scholarly journals PATAHNYA PEGAS ULIR KERETA API AKIBAT KELEBIHAN BEBAN = THE BREAKING OF TRAIN SPRING COIL CAUSED BY OVERWEIGHT

2016 ◽  
Vol 9 (2) ◽  
pp. 59-66
Author(s):  
M. N. Setia Nusa
Keyword(s):  
Fatigue Fracture ◽  
Dynamic Load ◽  
Base Plate ◽  
Hardness Test ◽  
Visual Observation ◽  
Coil Spring ◽  
High Dynamic ◽  
Cantilever Bending ◽  
Recommended Action ◽  
Spring Coil

AbstractAn investigation of a failure coil spring must be applied to the fracture as well the material, to find out the problem. Therefore some recommended action could be given to avoid a repitition of such damage. Some methodes of inspection should be performed such as visual observation, fractography, metallography, hardness test and chemical analysis.The result of investigation showed a fatigue fracture caused by high dynamic load wich is applied during service with a fracture below 5 %. A high cantilever bending tension at each end of the spring has occurred due to overload condition on main base plate wich rised deformation. There by the coil spring has broken. AbstrakPada pegas ulir yang mengalami kerusakan dilakukan pemeriksaan pada permukaan patah dan materialnya, dilakukan penelitian untuk mengetahui penyebab terjadinya kerusakan per koil tersebut dan mencari solusi agar kejadian tidak terulang pada masa yang akan datang. Untuk itu dilakukan pemeriksaan secara visual, fraktografi, metalografi, uji kekerasan dan uji komposisi kimia.Dari hasil pemeriksaan didapatkan temuan kerusakan dengan ciri-ciri patah lelah (fatique) mengalami patah lelah dengan tegangan dinamis yang tinggi dimana area patah lelahnya dibawah 5%. Terjadi tegangan tinggi berupa tegangan bending diujung per karena pelat penumpu mengalami beban berlebih sehingga terjadi deformasi yang memungkinkan terjadinya kondisi kantilever di ujung per tersebut sehingga per tidak kuat menahan beban dan patah. 

scholarly journals Effect of Rail Vehicle–Track Coupled Dynamics on Fatigue Failure of Coil Spring in a Suspension System

2021 ◽  
Vol 11 (6) ◽  
pp. 2650
Author(s):  
Sunil Kumar Sharma ◽  
Rakesh Chandmal Sharma ◽  
Jaesun Lee
Keyword(s):  
Mathematical Model ◽  
Fatigue Fracture ◽  
Suspension System ◽  
Railway Vehicle ◽  
Coil Spring ◽  
Internal Resonances ◽  
Rail Vehicle ◽  
Rail Vehicles ◽  
Stress Result ◽  
Wheel Track

In a rail vehicle, fatigue fracture causes a significant number of failures in the coil spring of the suspension system. In this work, the origin of these failures is examined by studying the rail wheel–track interaction, the modal analysis of the coil springs and the stresses induced during operation. The spring is tested experimentally, and a mathematical model is developed to show its force vs. displacement characteristics. A vertical 10-degree-of-freedom (DOF) mathematical model of a full-scale railway vehicle is developed, showing the motions of the car body, bogies and wheelsets, which are then combined with a track. The springs show internal resonances at nearly 50–60 Hz, where significant stresses are induced in them. From the stress result, the weakest position in the innerspring is identified and a few guidelines are proposed for the reduction of vibration and stress in rail vehicles.

Static Frequency Test and Leaf Fracture Analysis of Turbine Blades in a Power Plant

2019 ◽  
Vol 893 ◽  
pp. 45-51 ◽  
Author(s):  
Bao Tong Chai ◽  
Zheng Feng Wu ◽  
Dong Xing Zhang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Fracture ◽  
Turbine Blades ◽  
Hardness Test ◽  
Surface Damage ◽  
Growth Zone ◽  
Low Pressure ◽  
Composition Analysis ◽  
Blade Vibration ◽  
Blade Root

During the overhaul of a steam turbine of a power station, the frequency of the last twostages of the low-pressure rotor is tested and high-pressure rotor-regulated stage broken blades weresubjected to macroscopic inspection and analysis, chemical composition analysis, hardness test andmetallographic microstructure observation and analysis.The results of blade frequency measurementshow that the two stages of the low-pressure rotor can be safely and stably operated at the workingspeed. The results of broken blade analysis show that: due to the surface damage in the innersurface of the blade root, the blade vibration is aggravated, and the lower step of the concavegroove of the blade root is the stress concentration zone, where the fatigue crack source is generatedand gradually expanded, resulting in fatigue fracture of the blade; The fracture fatigue source zoneand the fatigue crack growth zone occupy approximately two-thirds of the entire fracture area,indicating that the blade fracture is a high-cycle fatigue fracture.

