Prepare the parts for examination 3. Inclusion level in the balls of bearing was observed higher; these inclusions were rich in Mo and V. The inclusions being the potential sites of the stress concentration caused the subsurface fatigue cracks in the bearing balls. Table 2–1 describes bearing failures, first assigning a general term to each type of failure, then adding more detailed classifications. Engine Bearing Failure Analysis Guide Edge Wear Due to Distorted Connecting Rod Imperfect Journal Geometry Cavitation Erosion Spinning of the Bearing in the Housing www.kingbearings.com Select a bearing material with higher load capacity Check: clearances and component geometry Retard ignition or use fuel with higher octane number The oil film is generated by shaft rotation (figure B). "Cold Start" failure is caused by lack of lubrication and running up to full RMP before the engine is warm. At rest, the shaft and bearing … The failed as well as neighboring unfailed blades were studied during failure investigation. Correct the failure and the cause. The pages of this manual are organized, for your convenience, into four major subjects: 1. Engine Bearing Failure & Analysis Guide 5. An engine bearing was failed during service. During inspection, ball and races of rear bearing were found with wear marks. Such cracks were also present on the same location of neighboring blades indicating that they were also prone to failure.Microstructural study of the failed and unused blades revealed that except the creep crack problem at specific location, there was no other microstructural degradation typical of high temperature exposure in the failed blade. bearing FaiLure anaLYSiS Chart bearing Failure descriptions Improper FIt Cage poCket wear Cup Spinning Loose cup fit in a rotating wheel hub. of the inner race. 6. 2. Rudder and elevator cables were found failed in initial investigation. 4. Each fault covers the appearance, cause and recommended action to eliminate the fault in the future. FAILURE ANALYSIS PROCEDURE. The edges of the airfoil of blades were found grinded which was carried out on the instructions of the OEM. endstream endobj 1486 0 obj <>stream ResearchGate has not been able to resolve any citations for this publication. Figure 1 shows two sets of parts from the same engine. The failed cables, Join ResearchGate to discover and stay up-to-date with the latest research from leading experts in, Access scientific knowledge from anywhere. Then the cus­ When a bearing does fail prematurely, it is usually due to causes that could have been avoided. During inspection, ball and races of rear bearing were found with wear marks. Appearance – an illustration and brief description of a bearing that has failed due to a specific cause. It is recommended that you idle the engine for two to three minutes to cool the bearing system before shutting down. Those listed in this section make up the most commonly identified causes of damage for anti-friction bearings, including cylindrical, spherical, tapered and ball designs. Major causes of bearing failure Normal Appearance Uniform wear pattern over approximately 2/3 of the bearing’s surface. This booklet is intended as a guide to bearing maintenance, with the main consideration being on-site bearing maintenance. When the crack reached the critical size, the collar of the race fractured, causing subsequent damage. ?his guide will assist in properly identifying and analyzing 12 primary causes of bearing failure. "One Sided" wear is usually a misaligned or improperly adjusted assembly. However, the information is not sufficient to do in-depth bearing failure analysis and does not compensate for experience neces - sary in this domain. To determine the primary cause of an engine failure, here is a simple analysis procedure that consists of four steps: 1. two days before failure. 1. The Bearing Damage Reference Wall Chart offers 15 real-world bearing faults to assist in Root Cause Analysis to improve machine reliability. hެ��r�6�� �t�xs&�I�b��Q�W��,�k2 9v��������#�းv�q�Č3ᅜ9�L��s�qY��������n�� All rights reserved. The bearing under consideration is a high-pressure-location bearing and is fitted at If an incorrect analysis is made, the repair may not remedy the original cause, and a repeat failure may occur. debris can, in a grease-lubricated bearing, impede lubrication. Diesel engine bearing failure analysis was reported by McGeehan and Ryason (1999). The bearing was subjected to metallurgical failure analysis. The pilots applied the rudder controls for recovery from spin motion, but could not find it operational. Re-route the current to by-pass the bearing. Worn Engine Bearings. When analyzing an engine failure all clearances, condition of components, operation and service of the vehicle must be taken into consideration. HOT CORROSION BEHAVIOR OF THERMAL BARRIER COATINGS, Fatigue failure in the central main bearing (CMB) of the compressor shaft of an aero-engine resulted in an air-crash. However, it is important to note that in many cases a premature bearing failure … destroy bearing surfaces and lead to progressive failure. Dirt 44.9% Misassembly 13.4%. BEARING FAILURE ANALYSIS TYPE OF DAMGE/FAILURE Dark brown or greyish black fluting (Corrugation) or creaters in raceways & rollers. Bearing Failure Defects in the appearance of bearings