ENGINEERING

Development of an accelerated life test procedure considering the integrated equivalent load of an implement working pump for an agricultural tractor

Seok-Pyo Moon1   Seung-Min Baek2   Sun-Ok Chung1,2   Young-Jun Park3   Tae-Ho Han4,*   Yong-Joo Kim1,2,*   

1Department of Biosystems Machinery Engineering, Chungnam National University, Daejeon 34134, Korea
2Department of Smart Agriculture Systems, Chungnam National University, Daejeon 34134, Korea
3Department of Biosystems &Biomaterials Science and Engineering, Seoul National University, Seoul 08826, Korea
4Agricultural Machinery Certification Team, Foundation of Agriculture. Tech, Commercialization & Transfer, Iksan 54667, Korea

Abstract

The goal of this study was to develop an accelerated life test for an implement working pump for an agricultural tractor. The field experiments were conducted to measure the load of an implement working pump during major agricultural operations such as plow tillage, rotary tillage, baler operations, and wrapping operations. The measurement system for an implement working pump load was constructed using a pressure sensor, the engine rotational speed, and the hitch pump displacement. The measured implement working pump load was calculated as an equivalent load for each agricultural operation using the Palmgren-Miner rule, which is a cumulative damage method. The equivalent load was calculated using the total load data and peak load data when the total data included the operation of an implement working. The annual usage time of the agricultural tractor was applied to develop two integrated equivalent loads. The acceleration factor was calculated to develop an accelerated life test and was calculated from the two integrated equivalent loads, the maximum pressure, and the flow rate conditions of the hitch pump. In Korea, the warranty life of a tractor is 2,736 hours, and the time required for the test to guarantee the operational life of tractors was calculated as 7,561 hours. The acceleration factors were calculated as 453.6 and 38.3, respectively, from the total load data and peak load data. The fatigue test time can be shortened by 16.7 and 197.4 hours according to the result of the acceleration factors.

Figures & Tables

Fig. 1. Palmgren-Miner method for determination of equivalent load using the cumulative-damage rule. (A) Total damage calculation of Palmgren-Miner diagram, (B) calculation of equivalent load using load-cycle diagram. P, hydraulic pressure (bar); L, the number of cycle; K, area of total damage by load; ni, rotations speed at the i load level (rpm); ti, time at the i load level (s).