Guilhem MOLLON
guilhem.mollon@insa-lyon.fr
Associate Professor
National Institute for Applied Sciences of Lyon
PhD, Civil Engineering, INSA Lyon
HDR, INSA Lyon
Guilhem MOLLON
guilhem.mollon@insa-lyon.fr
Associate Professor
National Institute for Applied Sciences of Lyon
PhD, Civil Engineering, INSA Lyon
HDR, INSA Lyon
Many tribological issues regularly appear in the aeronautical industry. During the studies performed at the LaMCoS on the topic, we essentially put our attention on two mechanical elements: bolted joints and sealing systems.
In the case of the bolted joints, the focus was put on a multiscale approach and on a dialog between experiments and simulations. We performed numerous simulations, both conventional (finite element modelling at the scale of the whole joint to determine the contact pressures) and non-conventional (dicrete element modelling at the scale of the threads in order to study the flows of third-body within the interfaces). These numerical results were then confronted to tribological observations (optical and electronic microscopy) and to vibratory tests with field measurements by digital image correlations. The purpose was to understand the life of the contact and its response to the vibratory loading.
Concerning the sealing joints, we dedicated our study on the assessment of the contact pressure at the interfaces between the joins and the mechanical parts, and on the consequences of this pressure on the local and global evolution of the contact.
Figure 1. Sketch of a bolted joint and of the threads interface.
Figure 2. SEM observation of the threads surfaces before and after tightening.
Figure 4. Digital Image Correlations performed during vibratory tests to determine the real contact dynamics.
Figure 5. Degradation aspects observed within the interface after vibratory loading.
Figure 8. Sketch of a sealing joint on a piston of a plane breaking systems.
Figure 9. Axisymmetric modelling of the sealing system.
Figure 3. Discrete modelling of the third body flow in the treads under vibratory loading.
Figure 6. Finite Element Modelling of the bolted joint.
Figure 7. Distribution of the contact pressures in the interface and comparison with experimental surface damage.
Figure 10. Contact pressures in the rod-seal interface at several epochs of a service cycle of the breaking system.
Figure 11. Surface aspects at different locations on the worn sealing joint, and qualitative correspondence with the numerical pressure profile.