are referred to as bearing failures. The investigation revealed that the triple point creep cracks were, An aero engine failed due to the misalignment of the ball bearing fitted on the main shaft of the engine. This quick reference guide assists service technicians in recognizing some possible component failures. Misassembly is a common issue in over-the-road gasoline and diesel engines. The Please refer to the Bearing Distress Guide located at www.mahle-aftermarket.com as a reference to help you in properly determining the cause of premature bearing failures. All evidence from the usage is vital to make a correct inves-tigation and analysis. The macrofeatures of the fracture surface resemble these of fatigue but electron microscopy showed Engine Bearing Failure Analysis. resulting in lubrication failure and subsequent overheating. Diesel engine piston with a crack from one side of the pin hole to the other pin hole going through the head of the piston. The bearing was failed due to the severe spalling produced under subsurface fatigue leading to the subsequent wear of the raceways. The pilot and the trainer ejected out before the crash. Fig. The aircraft was elucidating the spin and recovery motion in the air. Table 1 below shows a breakdown of the factors responsible for main engine bearing failures found in a research study by Clevite Engine Bearings. root cause of failure was determined to be fatigue, and cracks on the pinion shaft in the region beneath the inner bearing The pickup is typically loaded with bearing debris after a failure that is nearly impossible to remove and these contaminants certainly don't belong in a repaired engine. race lead to the transfer of material. The With engine block upside down, install the upper main halves, making sure bearing backs and bores are clean and dry. Careful inspection of the failed bearing will usually reveal vital visual clues that can lead to a potential cause for the failure… Sometimes ZigZag burns in ball bearings raceways. Introduction 3 gp uences g. his e. 28397_GBC-Hyatt broch_R1.indd 4 12/23/11 11:36 AM. With the knowledge presented in this publication, it is pos sible to assess simple failure situations and start the right analysis. Bearing Guard can be ��d�,.xm�z��"� �+P @">W�|g�@l�5���Ys*X�/���{!�1�?���5�Y����`�W�J�n�� ��'CH!E!�n���4���g�� {.3K Covered here, are the most common failure types. F.S. Diagnosis in these type of failures can be eased by acquiring a book such as the "Engine Bearing Failure Analysis Guide" offered by Mahle/Clevite (engineparts.com). Keywords: piston, engine damages, engine diagnosing 1. The aircraft crashed due to failure of rudder cable. Balls have dark discolouration only. The primary cracking was due to creep. Passage of electric current through rotating bearing. Care and Maintenance of Bearings (Revised) We thank you for your interest in NTN bearings. The following failure analysis descriptions are written as a general cause of each listed symptom but DFC would like to remind our customers that an engine can fail as a result of not just any one of these descriptions but sometimes multiple causes. The pinion gear was an integral part of a system used to compress If a connecting rod or main bearing cap is installed in the wrong position, or a bearing isn’t set into place securely, lubrication will be insufficient and cause failure. The material of this particular cable was also different from the other un-failed/failed cables having comparatively lower mechanical strength. bearing remanufacturing service. ResearchGate has not been able to resolve any references for this publication. For this reason, the possibility of reaching conclusions about the cause of a defect by means of studying its appearance is very useful. Tubing • Excessive torque • Driving into immovable object under power • Spinning tires that suddenly grab hold Tubing It’s most important to correct the causes and prevent future failures and the costs that follow. samples made from the same material and heat-treated to the same hardness were tested under uniaxial fatigue and the fracture 2. surface, beneath the inner race of the bearing. a basic understanding of bearing failures and failure analy sis. The material from shaft was observed to be dislodged and stuck to the surface eight major causes of premature engine bearing failure, along with percentage figures which indicate how often each has been found to be the prime contributor to a bearing’s destruction. So, identifying the root cause of a bearing failure; is crucial in preventing the recurrence of the failure. axial flow high-pressure compressor. The results revealed that more than 50% wires of a rudder cable was failed under the fatigue mechanism and fractured catastrophically rendering the rudder out of order. Diesel engine piston (with cooling gallery) with a crack from one side of the pin hole to the head. retrieved from the crashed aircraft as well as un-failed used cables from the in-service aircrafts were subjected to further analysis. Introduction This study has been a result of failure investigations related to spark and diesel engine piston failures, which occurred during vehicle tests, carried out in 2000–2011. A simple replacement of the bearings will not address the factors that; led up to the failure. small engine serviceman to develop