PSI - Issue 41

Wei Song et al. / Procedia Structural Integrity 41 (2022) 486–491 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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refrigerant necessary for the heat exchange process. As the critical part of the air conditioner, valves allow gas flow from and to the cylinder area based on the pressure difference, while it could block airflow from the opposite direction. It opens when the pressure below the valve exceeds the pressure above, plus the spring force. The valve plate will be subjected to cyclic impact and bending loading during the operation processing of the compressor in air condition. This load-bearing mode will be repeated tens of millions of times with the entire working process [1-3]. In a deterministic valve plate design, mechanical response uncertainty of fatigue properties in design variables is not considered. Therefore, the mechanical fatigue response is essential to realize the reliable design of the valve plate. Sandvik Hiflex martensitic stainless steel, as the valve material of the compressor, is widely used due to its excellent mechanical properties. Its fatigue properties will affect the reliability and performance of the valve in the compressor [4-6]. During the service stage of air condition, the load-bearing mode will accompany the whole work process of the compressor [7]. Once the valve plate fails, it will directly lead to the failure of the compressor and the damage of other parts. However, the mechanical response of the VHCF behaviour of valve plates under different loading conditions is still unclear. It needs more mechanical analysis for guiding the design and service assessment of compressor valve plates. To characterize the fatigue life of compressor valve plates under VHCF, different numerical models were utilized to describe the mechanical conditions under the static and cyclic loadings of compressor valve plates considering the fabrication directions of stainless steel. The VHCF fatigue experimental tests were conducted to compare the fatigue life by different fatigue indicators. The mechanical responses under different loading conditions for the valve plate were further investigated to guide the design and implementation of the compressor.

Nomenclature VHCF Very High Cycle Fatigue

2. Experimental procedure and FE models 2.1. Compressor structure and internal components

According to the service principle of compressor (Fig. 1(a)), the motor drives the gas compression inside the cylinder through the rotation of the crankshaft, and the high-pressure gas is discharged from the flange exhaust port to open the valve plate, and the valve plate is automatically closed after the exhaust is completed in one cycle. The

(a)

(c)

Rivet hole Baffle

Valve plate

Blow vent

Upper flange

(e)

(d)

Blow vent

Valve plate

(f)

Valve plate

Fig. 1. Compressor structures and internal components of air conditions. (a) compressor; (b) Upper flange; (c) components of upper flange; (d) working principle of valve plate; (e) group model of blow vent and valve plate; (f) model of valve plate. Fig. 1. Compressor structures and internal components of air conditions. (a) compressor; (b)