped screws are checked against numerical 3D simulations. This validates the numerical modeling method. Then the numerical model is used to evaluate the influence of several geometrical and physical parameters. The preload intensity reveals to be the major parameter. The bushes’ height affects load filtering and improves fatigue strength of the screws. The height of the mounting tubes smoothes potential stiff points. The friction coefficient between the ring and the mounting is investigated as well. Eventually, several observations are made which lead to design recommendations for fatigue sizing of the slewing bearing screwed joints.

Static and fatigue testing of open-hole and assembled composites based on long carbon fiber and a nylon matrix developed using fused deposition modelling: multiscale characterization of printed holes and machined holes

Abstract: The three-dimensional printing of long fiber composites was developed in recent years, and the mechanical behavior of the printed composites requires further investigation. The joining of this type of material requires a hole; and with reference to the available literature, the bearing strength requires investigation. In this context, three manufacturing processes were used for hole generation: direct printing, conventional drilling, and abrasive waterjet drilling (AWJ). The holes obtained by these manufacturing processes were characterized using X-ray tomography and a roughness system. Open-hole quasi-static and fatigue tests were used to assess the mechanical behavior of hole manufacturing on the tensile sections. Single-shear bearing tests yielded the same trend as that observed with open holes, where conventional drilling demonstrated higher performance than the printed and AWJ specimens. The absence of delamination and higher drilling temperature sealed the surface, thus limiting the influence of voids.

3D Simplified Finite Elements Analysis of Load and Contact Angle in a Slewing Ball Bearing

Abstract: Bolted bearing connections are one of the most important connections in some industrial structures, and manufacturers are always looking for a quick calculation model for a safe design. In this context, all the analytical and numerical models reduce the global study to the study of the most critical sector. Therefore, the main inputs for these models are the maximal equivalent contact load and the corresponding contact angle. Thus, a load distribution calculation model that takes all the important parameters, such as the stiffness of the supporting structure and the variation in the contact angle, into consideration is needed. This paper presents a 3D finite element (FE) simplified analysis of load distribution and contact angle variation in a slewing ball bearing. The key element of this methodology, which is based on the Hertz theory, is modeling the rolling elements under compression by nonlinear traction springs between the centers of curvature of the raceways. The contact zones are modeled by rigid shells to avoid numerical singularities. Each raceway curvature center is coupled to the corresponding contact zone by rigid shells. The main contribution of this method is not only the evaluation of the contact loads with a relatively reduced calculation time but also the variation in the contact angle from the deformed coordinates of the curvature centers. Results are presented for several loading cases: axial loading, turnover moment, and a combined loading of axial force and turnover moment. The influence of the most important parameters such as the contact angle, the stiffness of the bearings, and the supporting structure is discussed. Finally, a preliminary experimental validation is conducted on a standard ball bearing. The results presented in this paper seem encouraging. The FE study shows an important influence of several parameters and a good correlation with experimental results. Consequently, this model can be extended to other types of slewing bearings such as roller bearings. Moreover, it can be implemented in complex industrial structures such as cranes and lifting devices to determine the corresponding load distributions and contact angles and, consequently, the most critical sector.

Rolling-element bearing modeling: A review

Abstract: For the past several decades, significant efforts have been devoted to modeling and analysis of rolling-element bearings to aid in their design and application. This paper reviewed the modeling and analysis of rolling-element bearings with emphasis on single-row ball and roller bearings. The application of bearing models was reviewed as well along with illustrative results.