Research Article Estimation of Impact Loads in a Hydraulic Breaker by Transfer Path Analysis Changheon Song, 1,2 Dae Ji Kim, 2 Jintai Chung, 1 Kang Won Lee, 2 Sang Seuk Kweon, 2 and Young Ky Kang 3 1 Department of Mechanical Engineering, Hanyang University, 1271 Sa-1-Dong, Ansan, Kyunggi-Do, Republic of Korea 2 Construction Equipment R&D Center, Korea Institute of Industrial Technology, Gyeongsan-si, Republic of Korea 3 R&D Center Breaker Development Team, Soosan Heavy Industries Co., Ltd, Hwaseong-si, Republic of Korea Correspondence should be addressed to Sang Seuk Kweon; sskweon@kitech.re.kr Received 13 June 2017; Accepted 27 August 2017; Published 22 November 2017 Academic Editor: Filippo Ubertini Copyright © 2017 Changheon Song et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te aim of this study is to estimate the impact loads delivered to the housing of a hydraulic breaker quantitatively. Striking forces caused vibrations in the equipment housing, which were experimentally measured, and frequency response functions were also found through modal impact experiments. Transfer path analysis (TPA) method of the data quantifed the impact loads delivered to the housing. TPA method can analyze the relationship between the vibration energy and the transfer path of an excitation source and so explore the way in which vibrations on each path contribute to the entire vibration profle. Te impact loads of each part derived by TPA method were compared with the impact loads in the chisel derived from strain gauge measurements of the striking energy. Tis comparison validated the TPA approach. Tis study describes the basic concepts and components of TPA method and also reviews its applicability to mechanical equipment that experiences impact vibrations and impact loads. 1. Introduction Hydraulic breakers have various uses. For example, excava- tors ofen use them to fracture the ground or bedrock to produce materials or aggregates or to demolish structures (Figure 1(a)) [1, 2]. A hydraulic breaker comprises a direc- tional valve to control the direction of fuid fow, an accumu- lator to store the hydraulic energy and to supply the required fow during operation, a back head flled with nitrogen gas, pistons for delivering the striking energy to the chisel while performing a reciprocal motion, and a chisel that breaks the subject material directly. Te hydraulic breaker is mounted on an excavator by a coupler (Figure 1(b)). Te hydraulic breaker is a typical attachment commonly found at industrial and construction sites. As modern industrial technology devel- ops, consumers demand higher standards. Terefore, indus- trial and construction equipment now requires high struc- tural stability as well as intelligence, performance, and ef- ciency. Recent studies of hydraulic breakers include the work of Ficarella et al. [3–5], who used a 1D simulation and experimental tests to investigate the performance and design of a hydraulic breaker. Several other studies have focused on improving performance, reducing the weight of the housing, and optimizing vibration and noise [6–8]. However, few studies have sought to quantify the impact loads delivered to the housing, even though these loads are closely related to the durability of the equipment. Among the numerous factors that determine the performance of a hydraulic breaker (the hydraulic circuit and the design of the striking piston, shuttle valve, etc.), the structural stability of the housing is directly related to the durability and lifespan of the equipment, making it one of the most important design factors. Hence, to predict the lifespan of the equipment and the durability of the housing efectively, the impact loads delivered to the housing during striking should be analyzed. Such analysis is impor- tant, because a hydraulic breaker ofen experiences extreme conditions in its various applications that see it constantly enduring impact vibrations and impact loads. Tere are many methods for measuring static and impact loads such as using force sensors or strain gauges. Static Hindawi Shock and Vibration Volume 2017, Article ID 8564381, 15 pages https://doi.org/10.1155/2017/8564381