# Estimation of Impact Loads Transmitted to Vibro-Ripper Housing Using Transfer Path Analysis
## 1 Introduction  
Vibro-rippers attached to excavators are used for various purposes including rock crushing, ground fracturing, structure demolition, and bedrock to produce material or aggregates at construction and mining sites. The size, structure, and major components of a vibro-ripper are illustrated in Figure 1. A vibro-ripper comprises a coupler mounted on an excavator, the isolation rubber to isolate the vibration transmitted to the excavator arm and boom, the directional control valve to control the direction of hydraulic fluid, a pair of eccentric gears in the gearbox, a hydraulic motor that transmits the driving force of the eccentric gear through hydraulic energy during operation, a link module that transmits the excitation force generated by the eccentric gear to the shank and tooth, and a tooth that breaks the rock directly. In operation, a driving force is transmitted to the drive shaft of the gearbox by a hydraulic motor. The drive shaft of the gearbox comprises of a pair of gears and an eccentric weight. The eccentric rotational motion of the drive shaft crushes the rock through the impact of the shank and tooth attached to the gearbox. Previous studies have examined vibro-ripper systems. [PERSON] and [PERSON] [1] undertook failure analysis of an induction-hardened spur gear of a vibro-hammer, and [PERSON] et al. [2] studied the development and application of vibratory driving techniques using a high-frequency hydraulic vibratory hammer. [PERSON] et al. [3] simulated the problem of vibration in an impact ripper working under the excitation force of a hydraulic ripper, and [PERSON] et al. [4] investigated the fatigue life of welded joints on the gearbox shank in a vibro-ripper. [PERSON] et al. [5] studied mechanical vibrations in vibro-hammers. In previous investigations of rock crushing systems, [PERSON] et al. [6; 7; 8] employed a one-dimensional hydraulic simulation and experiments to assess the performance and design method of a hydraulic breaker, while others have focused on improvements to impact performance, minimizing the weight of the breaker housing, and design optimization [9; 10; 11]. Other studies have focused on the development and improvement of vibro-ripper and hammer systems. Impact loads of mechanical devices have also been studied. [PERSON] et al. [12] undertook a quantitative assessment of the impact loads transmitted to the housing of a hydraulic breaker. The authors confirmed the feasibility of the TPA method by comparing the quantified impact loads with the impact energy of the chisel. Other studies have examined the measurement of impact loads, including the use of sensors (e.g., load cells and strain gauges) to assess the impact vibration of a structure, and calculations of structural damage resulting from impact or excitation loads [13; 14; 15; 16; 17; 18; 19]. Previous studies have focused mainly on fatigue life prediction through failure analysis of major parts of vibration rippers; dynamic response analysis of vibration rippers through driving technology, optimal equipment operation, and vibration analysis; and the durability of welded structures. However, there has been no estimation of impact loads transmitted to parts of a vibro-ripper during the crushing of rocks with eccentric rotational motion. Of the key factors that regulate the durability and performance of a vibro-ripper, (e.g., welding structural stability, shank and tooth strength, wear, and the hydraulic system), the stability of parts constituting the structure of the ripper is crucial due to its direct  
Figure 1: Schematic diagram of a vibro-ripper: (**a**) isometric view, (**b**) cross-section A–A\({}^{\prime}\). relationship to machine durability. Impact loads incurred during rock crushing directly affect the structural stability of the crusher and the durability of its components [12; 20].