*Article* **The Random Vibrations of the Active Body of the Cultivators**

**Petru Cardei 1, Nicolae Constantin 2, Vergil Muraru 1,\*, Catalin Persu 1, Raluca Sfiru 1, Nicolae-Valentin Vladut 1, Nicoleta Ungureanu 2,\*, Mihai Matache 1, Cornelia Muraru-Ionel 1, Oana-Diana Cristea <sup>1</sup> and Evelin-Anda Laza <sup>1</sup>**


**Abstract:** The article continues the exposition of the results obtained in researching an agricultural machine for processing soil, designed for research with applications including exploitation. The MCLS (*complex machine for soil tillage*) was designed to research the working processes of the instruments intended for soil processing. The MCLS cultivator is a modulated machine (it can work for three working widths: 1, 2, and 4 m, with tractors of different powers) that is designed to use a wide range of working bodies. The experimental data obtained with the structure with a working width of 1 m and the results of their processing within the framework of the theory of random vibrations are presented in this article. The experimental results are analysed as random vibrations of the supports of the active working bodies. As a result, the main characteristics of random vibrations are exposed: the distribution function, the average value, the autocorrelation, and the frequency spectrum. These general results regarding random vibrations are used for several critical applications in the design, execution, and exploitation of some subassemblies and assemblies of agricultural machines of this type. The main applications include estimating the probability of the occurrence of dangerous load peaks, counting and selecting the load peaks that produce fatigue accumulation in the material of the supports of the working bodies, identifying some design deficiencies or defects in the work regime, and estimating the effects of vibrations on the quality of soil processing. All of the outcomes are composed of applications in MCLS research and exploitation. The applications pursue well-known objectives of modelling the working processes of agricultural machines: safety at work, increasing the quality of work, optimising energy consumption, and increasing productivity, all in a broad context to obtain a compromise situation. The material and the method are based on experimental data acquisition, processing, and interpretation.

**Keywords:** random; vibrations; tillage; tools; complex; cultivator
