IJERT-Finite Element Analysis of a Diesel Generator Cylinder (original) (raw)

Analysis of a diesel generator cylinder failure

Engineering Failure Analysis, 2010

This paper analyses a catastrophic cylinder failure of a four stroke 14 V diesel engine of an electrical power plant when running to nominal speed of 600 rpm. The rated power of the engine was 7.5 MW and before failure had accumulated 80,000 h in service operating mainly at full load. As a result, the piston and liner of cylinder 4 were broken; the crankcase and main crankshaft bearings next to this cylinder were also damaged. The mechanical properties of the liner (grey cast iron) and piston body (aluminium alloy) including tensile properties and Brinell hardness were evaluated. No signs of fatigue failure were identified in liner and piston. A finite element model of the liner has shown that the most heavily loaded areas match the fractured zones.

Failure analysis of a diesel engine cylinder head based on finite element method

Engineering Failure Analysis, 2013

Macro fatigue cracks are expected to occur in valve bridges of cylinder head when engine is operating in normal working condition. In order to determine the causes of these failures, stress analysis is carried out using finite element method with a concern of temperature dependency of material properties. Mechanical and thermal properties of material tested at high temperatures are applied to the finite element analysis. Furthermore, temperatures of the cylinder head in actual working condition are measured to validate the simulation results of finite element analysis. After that, stress computation is performed and the regions of stress concentration on the flame deck surface are obtained. The analysis results of stress show that the regions of stress concentration are in agreement with the actual failure regions of the cylinder head. When analyzing the failures on the flame deck surface of a cylinder head by evaluating stress concentration, temperature's effect on mechanical strength of material should not be ignored. The methodology of failure analysis proposed in this paper is time-saving and also relatively accurate and predictive in actual engineering practice.

Failure analysis of a cylinder sleeve from a turbocharged diesel engine

Engineering Failure Analysis, 2009

This work presents the conclusions of a failure analysis performed on a V12 Turbo Charged diesel engine cylinder sleeve. The failure analysis carried out established the most relevant factors that caused damage to the cylinder sleeve. An examination of the internal surface of the cylinder sleeve revealed an elevated number of cavities close to the top center area, which acted as stress concentrators reducing the resistance of the component, creating crack nucleation spots. Additionally there were internal differences in the microstructure of the component, which indicate that different cooling conditions occurred during its manufacture, providing a secondary failure mechanism, due to material fragility.

Failure analysis of a damaged diesel motor crankshaft

Engineering Failure Analysis, 2019

A case study of a catastrophic failure of a diesel motor crankshaft is presented. The aim of this failure analysis is to investigate the root cause of this important mechanical component. This crankshaft belonged to a particular vehicle (140 cv, at 4000 rpm, 1968 cm3 displacement) that fractured after 180,000 km and 8 years in service. The motor was disassembled, and the crankpin No. 3 and the main bearing cap No. 4 were broken. Defects of material and machining defects were not found at the crack initiation sites by optical and SEM microscope. Results shown that the crankpin and the main bearing cap clearly failed by fatigue, and the root cause seems to be related with deficient tightening of the main bearing cap No. 4, which fractured due to a crack developed on the its outer side. The main journal No. 4 did run out of support, and the crankthrow No. 3 increased the alternating stress amplitude, whereby an inevitable catastrophic crankshaft failure happened.

Failure analysis of four-cylinder diesel engine crankshaft

Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2018

In this article, failure analysis was examined in four-cylinder light-duty truck diesel engine crankshaft. The failure happened in service after 95,000 km of operation by fatigue crack growth which was initiated from a surface defect on the second crankpin from the crankpin-web fillet. For such objective, standard specimens were cut off from the crankshaft and examined to evaluate the mechanical properties. Some hardness and tensile tests were conducted, and spectrometry analysis was used in order to study the chemical composition of the crankshaft material. Also, for considering and evaluating the microstructure, microcracks, fracture surface and the cause of failure, optical microscopy and scanning electron microscopy equipped with energy-dispersive spectrometry were used. The morphology of the fracture surface shows that the failure happened in the second crankpin at the crankpin-web fillet of crankshaft where the stress concentration was the highest.

Analysis of fatigue cracks of cylinder heads in diesel engines

Journal of Theoretical and Applied Mechanics, 2016

Loading conditions and complex geometry have led cylinder heads to become the most challenging parts of diesel engines. One of the most important durability problems in diesel engines is due to cracks in the valves bridge area. The purpose of this study is thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoplasticity model. The results of the thermo-mechanical analysis indicate that the maximum temperature and stress occurr in the valves bridge. The results of the finite element analysis correspond with the experimental tests carried out by researchers, and illustrate cracks in cylinder heads in this region. The results of the thermo-mechanical analysis show that when the engine is running, the stress in the region is compressive, caused by thermal loading and combustion pressure. When the engine is shut off, the compressive stress turns into tensile stress because of assembly loads. The valves bridge is under cyclic tensile and compressive stress state and thus is subject to low cycle fatigue. After several cycles fatigue cracks will appear in this region. The lifetime of this part can be determined through finite element analysis instead of experimental tests. The viscous strain is greater than the plastic strain which is not negligible.

Failure mode analysis of two crankshafts of a single cylinder diesel engine

Engineering Failure Analysis, 2015

This paper reports an investigation carried out on two damaged crankshafts of single cylinder diesel engines used in agricultural services for several purposes. Recurrent damages of these crankshafts type have happened after approximately 100 hours in service. The root cause never was imputed to the manufacturer. The fatigue design and an accurate prediction of fatigue life are of primordial importance to insure the safety of these components and its reliability. This study firstly presents a short review on fatigue power shafts for supporting the failure mode analysis, which can lead to determine the root cause of failure. The material of these damaged crankshafts has the same chemical composition to others found where the same type of fracture occurred at least ten years ago. A finite element analysis was also carried out in order to find the critical zones where high stress concentrations are present. Results showed a clear failure by fatigue under low stress and high cyclic fatigue on crankpins.

A study upon medium displacement Diesel Engine failure

2018

The study aims to determine the failure cause of an internal combustion engine, in a particular case for a medium displacement diesel engine. The general issue of internal combustion engines failure is very complex and comprehensive. The assumed analysis for achieving this objective is complex and involves a multidisciplinary and gradually approach of the problem, as well as the development of an appropriate methodology to ensure the accuracy of the outcome. In principle, the cause of the engine breakdown is related to its mobile equipment. Based on this assumption, the authors identified all the affected moving parts organs and defined the damage they recorded. Neither fixed collaterally affected parts have been neglected, due to the organic interaction between the mobile equipment and the fixed parts of the engine. The present paper is a real "good practice support" in approaching the causes of fatal destruction of engines, the theoretical considerations being accompanie...

The Analysis of Light-duty Truck Diesel Engine Crankshaft Failure

2018

In this study, crankshaft failure of four-cylinder light-duty truck diesel engine was examined. The failure occurred by fatigue crack growth which was initiated from a surface defect after about 95000 km on the second crankpin from the crankpin-web fillet where the stress concentration was at the highest level. To evaluate the mechanical properties, some hardness and tensile tests were conducted and spectrometry analysis was used for studying the chemical composition of the crankshaft material. Additionally, for considering and evaluating the microstructure, microcracks, fracture surface, and the cause of failure, optical microscopy (OM) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS) were used. The morphology of the fracture surface showed a smooth and flat crack initiation with the beach marks and ratchet marks and second crack propagation zone with beach marks and fast final fracture zone near the end. The results of EDS observations indi...