# Study of Solid Particle Erosion on Helicopter Rotor Blades Surfaces
## 1 Introduction  
Solid particle erosion (SPE) generally refers to erosion and wear on a material surface caused by particle flow or dust at a certain speed and scale. SPE depends on the particle velocity and impact angle, in addition to many other factors [1]. Due to the specialized nature of the work environment, where helicopters and transport aircrafts often take off and land in a desert or on the battlefield, dust erosion is frequently a problem [2]. Erosion caused by high-speed solids can result in component loss, especially in the main rotor blades of helicopters and the turbine blades of aircrafts [3]. The ability to predict the erosion of helicopter rotors blades is extremely important for optimal and safe operation. There have been numerous studies of flow erosion on blades and complex-shaped surfaces. [PERSON] et al. carried out a numerical analysis using Fluent software (Ansys Inc., Canonsburg, PA, USA) of SPE on the blade surfaces of a helicopter main rotor rotating at high rotation speed in a dense, solid particle airflow at low altitude [4]. The authors' results showed that, on the surface, the impact velocity of solid particles increases linearly to the tip of the rotor blade, where the erosion rate distribution is higher. [PERSON] et al. also reported that the circumferential velocity, angle of attack, and blade length were related to SPE on the blade surface of a rotating rotor. Other detailed studies are available in the literature [5; 6; 7; 8; 9]. Early numerical studies on the SPE of rotating blades determined the relevant factors and theoretical equations that affect the SPE of rotating blades, which provided ideas for later researchers, but the content of the study did not consider the material properties of the blades themselves. However, onthe basis of previous researches, this article considers both the impact of particle velocity and other factors on blade erosion, as well as the impact of blade material properties on blade erosion. In numerical studies of solid mechanics, the finite element method (FEM), smooth particle hydrodynamics, and micro-scale dynamic models are commonly applied [10; 11; 12; 13; 14; 15]. [PERSON] et al. used commercial software (Abaqus; ABAQUS Inc., Providence, RI, USA) and FEM to conduct three-dimensional (3D) numerical erosion research; the authors studied the effects of the impact velocity and impact angle of particles with spherical and sharp-edge geometries on erosion, with good consistency seen between numerical and experimental results [16]. The research method of [PERSON] et al. has a great inspiration for this article, but in practice, the shape of the particles is uncontrollable and cannot be used as the main erosion factor. Much of the flow erosion research performed to date has focused on engines, due to the associated fuel costs. As the fan components have a decisive influence on engine thrust and fuel consumption, research on the SPE of the fan blade's leading edge is of great significance. [PERSON] et al. pointed out that the shape of the leading fan blade edge has an important influence on aerodynamic performance in the case of transonic flow [17]. However, [PERSON] et al. did not conduct further research on the effect of blade leading edge shape on erosion. Fewer studies on SPE of helicopter rotor blades have appeared. [PERSON] et al. [18] (1998) conducted early computational fluid dynamics (CFD) studies aimed at predicting erosion. In recent years, new methods such as the discrete element method in solid mechanics, and CFD in fluid mechanics, have been applied increasingly to models of major geometric erosion [19; 20]. [PERSON] et al. performed a numerical erosion analysis with ANSYS Fluent to determine the erosion of solid particles in the pipeline [21]. However, the authors did not discuss and study the erosion protection at the elbow. The resulting erosion equations have since been validated by other experts and scholars [22; 23; 24]. Bionics has been applied in the field of aviation since the 1990s. [PERSON] et al.