Crank Pin Research Articles

Optimized design of silicone oil torsional damper for diesel generator

Abstract Due to the high cylinder pressure and high-performance requirements, the silicone oil damper of an inline six-cylinder diesel generator needs to be optimized to reduce the crankshaft stress. The centralized mass method was used to simplify the crankshaft system. A multi-body dynamic model was established, and the crankshaft stress and torsional vibration amplitude were simulated. The results show that the excessive shear stress at generator crank pin 5 is due to the resonance between the first-order intrinsic frequency of the shaft system and the 3rd harmonic torsional vibration. The shear stress was analyzed for different damper thicknesses and stiffnesses, and it was found that the shear stress at crank pin 5 was minimized when the damper thickness was 60 mm and the torsional stiffness was 250,000 N·m/rad. The torsional amplitudes at different speeds and frequencies were measured in the bench test, and the results were consistent with the calculations. The designed silicone oil torsional damper meets the requirements of the 2000-hour bench test.

COMSOL-based fatigue simulation of crankshaft

The crankshaft is the most valuable and precise single component of the automobile engine, and the force of the crankshaft is extremely complex. It works under the combined action of periodic changes of gas pressure, reciprocating inertia force, and torque, and bears huge bending and torsional alternating loads. It is of great significance to study the effects of bending, torsional, and compound loads on the strength and fatigue life of crankshaft. In this paper, a crankshaft simulation model is established according to the fatigue reliability theory, the fatigue reliability of the crankshaft is determined, the fatigue life is analyzed, the stress-strain simulation of the crankshaft is carried out by COMSOL, and the fatigue load spectrum and damage cloud map of the crankshaft are obtained. The results show that the structural parameter that has the greatest influence on the stress and deformation of the transition rounded radius. The position corresponds to the place of the crank pin where maximum stress occurs.

Modeling and simulating axial vibrations on the crarkshaft of the large two-stroke marine diesel engine

The axial vibration is the strong vibrated phenomenon occurring on the main propulsion using a large two-stroke marine diesel engine. This article researches to build a mathematical model of the axial stiffness coefficient and force generated by the geometric configuration of the crank pin-crank web assemblies and the combustion gas force. The numerical simulation is performed by finite element method, using ANSYS software, applied to the main engine MAN B&W 6G70ME. Keywords: Axial stiffness; crank pin–crank web set; axial force; diesel crankshaft; large two-stroke marine diesel engine; Axial vibration simulation.

Analysis of rigid-flexible coupled torsional vibration and vibration suppression of crankshaft system under multiple working conditions

With the rapid development of shale gas resources in China, there is an increasing demand for large and multiple column compressors. However, this development has brought to light the issue of torsional vibration in compressor crankshaft systems, particularly under variable loads and multiple working conditions. In order to reduce the torsional vibration of the compressor crankshaft and ensure the safe and stable operation of the compressor unit, this study proposes a method for calculating and suppressing torsional vibration in the crankshaft system of a shale gas compressor, which takes into account the flexibility effect of various parts and considers multiple working conditions. The analysis focused on the rigid-flexible coupling torsional vibration characteristics of the crankshaft system under multiple working conditions, considering the flexible deformation of the main bearing, connecting rod, and crankshaft. The study successfully determined the torsional vibration response of the crankshaft system under seven typical working conditions. Furthermore, for the worst conditions, a detailed analysis of the vibration response of the crankshaft system was conducted and carried out a study on suppressing crankshaft torsional vibration through response surface optimization design. The study findings indicate that the compressor system exhibits low-frequency vibrations during operation. The maximum torsional angular deformation at the crank pin of the fourth column is measured to be 0.052°. Following structural optimization, the relative torsional angular deformation of the crank pin is reduced by 25.61% under the worst operating conditions. Moreover, the peak angular velocity of the center of mass is reduced by 22.17%. These results demonstrate a significant suppression effect on torsional vibrations in the compressor crankshaft system, leading to improved working safety.

Cylinder Liner Velocity Calculation under Dynamic Condition in the Pursuit of Liner Cavitation Investigation of an Internal Combustion Engine

<div>An analytical method for nonlinear three-dimensional (3D) multi-body flexible dynamic time-domain analysis for a single-cylinder internal combustion (IC) engine consisting of piston, connecting rod, crank pin, and liner is developed. This piston is modeled as a 3D piston that collides with the liner as in a real engine. The goal is to investigate the piston slap force and subsequent liner vibration. Liner vibrational velocity is directly responsible for pressure fluctuations in the coolant region resulting in bubble formation and subsequent collapse. If the bubble collapse is closer to the liner surface, cavitation erosion in the liner might occur. The mechanism of liner cavitation is briefly explained, which would take a full computational fluid dynamics (CFD) model to develop, which is out of scope for the present work. However, as a first step, the present method focused on a comprehensive and accurate estimation of the highest inward and outward liner velocities, which are directly related to the bubble formation and collapse, respectively. Sensitivity of liner velocity to different engine-operating conditions (warm and hot, with highest skirt temperatures of 178 and 130°C), piston pin bore offsets (thrust side, anti-thrust side directions in the amounts of 0.6 mm, and the nominal no offset case), and liner thicknesses are determined. Piston thermal growth is considered as part of the analysis resulting in interference condition between piston skirt and liner under the hot operating condition and low minimum clearance under the warm condition. Correlation of liner velocity contour plots with real engine liner cavitation erosion is presented. Analytical model showed a maximum liner inward velocity of 55 mm/s with no piston pin offset under nominal engine-operating configuration. A correlation has been found between location of this highest liner velocity and location of the actual cavitation erosion in the field.</div>

