Iker Heras

Iker Heras
University of the Basque Country | UPV/EHU · Mechanic Engineering

About

34
Publications
2,244
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234
Citations

Publications

Publications (34)
Preprint
Full-text available
Since Erich Franke produced the first wire race bearings in 1934, they have not been used profusely until these last years in applications such as computerized tomography, X-ray machines, wheels with direct drive... where low weight and inertia constraints are important. Accounting for the structural behaviour of the bearing, there exist a key phen...
Preprint
Full-text available
In wire bearings the rolling process occurs on raceways machined on steel wires, and the rings are made of light materials such as aluminium. This particular architecture provides both weight and inertia savings, but also significantly different behaviour with respect to conventional bearings. For this reason, specific design and analysis tools mus...
Preprint
Full-text available
This work introduces a methodology for the calculation of the load distribution in four-point contact slewing bearings considering ball preload, manufacturing errors and ring flexibility. The model is built by the formulation and minimization of the potential energy of the bearing. Comparing with the rigid rings assumption, the results show that ri...
Preprint
Full-text available
Since wire bearings were patented in 1936, they have been used in applications where weight saving is a key aspect. Nevertheless, little work can be found in literature regarding their structural behaviour. In order to predict how a wire bearing reacts under load, the most feasible way is to model and analyse it via Finite Elements (FE). However, t...
Preprint
Full-text available
Several factors can cause leakages in a bolted flange connection, external loads being the most important one. External loads such as those produced by misalignment introduce an external axial load combined with a bending moment which could lead to either an excessive compression of the gasket and its subsequent crushing, and/or a separation of the...
Article
Full-text available
This manuscript presents an innovative methodology for the assessment of the friction torque of ball slewing bearings. The methodology aims to overcome the limitations of state-of-the-art approaches, especially when the friction torque is conditioned by the preload of the balls. To this end, the authors propose to simulate the preload scatter when...
Chapter
Wire-race bearings are a special type of bearings where rolling elements run over steel wires embedded within the rings, allowing the use of lighter materials for the latter. In previous research works, and motivated by the capabilities of these components and the lack of bibliography on the matter, the authors developed different approaches to sim...
Article
Wire race slewing bearings are a special type of bearings where rolling elements run over a race-shaped steel wire embedded into the rings. In contrast to conventional slewing bearings, no efficient FE modelling strategies have been proposed. In this sense, an analytical formulation to simulate the roller-wire-ring subset was developed in a previou...
Article
Wire bearings are becoming popular these days in applications such as defence, robotics, medical devices or shipping industry. They provide weight and inertia reductions, good shock load and vibration absorbing capacity, constant torque and low maintainance. Despite all the benefits of this kind of bearings, there are few wire race bearing manufact...
Article
When a bolt is tightened, significant dispersion between the target preload and the obtained preload may be found. As a consequence, when bolts are subsequently tightened during the assembly process of a bolted joint, the dispersion is propagated leading to a higher scatter in the final bolt load distribution. In this sense, the final bolt loads ma...
Article
Since wire bearings were patented in 1936, they have been used in applications where weight saving is a key aspect. Nevertheless, little work can be found in literature regarding their structural behaviour. In order to predict how a wire bearing reacts under load, the most feasible way is to model and analyse it via Finite Elements (FE). However, t...
Article
Since Erich Franke produced the first wire race bearings in 1934, they have not been used profusely until these last years in applications such as computerized tomography, X-ray machines, wheels with direct drive… where low weight and inertia constraints are important. Accounting for the structural behaviour of the bearing, there exist a key phenom...
Article
This work introduces a methodology for the calculation of the load distribution in four-point contact slewing bearings considering ball preload, manufacturing errors and ring flexibility. The model is built by the formulation and minimization of the potential energy of the bearing. Comparing with the rigid rings assumption, the results show that ri...
Chapter
Wire-race bearings are a non-conventional type of bearings where the rolling process takes place over a race shaped in a wire. This design allows building the rings with lighter materials and innovative ring designs. Despite the wide range of applications where wire-race bearings can be the best option, no specific analysis tools have been develope...
Chapter
Nowadays, dental implant fatigue tests are commonly performed in direct stress fatigue test benches. Even though the accuracy of these machines is very high, they can only test one specimen simultaneously. Besides, taking into account that each test may last several days, a dental implant fatigue characterization may become a very costly task. Furt...
Chapter
This work proposes an approach to calculate the load distribution among balls in a four-point contact slewing bearing considering manufacturing errors and ring stiffness. The model is established upon the formulation and minimization of the potential energy of the system. Calculations are done for a particular bearing considering different assumpti...
Article
Full-text available
The stiffness of yaw and pitch slewing bearings has a critical influence on the structural behaviour of wind turbine generators. Thus, it is commonly required by designers for their simulations to estimate deformations and select the most suitable bearing for their working conditions in preliminary design stages. In this work, a design of experimen...
Article
In wire bearings the rolling process occurs on raceways machined on steel wires, and the rings are made of light materials such as aluminium. This particular architecture provides both weight and inertia savings, but also significantly different behaviour with respect to conventional bearings. For this reason, specific design and analysis tools mus...
Conference Paper
A lot of effort is put to achieve bolt preload uniformity during the assembly process of offshore bolted joint connections resulting in potentially high economic costs and project delays. The complexity of this operation is due to the effect of the elastic interaction between the different joint elements which causes load variations of adjacent bol...
Article
Several factors can cause leakages in a bolted flange connection, external loads being the most important one. External loads such as those produced by misalignment introduce an external axial load combined with a bending moment which could lead to either an excessive compression of the gasket and its subsequent crushing, and/or a separation of the...
Conference Paper
In this work, a superelement-based model is developed to study bolt load variations and gasket stress distribution during tightening sequences, in order to avoid damages in the assembly and achieve uniform gasket stress distribution. Besides, this model can also be used to study the response of gasketed joints under internal and external loads. To...
Conference Paper
For pressure vessels gasketed joints, obtaining a uniform bolt load distribution is mandatory in order to ensure leak-free service of the joint. However, due to the elastic interaction phenomenon, it is difficult to achieve a uniform bolt load distribution. To address this difficulty, standards recommend tightening sequences that have shown good pe...
Article
This work outlines a procedure for the determination of the interferences between balls and raceways in four contact point slewing bearings due to manufacturing errors. The procedure is applied to a particular case and finite element analyses are performed for the friction torque calculation, considering different preloads. The results are used to...
Article
The friction torque is a key parameter in the design of slewing bearings. The most challenging issue in its calculation resides in the modelling of rolling element contact mechanics. In this manuscript two models for the friction torque calculation are compared: a Finite Element model and the analytical model proposed by Leblanc and Nelias. The las...
Chapter
This work proposes a procedure for the determination of the interferences between balls and raceways in four-contact-point slewing bearings due to manufacturing errors. The procedure is applied to a particular case and finite element analyses are performed for the friction moment calculation, considering different preloads. The results are used to...
Article
This work presents a model to assess the equivalent load for self-lubricating radial spherical plain bearings under combined loads, based on the study of the interference field. Using an algorithm based on the model, a methodology has been created to estimate failure load combinations. The results, validated via Finite Element Analysis, are present...

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