A new stress field intensity model and its application in component high cycle fatigue research.

Songsong Sun,Antonio Riveiro Rodríguez

doi:10.1371/journal.pone.0235323

Abstract

Fatigue limit load is one of the most important and concerned factors in designing and manufacturing critical mechanical parts such as the crankshafts. Usually, this governing parameter is obtained by experiment, which is expensive, time-consuming and only feasible in analyzing the case of simple structure. Still, there's a big obstacle to clear to get the fatigue limit load of a sophisticated structure effectively and efficiently. This paper applied the stress field intensity theory to make quick component fatigue limit load predictions. First, the field diameter of a given crankshaft was determined based on its limit stress state and a stress distribution fitting approach. Then, this parameter was used to predict the high-cycle bending fatigue limit load of a new crankshaft composed of the same material. Finally, a corresponding experimental verification was conducted to evaluate the accuracy of the predictions. The results indicated that the original stress field intensity model may not be suitable due to the errors in the predictions, which can be attributed to the structural features. The new model proposed in this paper can provide higher accuracy in quick fatigue load prediction, making it superior to the traditional model in engineering application.

Highlights

Crankshafts, one of the most important components employed in modern internal combustion engines, are subjected to various dynamic loads during operation
Component high cycle fatigue research based on a new stress field intensity approach
The detailed information of this model is in Table 2: component high cycle fatigue research based on a new stress field intensity approach component high cycle fatigue research based on a new stress field intensity approach

Summary

Introduction

Crankshafts, one of the most important components employed in modern internal combustion engines, are subjected to various dynamic loads during operation. According to the fatigue damage theory [1,2,3], the damage induced by these loads will accumulate until the crankshaft eventually fractures. The serve life of a crankshaft is limited to a certain number of cycles [4]. Compared with the common fatigue property evaluation parameter (usually the fatigue life under a given load) [5,6,7], it is more important to correctly evaluate the high-cycle fatigue limit load of a crankshaft under a specified fatigue life [8,9](which is always determined to be 107 cycles). For structures with complicated shapes, such as crankshafts, standard fatigue testing is time consuming and expensive. Other factors such as the manufacturing process [10,11,12], control strategy [13,14,15], surface strengthening [16,17] will create

Methods

Results

Conclusion