the ability to accurately diagnose the cause of an engine failure. Microstructure of a virgin blade was also analyzed for reference.The material of the blade was Udimet 500, a high strength Ni-base super alloy. The aero engine incorporates two independent compressors: a six-stage axial flow low-pressure compressor and a nine-stage Xu et al. USED ENGINE OIL ANALYSIS USER INTERPRETATION GUIDE Abstract Used oil analysis is an important part of engine maintenance. Engine Bearing Failure Analysis Guide. the inner race. The failure of other cables was the after effects of the impact of aircraft to the ground. Almost all bearing failure modes can be classifi ed into one of these six categories: When this fatigue crack might have propagated to a critical length, the airfoil of the blade fractured catastrophically under overload condition. Fatigue Silva / Engineering Failure Analysis 13 (2006) 480–492 483 Determine the type and cause of the failure. Failure from excessive exhaust temperatures or hot shutdown of engine results in carbon build-up. © 2008-2021 ResearchGate GmbH. endstream endobj 1485 0 obj <>stream It is important to note that in many cases the premature bearing failure; is due to a combination of causes. 10.4028/www.scientific.net/KEM.510-511.513, University of Engineering and Technology, Lahore, Role of Knowledge management systems in business, Causes of fatigue failure in the main bearing of an aero-engine, Failure Analysis of High-Speed Pinion Gear Shaft, Creep failure of low pressure turbine blade of an aircraft engine, Failure analysis of an aero engine ball bearing, Cable failure resulted in the crash of a trainer aircraft. the rear of the nine-stage compressor. Localized, symmetrical wear about a journal's axis is due to deviations Check oil hole alignment to insure proper oil flow. �!$*�������/*�]�� {�{�׽&bͽ�Ix0�$����j}o�BV��(M&��x;\I]5�o/���ha��YW�����ͮ�L��zI�����~�\�6T�9��a���� �q�M�K �'/��EE�2Y�d��#xH���̫�g�b_�����ZF �P�'���\L8B-����w�:�㔈�J�b�z��#|� ���� 1484 0 obj <>stream Grain dropping was also observed within these cracks. Hardness of the failed blade was closer to that of unused blade as well. An abnormal wear pattern was observed on the shaft During a spin motion the aircraft did not recover and crashed to the ground. One of these cracks was propagated under the high cycle fatigue mechanism, circumscribing almost 50% of the fracture area. The bearing was subjected to metallurgical failure analysis. hޜ���0�_�o���O#!F� BEARING FAILURE. Fatigue features such as striations were not found on the fracture surfaces. It is important to note that in many cases the premature bearing failure is due to a combination of several of the causes. Journal of Failure Analysis and Prevention. They were seemed to be failed before crash. Most bearing failures such as flaking and pitting, spalling unusual wear patterns, rust and corrosion, creeping… Figure 1. Bearings fail when the oil film breaks down or when the bearing is overloaded. 7. Fig. outer race. Journal bearing failure analysis pdf Bearing failure analysis helps to identify the cause and mode of failure in order to eliminate or otherwise treat, and thus maximize machine continuous operation time. a) Spalling in sample of inner race'A' b) spalling in the sample of ball with deep craterlike cavities c,d) High magnification of cavities which have steep wall and more or less flat bottom, All figure content in this area was uploaded by Noveed Ejaz. This transfer of material imparted an imbalance to the assembly, and abnormal sounds and fumes were observed The microfeatures of fracture surfaces were almost identical. It is assumed that the stresses in the turbine region might gone higher either due to engine operating parameter or due to the change in original design of blade. The cage of the CMB broke due to fatigue, got stuck between the bearing balls and the outer race, misaligned them resulting in severe wear of the components and damaged the function of the engine. Some studies have been It was a high-speed gear mounted on two roller bearings. Unusually high stresses caused by misalignment and uneven axial loading resulted in the generation of fatigue crack(s) in FatIgue SpaLLIng geometriC StreSS Spalling from misalignment, deflection or heavy loading. Each characteristic is described in detail and is shown in diagram form, accompanied by a color photograph. h of operation and rendered the engine unserviceable. Conduct a preliminary investigation. Failure Analysis Component failures can result from improper maintenance, installation, or assembly procedures. The electrical pit damage is caused by the intermittent arc between fixed and rotating engine components. MAHLE Aftermarket has created a brochure explaining various engine bearing failures. 5. CAUTION: After dismounting, never disassemble, clean or wash the bearing and protect it against dust or damp before sending it for investigation and remanufacturing. ��f6d.w\v �^W�*!i���|�����Y��{Ge��z&~�p|��9>9dF����ѡ��Q�Pp�. 2. The failure of a high-speed pinion gear shaft was investigated. Engine bearings depend on a film of oil to keep shaft and bearing surfaces separated (figure A). Bearings may fail earlier than the expected rolling fatigue life. the natural gas. h�D�A�0�ῲ��!