The role of a thermally sprayed CuNiIn underlayer in the durability of a dry-film lubricant system in fretting – A phenomenological model

Abstract

Dry film lubricant coatings (DFL) are employed to reduce friction and damage in highly loaded contacts. Metallic underlayers, e.g. CuNiIn, can be beneficial however, there is no detailed explanation of the mechanism. This work investigates the effect of CuNiIn on fretting of a MoS2-based DFL in a cylinder-on-flat contact with a fretting amplitude of 300 µm. Two test types were run: 1. DFL without CuNiIn; 2. DFL on the cylindrical sample and DFL with CuNiIn underlayer on the flat sample. The CuNiIn increased the system's durability. A phenomenological model highlighting the important low friction and highly wear resistant interfacial material is developed. The increased durability is ascribed to the high roughness of the CuNiIn onto which the DFL was deposited.

The Data-Driven Surrogate Model-Based Dynamic Design of Aeroengine Fan Systems

“…The level of dissipating nonlinearity in the blade system due to the contact friction is dependent on the parameters of  , T K , 0 N and the input force magnitude 0 F , and the effects of these design parameters on the system output responses. For example, the effect of an increase of the friction coefficient  from 0.1 to 0.9 [6,7] with a fixed T K , 0 N and 0 F , are as illustrated in Fig. 3.…”

“…Based on the previous experimental studies in [6,7], the considered ranges of values of the design parameters of interest are taken as Because there are 4 design parameters, if each parameter has 5 different values to test, there is a total number of 625 tests for a full scale design, which is a large amount of tests for either FE simulation or experiment. In order to identify the NP-ARX model by using less testings, in this study, the UD method is applied to determine t N number of tests with the design parameters uniformly distributed over the space as formulated by (8).…”

“…This way of energy dissipation in the fan system can be optimized by applying suitable dry film lubricant coatings on the blade root as it can effectively change the contact conditions by reducing the frictional coefficient [6]. The main purpose of applying the coating is to address the problem with fretting fatigue by reducing the tangential contact stress in joint interface [7]. The solid lubricant Molydag 254 is mostly used, which consists of MoS2 powder, carbon and other solid lubricants in a thermosetting phenolic resin [6].…”

“…A simplified fan bladed disc system with contact friction Jenkins elements are considered as the test case. The effect of the coating on the contact surface is represented by the contact parameters in the Jenkins element based on the experiments conducted in [6,7]. The NP-ARX model based design of a fan system involves tree steps which are (1) Collection of the high fidelity model/experiment generated system input and output data under different choices of the design parameters; (2) Determination of the NP-ARX model of the gas turbine fan blade with coated roots; and (3) Design the root coating parameters using the FRF of the NP-ARX model.…”

Reduced Order Method Based on an Adaptive Formulation and its Application to Fan Blade System With Dovetail Joints

“…Such a failure very likely occurs in the dovetail joint due to the fretting fatigue [5,6]. As a result, the contact interfaces are always protected by the dry lubricant film coating to improve the fatigue life of the fan blade system [7]. The solid lubricant Molydag 254 is mostly used, which consists of MoS2 powder, carbon and other solid lubricants in a thermosetting phenolic resin [6].…”