Comparative study: Impact of Ball burnishing and shot peening Process on Aluminium 2024 alloy

Compressive residual stress is the major aspect in the extension of the fatigue life of aeroengine components. In this study, a modified burnishing surface treatment and conventional shot peening process was used was proposed to improve surface integrity characteristics such as surface finish, hardness, and stable, advantageous compressive residual stress in turned Cylindrical Aluminum 2024Specimen. In burnishing process, a rolling rigid spherical HSS ball is pressed across an Aluminum 2024Specimen under definite fluid pressure generated by the hydraulic unit and also shot peening was carried out at a shot velocity of 300 m/s. This research examined the effect of burnishing treatment and shot peening process on beneficial compressive residual stresses.

Dynamic Lifecycle Cost Modeling for Adaptable Design Optimization of Additively Remanufactured Aeroengine Components

Additive manufacturing (AM) is being used increasingly for repair and remanufacturing of aeroengine components. This enables the consideration of a design margin approach to satisfy changing requirements, in which component lifespan can be optimized for different lifecycle scenarios. This paradigm requires lifecycle cost (LCC) modeling; however, the LCC models available in the literature consider mostly the manufacturing of a component, not its repair or remanufacturing. There is thus a need for an LCC model that can consider AM for repair/remanufacturing to quantify corresponding costs and benefits. This paper presents a dynamic LCC model that estimates cumulative costs over the in-service phase and a nested design optimization problem formulation that determines the optimal component lifespan range to minimize overall cost while maximizing performance. The developed methodology is demonstrated by means of an aeroengine turbine rear structure.

Strain hardening exponents and strength coefficients for aeroengine isotropic metallic materials – a reverse engineering approach

The strain hardening exponent and strength coefficient of the Ramberg-Osgood flow rule are required for the accurate design analysis of the materials of aeroengine components. A direct method of deriving these parameters involves the processing of the complete raw data of tensile testing as per ASTM E-646. More often, a first design effort of aeroengine components is made using catalogue data, as the evaluation of material tensile properties is a time-consuming process that takes place concurrently. Catalogue-supplied data on the monotonic loading typically contains elastic modulus, 0.2% proof stress, and ultimate tensile stress along with other data for various temperatures. A methodology was evolved in this work to construct the Ramberg-Osgood flow rule with these three parameters and was validated with laboratory test results and published data through a comparison with ASTM E-646. The strain hardening exponents and strength coefficients were established for a family of aeroengine metallic materials for various temperatures, which can serve as a first design effort input.

Numerical Study on the Adhesion Strength Between Ice and Aluminium Based on a Cohesive Zone Model

Accumulation of ice on aeroengine components could cause serious aircraft accidents. An understanding of the adhesion characteristics of ice-substrate interfaces is essential in order to design reliable anti-icing and de-icing systems. The main purpose of this paper is on the application of a bilinear cohesive zone model to simulate the interface between ice and aluminum by using ANSYS software. A finite element model which coupled with the cohesive zone model is built and some factors that affect the Al/ice tensile strength are discussed. These factors include interface roughness, initial damage of the interface, which is caused by the existence of bubbles. The adhesion strength between ice and aluminum are predicted and analyzed. This model could be used to further study on the mechanisms responsible for the non-linear relationship between the surface roughness and ice adhesion strength.

Kolmogorov Entropy Optimization in the Aeroengine Health Monitoring

Kolmogorov entropy theory was introduced into this paper for time series of one-parameter maximum likelihood estimation of the entropy K, combined with practical applications to aeroengine health monitoring. K entropy value was used to describe the disorder degree of aeroengine parts performance parameters, analyzing the health status and evolutive trend of aeroengine components. Optimization base on K entropy was used to analyze muli-parameter time series trend of K entropy, according to preferred status indicator changes analyzes the overall health of aeroengine. Experimental demonstration on the actual flight data can be more accurately reflected the health of aeroengine,have some significance to fault diagnosis and repair of aeroengine