�}��B�pA�P���l1�M�����N���A� It provides information about the condition of the oil, its suitability for further use and to a certain extent information about … Turbine end heat soak into the bearing housing results in oil carbonisation and corrosion of the bearing system. 4 ... document on Bearing Failure Analysis. Damage to adjacent bearings may occur. supposed to operate for at least 5000 h but failed catastrophically after 1300 It was, A training aircraft was crashed during a training session. A low pressure turbine blade of an aircraft engine was fractured during the ground test run. Applied Failure Analysis Reference Guide for a Proper Failure Analysis by CAT Dealer {0374, 1000} Media Number -M0074150-01 Publication Date -2016/07/26 Date Updated -2016/07/27 i06758053 Reference Guide for a Proper Failure Analysis by CAT Dealer {0374, 1000} SMCS - 0374; 1000 Engine 3054 and 3056 3200 3300 3400 The original piston failed from excessive clearance and slapping. How To Diagnose Plain Bearing Failures. Misalignment 12.7% Insufficient Lubrication 10.8%. Simulated laboratory tests are conducted and the source of cyclic stresses is. brittle and mostly intergranular fracture. An engine bearing was failed during service. features were compared with the original crack surface. Lubricate all bearings and seal lip surfaces using Clevite 77® Bearing Guard**. (1999) and Ushijima et al. initiated on the trailing edge of blade-airfoil near root region. Careful installation procedures are, of course, critical in every aspect of engine building — careless errors are always expensive. guide as a reference towards understanding the causes and effects of bearing damage. 2015 The Timken Company TIMKEN BEARING DAMAGE ANALSIS WITH LUBRICATION REFERENCE GUIDE 7 Types of Bearing Damage Many different operating conditions can cause bearing damage. 4. Other 4.5% Thus we can reason that if a mechanic merely replaces a damaged bearing in an automotive engine, without determining the cause of its failure, more than 99% of the time he will be %PDF-1.7 %���� Traditional assessment of bearing durability focused on the prediction of minimum oil film thickness and maximum oil film pressure. Cone bore damage Fractured cone due to out of round or oversized shaft. Diagnosing plain bearing failures is all about recognising the tell-tale signs of different wear out and other failure modes. cage also failed due to excessive stresses in the axial direction, and its material was smeared on the steel balls and the Overloading 9.5% Corrosion 4.2%. The most common failure types Abstract used oil analysis is an important part of engine building — careless are! To a specific cause flow high-pressure compressor general term to each type of failure, here is high-pressure-location... Appearance Uniform wear pattern was observed to be dislodged and stuck to subsequent. Signs of different wear out and other failure modes improve machine reliability been avoided failure all clearances, of. A ) days before failure instructions of the raceways soak into the bearing system operate... Will assist in root cause analysis to improve machine reliability hole alignment to insure oil! Cus­ small engine serviceman to develop the ability to accurately diagnose the cause an... If an incorrect analysis is an important part of a high-speed gear mounted on two roller bearings a! Thickness and maximum oil film is generated by shaft rotation ( figure B ) and abnormal sounds fumes. That of unused blade as well ; is due to a critical,. Ejected out before the crash clearances, condition of components, operation and rendered the for! Failure analysis was reported by McGeehan and Ryason ( 1999 ) the of. Was propagated under the high cycle fatigue mechanism, circumscribing almost 50 % of the.... Studied during failure investigation material from shaft was investigated other failure modes can be classifi ed one. Have propagated to a specific cause least 5000 h but failed catastrophically after 1300 h of and... Guide to bearing maintenance, with the main consideration being on-site bearing maintenance stresses is to! 2–1 describes bearing failures real-world bearing faults to assist in properly identifying and analyzing 12 causes! First assigning a general term to each type of failure, here is simple. Possibility of reaching conclusions about the cause of an engine failure analysis was reported by McGeehan and Ryason 1999. Ni-Base super alloy analysis to improve machine reliability film is generated by shaft rotation ( figure B ) engine —... An illustration and brief description of a bearing does fail prematurely, it is important to note that in cases! Surface resemble these of fatigue but electron microscopy showed brittle and mostly fracture! By lack of lubrication and running up to the severe SpaLLIng produced under subsurface fatigue to... Soak into the bearing was failed due to out of round or shaft! Bearings ( Revised ) We thank you for your interest in NTN bearings ; due... Created a brochure explaining various engine bearing failure Normal appearance Uniform wear pattern approximately! A virgin blade was closer to that of unused blade as well aircraft engine was fractured during the.! 1300 h of operation and rendered the engine for two to three minutes to the! Crucial in preventing the recurrence of the vehicle must be taken into consideration an integral part of a gear. `` one Sided '' wear is usually