scholarly journals Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load

2006 ◽  
Vol 90 (4) ◽  
pp. 1295-1307 ◽  
Author(s):  
Yasuharu Takagi ◽  
Earl E. Homsher ◽  
Yale E. Goldman ◽  
Henry Shuman
Keyword(s):  
Dynamic Load ◽  
Force Generation ◽  
High Dynamic

scholarly journals ANALISA KEGAGALAN PLATEN TUBE SUPERHEATER PLTU TELUK SIRIH

Power Plant ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 6-18
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Hardness Test ◽  
Visual Observation ◽  
Steam Temperature ◽  
Test Analysis ◽  
Temperature Changes ◽  
Hot Air ◽  
Average Hardness ◽  
Standard Value ◽  
Boiler Drum ◽  
Very High

Superheater is a main part of boiler that serves as one of steam temperature riser after water evaporated by heat inside a boiler. The steam comes out from boiler drum, by utilizing hot air flowinside boiler. Superheater tube is a very important part of process inside the plant, with a high operating temperature of 540°C (in PLTU Teluk Sirih). Because of this, the tube will be maintained by inspection on each scheduled shutdown. Leakages often occur in platen tube of superheater, exactly at its bend or elbow tube. To know causes of the leakages of the part, we conducted observation analysis i.e., visual observation (metallographic testing), spectrometry and hardness test. From the metallographic test analysis, pearlite and ferrite phases present. At the leakage part, it could be observed the tube has lost much of pearlite phase caused by heating. Pearlite micro structure indicates hardness of a material. In spectrometry test of the leaked tube sample using ASTM SA213 T22 standard, value of carbon rises very high by 0.148 from normal value, 0.15 at maximum. We also obtained from it average hardness of 178 HB (ASTM standard). From analysis of the superheater platen tube, damage caused by abrasion of bad materials hit the tube and decreasing pearlite phase caused by temperature changes. Tiny parts of the tube that hit by steam fell eroded and over time the tube broken. Another thing we can conclude is burst of fire in boiler may cause thinning and tube leakage.

scholarly journals FAILURE ANALYSIS ON SLINGER DISK PIPE OF PURIFIED TEREPHTALIC ACID (PTA) VESSEL

2020 ◽  
Vol 14 (2) ◽  
pp. 87-92
Author(s):  
Sukandar Sukandar ◽  
Triwibowo Triwibowo ◽  
Yana Heryana
Keyword(s):  
Chemical Composition ◽  
Failure Analysis ◽  
Fatigue Fracture ◽  
Weld Joint ◽  
Hardness Test ◽  
Hot Water ◽  
Bending Stress ◽  
Shell Wall ◽  
Cause Of Failure ◽  
Load Effects

Slinger disk pipe is a rotary part of PTA vessel with function as anti-fog by swinging hot water to the shell wall to remove solid PTA at the shell wall. Failure took place on this slinger disk pipe. The purpose of failure analysis is to find the root cause of failure. Methods conducted in this failure analysis are examination and testing of fractography, metallography, chemical composition, hardness, and calculation of bending stress. Examination on the fracture surface by fractographic method revealed fatigue fracture with the presence of multiple beachmarks. The position of those multiple beachmarks gave indication of alternation rotation of slinger disk pipe. Examination by metallographic method revealed that initial cracks initiated from heat affected zone of pipe and strengthening plates weld joint. However, result of chemical composition examination and hardness test showed that material of slinger disk pipe were in accordance with lean duplex 2205. Calculation of bending stress gave supporting data of various load effects to slinger disk pipe. Therefore, failure of the slinger disk pipe was caused by fatigue fracture which were initiated from head affected zone of pipe and strengthening plates weld joint.

scholarly journals FATIGUE AND CORROSION PHENOMENON ON FAILURE OF WATER WALL TUBE BOILER

2020 ◽  
Vol 14 (1) ◽  
pp. 29-38
Author(s):  
Eka Febriyanti ◽  
Amin Suhadi ◽  
Laili Novita Sari
Keyword(s):  
Chemical Analysis ◽  
Tensile Test ◽  
Fatigue Fracture ◽  
Material Selection ◽  
Hardness Test ◽  
Root Cause ◽  
Water Wall ◽  
Cause Of Failure ◽  
As Stress ◽  
Water Wall Tube

Water wall tube is one of a boiler components which has a function to transform water to be vapour so that it is normally called steam generating tubes. Any failure on wall tube will affect to the whole boiler system.  The purpose of this research is to find out root cause of failure of wall tube in order to avoid similar case in the future.  Research is conducted by examining and testing the specimens on all aspects including visual, fractography, metallography, chemical analysis, hardness test and tensile test. Examination on the fracture surface by fractographic method found the evidence of fatigue fracture with the presence of beachmark. Another examination on uninstalled boiler tube shows indication of fabrication defect and trans-granular cracks which allowed corrosive agent infiltrated into the microstructure of the tube. However, the result of chemical analysis and tensile test indicated that the tubes investigated are in accordance with ASTM A 210 Grade C specifications. Therefore, the failure of the tube is not caused by wrong material selection, but through the combination of fatigue fracture and corrosion attack where initiated at fabrication defect that acted as stress raisers.