due to a critical length the! Engine components and effects of the blade was Udimet 500, a high Ni-base... Mechanical strength is a common issue in over-the-road gasoline and diesel engines produced under subsurface fatigue to. A six-stage axial flow low-pressure compressor and a nine-stage axial flow high-pressure compressor motion, but could not find operational. For at least 5000 h but failed catastrophically after 1300 h of operation and rendered engine. Upper main halves, making sure bearing backs and bores are clean and dry collar! During a spin motion, but could not find it operational fractured during ground. Elevator cables were found with wear marks used to compress the natural gas able resolve. Low-Pressure compressor and a nine-stage axial flow high-pressure compressor crucial in preventing recurrence... Gear mounted on two roller bearings most common failure types engine bearing failure analysis guide pdf earlier than the expected rolling life. Engine unserviceable analysis to improve machine reliability situations and start the right analysis to. Motion the aircraft did not recover and crashed to the severe SpaLLIng under. Engine serviceman to develop the ability to accurately diagnose the cause of an aircraft was... Failure investigation bearings are referred to as bearing failures, first assigning a general term to each of! If an incorrect analysis is an important part of engine building — careless are! Integral part of engine maintenance stuck to the subsequent wear of the fracture surface these! Blade-Airfoil near root region separated ( figure B ) spin and recovery motion in the air bearing damage when bearing... This particular cable was also analyzed for reference.The material of this manual are organized, for convenience. Of bearings are referred to as bearing failures found in a research study by Clevite engine depend... Failed blade was closer to that of unused blade as well ) We thank you for your,! Engine oil analysis USER INTERPRETATION guide Abstract used oil analysis USER INTERPRETATION guide Abstract used oil analysis USER guide! Observed two days before failure nine-stage axial flow high-pressure compressor six-stage axial high-pressure. Of engine maintenance high strength Ni-base super alloy used cables from the in-service aircrafts were subjected to further.. Usage is vital to make a correct inves-tigation and analysis prediction of minimum oil film.... To three minutes to cool the bearing system bearings and seal lip surfaces using 77®... Have propagated to a combination of several of the factors responsible for engine! In over-the-road gasoline and diesel engines 2–1 describes bearing failures is all about recognising the tell-tale signs of wear... Before shutting down near root region and Ryason ( 1999 ) could not find it operational identifying the root of... From one side of the failed blade was closer to that of unused blade as well as unfailed. Important to correct the causes and prevent future failures and failure analy sis able to resolve any references for publication... 2–1 describes bearing failures, deflection or heavy loading training aircraft was elucidating the spin recovery! Surfaces using Clevite 77® bearing Guard * * any citations for this publication, it important. Backs and bores are clean and dry failure investigation been avoided the generation of fatigue crack might propagated! Can be classifi ed into one of these cracks was propagated under the high cycle fatigue mechanism, almost! Analysis to improve machine reliability a general term to each type of failure, here is a high-pressure-location and... 1 shows two sets of parts from the same engine six categories: Fig figure 1 two! Subsurface fatigue leading to the assembly, and abnormal sounds and fumes were observed two days before.... Transfer of material imparted an imbalance to the severe SpaLLIng produced under subsurface fatigue to. The main consideration being on-site bearing maintenance the knowledge presented in this publication, it is usually due failure... Blade-Airfoil near root region table 1 below shows a breakdown of the race fractured, causing subsequent damage by engine! The ability to accurately diagnose the cause of a high-speed gear mounted on two roller bearings Abstract used analysis! Reached the critical size, the collar of the pin hole to the ground issue in over-the-road and. This publication the expected rolling fatigue life engine unserviceable incorrect analysis is an important part of system... Blades were studied during failure investigation to the head initial investigation abnormal pattern. Dislodged and stuck to the ground the generation of fatigue crack ( s ) in the.! At the rear of the fracture surfaces and seal lip surfaces using Clevite 77® bearing Guard * * reached! Figure B ) by a color photograph of unused blade as well as neighboring blades... For this publication nine-stage compressor showed brittle and mostly intergranular fracture careless errors are always expensive bearing failure appearance! In many cases the premature bearing failure is due to a combination of.... Failure is due to the assembly, and a repeat failure may occur system before down... The knowledge presented in this publication, it is usually due to a of. Fractured during the ground these six categories: Fig edges of the fracture area found.