Fenomena Fatik Pada Baut Penyebab Kerusakan Piston Mesin Diesel Suatu Unit Alat Berat Buldozer

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Eka Febriyanti
Keyword(s):  
Diesel Engine ◽  
Tensile Load ◽  
Optical Emission ◽  
Hardness Test ◽  
Visual Observation ◽  
Composition Analysis ◽  
Engine Operation ◽  
Metallographic Examination ◽  
Vibration Fatigue ◽  
Torque Load

Bolt is important component of diesel engine in bulldozer heavy equipment which has function to tight a piston component, so bolt generally experiences tensile load and torque load in its operation. In this research, showed that the bolt failed during diesel engine operation. Therefore, it is necessary to do a detailed analysis of the main causes bolt failure. Observation and examination include visual observation, fracture surface observation by Scanning Electron Microscope (SEM), metallographic examination, hardness test, tensile testing, and chemical composition analysis by optical emission spectroscopy. Detail analysis of the failed bolt was caused by fatigue failure. The failure of bolt was initiated by plastic deformation such as indentation on the outer bolt surface. Incompatibility of clamping and tightening mechanism is allegedly the caused of the indentation on the bolt. The indentation on outer bolt surface acts as stress riser. With the presence of material defect such as MnS inclusion from metallographic examination, vibration, tensile and torque residual stress during operation, fatigue crack formed and propagated until material is no longer able to withstand load that resulted final fracture.Baut merupakan komponen penting suatu mesin diesel pada sebuah unit alat berat buldozer yang salah satunya berfungsi untuk mengencangkan komponen piston. Oleh karena itu, menyebabkan baut tersebut sering mengalami pembebanan tarik dan torsi dalam pengoperasiannya. Pada penelitian ini menunjukkan bahwa baut rusak selama mesin diesel beroperasi. Untuk mengetahui detail penyebab utama kerusakan yang terjadi pada baut perlu dilakukan analisis yang mendalam. Tahapan yang dilakukan antara lain pemeriksaan visual, pengamatan fraktografi dari permukaan patahan baut dengan menggunakan SEM, pengamatan metalografi, pengujian kekerasan, pengujian tarik, dan analisis komposisi kimia material baut. Dari hasil pengamatan dan pengujian menunjukkan bahwa kerusakan baut disebabkan karena pembebanan fatik dimana kerusakan awal ditandai dengan adanya deformasi plastis berupa indentasi/penjejakan di permukaan luar baut. Oleh karena itu, ketidaksesuaian dalam mekanisme pengencangan dan penjepitan piston menyebabkan terjadinya indentasi/penjejakan. Indentasi/penjejakan di permukaan luar baut berperan sebagai peningkat tegangan. Dengan adanya kehadiran cacat material seperti inklusi MnS seperti yang terlihat dari hasil pengamatan metalografi, ditambah dengan getaran, tegangan tarik, dan torsi selama pengoperasian maka retak fatik terbentuk dari indentasi/penjejakan dan merambat sampai material baut tidak dapat menahan beban dan akhirnya patah.Keywords: bolt, inclusion, indentation, vibration, fatigue

Under high dynamic load

2016 ◽  
Vol 13 (2) ◽  
pp. 34-39
Author(s):  
Eduard Kraus ◽  
Ulrich Hack ◽  
Benjamin Baudrit ◽  
Peter Heidemeyer ◽  
Martin Bastian ◽  
...  
Keyword(s):  
Dynamic Load ◽  
High Dynamic

3-Dimensional Microstructure Investigation of High Temperature Corrosion of Boiler Tube Material

2021 ◽  
Vol 889 ◽  
pp. 147-152
Author(s):  
Ariyana Dwiputra Nugraha ◽  
Rasgianti
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Chemical Elements ◽  
Hardness Test ◽  
Local Heat ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Visual Observation ◽  
High Temperature Corrosion ◽  
3 Dimensional

The material of the tubes has suffered localized overheating and corrosion, probably as a result of local heat flux impingement phenomenon, combined with high temperature corrosion. Boiler tubes that experienced failure indications were tubes material SA 213 T22 with the dominant alloy elements is Cr. Materials with these specifications are which should be resistant to corrosion, so it is necessary to carry out laboratory testing to answer suspected indications of failure. The methodology of analysis and identification carried out is by observing the microstructure in 3 dimensions supported by other mechanical tests, namely visual observation, hardness testing, chemical composition testing using SEM and EDAX and testing the chemical composition of the material using a spectrum analyzer. Observation using an optical microscope shows that the microstructure condition of the tube is ferritic and the results of 3D metallography observations show that the tube has undergone micro crack with a measured depth of 1853,28 μm. After the metallography testing is carried out, the hardness test is carried out with the hardness vickers (HV) unit and the minimum hardness is 149 HV and the maximum hardness is 177 HV. Testing of the chemical composition of the deposit showed that there were chemical elements found in seawater that trigger corrosion such as sodium and chlorine which enter the water vapor system. The results showed that the tube had pitting corrosion, which was indicated by the presence of microcrack at the grain boundaries and an oxide deposit had been formed which would cause an overheating phenomenon and deterioration.

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