Failure Analysis of a Diesel Engine Crankshaft based on Finite Element Modeling

The crankshaft is one of the essential components of an internal combustion engine that converts the piston's linear motion into the crank's rotary motion. This research has been carried out to study the failure analysis of diesel engine crankshafts, and forged steel material is selected. A crankshaft's geometry is relatively complex compared to other parts; its working conditions are critical, and the stress concentration areas are very complicated. While considering all these phenomena, it is significant that a crankshaft's fatigue strength, stiffness, durability, and wear resistance should be checked and analyzed properly. Firstly, a 3D model of the crankshaft is designed using SolidWorks 2022 software. After that, the Model is imported to ANSYS software 2022 R2 student version. However, using ANSYS (finite element method) is carried out on the crankshaft’s Model. This research aims to obtain the variation in stress magnitude at critical locations of the crankshaft by applying variable loads and boundary conditions. Simulation techniques were conducted for both static and dynamic analysis. The total deformation observed at the critical area of the crank pin is 1.3488e-8. The corresponding equivalent stress is 318.37, and the crankshaft's safety factor is 15.

2700kW主機関クランク軸に発見された溝状欠陥の疲労強度評価

A grooved defect of 0.43mm depth x 7mm width x 370mm length = 1/3 circle caused on crank shaft of 2700kW main diesel engine was found during CMS inspection of special survey dock. At first permanent repair by machining the crank pin to remove 1.0mm depth all around with fitting oversized crank pin metal have been discussed. However it is expected for 3 months at least to make up oversize crank pin metal. So, the vessel was sailed out after removing notches from the defect carefully with confirming safety condition by stress calculation with fatigue strength evaluation of the crank shaft contained the defect and checking lubricating flow condition. This time, its summary is shown in this paper.

Investigations on multi cylinder four stroke diesel engine’s crankshafts with different materials

A crankshaft consists of several cranks and crank pins connected in series with the connecting rod to an engine which works on crank mechanism. Moreover, crankshaft is a mechanical part which converts reciprocating motion to rotational motion and vice - versa. In this project, an attempt is made to study the static behaviour fatigue life, damage and factor of safety was determined using structural analysis. A three-dimensional model of the multi cylinder four stroke diesel engine crankshafts was created. Various materials like Mg alloy AZ31, EN8 BS970 (008M40), Cu-Be alloy C17200, Titanium alloy Ti6Al4V, Al alloy 7068 were chosen for this study based on the working conditions and mechanical properties of forged steel to enhance the properties of the crankshaft. To determine the variation of stress magnitude at critical locations, the finite element analysis is done on the crankshaft. The crankshaft analysis was performed with suitable load and boundary conditions, with the static analysis, Von-mises stress induced in the crankshaft is compared with different chosen materials and deformations were also discussed. The results obtained from analysis will give a theoretical foundation for improvement and optimization of crankshaft, which reveals that titanium alloy (Ti6Al4V) has shown better strength and low deformation than the cast iron.

Strength Analysis and Structure Optimization of the Crankshaft of an Opposed-Power Reciprocating Pump

The opposed-power reciprocating pump has the characteristics of high pressure, large flow, and high efficiency and energy saving. However, due to the special structure of the opposed-power reciprocating pump, existing theoretical methods cannot analyze its dynamic performance. Therefore, this paper proposes a method of analyzing the power end of the opposed-power reciprocating pump. Firstly, according to the working principle and structural characteristics of the traditional plunger pump, the novel and complex structure of the opposed-power reciprocating pump is analyzed by analogy, and the force analysis model of the crankshaft is established. The dynamic analysis model of the Matlab program is used to solve the dynamic load and section stress in the working process, and the variation law of crankshaft load is obtained. The 25 most critical working conditions are selected for analysis, and the most critical station and section of the crankshaft are obtained. With the connection between ANSYS Workbench and Solidworks, the model is imported into ANSYS Workbench, the load on the crank pin is loaded by APDL command flow, and the static analysis of the crankshaft is carried out to obtain the stress and strain of the crankshaft. Finally, the static and fatigue strength of the dangerous section is checked, and it is proven that the strength and stiffness of the crankshaft meet the design requirements. The results show that the dynamic analysis results of the crankshaft under critical working conditions are consistent with the finite element analysis, verifying the rationality of the method and providing a reference for the improvement and optimized design of the crankshaft of the opposed-power reciprocating pump.

Finite Element Analysis of Connecting Rod using Composite Material

Abstract: The connecting rod is the intermediate member between the piston and the Crankshaft. Its primary function is to transmit the push and pull from the piston pin to the crank pin, thus converting the reciprocating motion of the piston into rotary motion of the crank. This thesis describes designing and Analysis of connecting rod using composite materials. In this, drawing is drafted from the calculations. In this project connecting rod is replaced by aluminum based composite material reinforced with Boron carbide. And it also describes the modeling and analysis of connecting rod. NX solid modeling software is used to generate the 3-D solid model of Connecting rod. ANSYS software is used to analyze the connecting rod. The main aim of the project is to analysis the stress, strain, deformation of connecting rod by varying material with same geometry. Keywords: Connecting Rod, Analysis of Connecting Rod, Aluminum Alloy Connecting Rod, Design and Analysis of Connecting Rod.

A study on triply periodic minimal surfaces: A case study

Connecting rod is mounted between piston and crankshaft. It converts reciprocating motion of piston into rotary motion of crankshaft and this conversion is inform through the pull and the push from piston pin and crank pin. A shank connects the big and the small end of the connecting rod. The current study involves in exploring the use of minimal surfaces concept to eliminate the solid shank without compromising in the strength that the I-section provides to the connecting rod. In this designing process, a triply periodic minimal surface has been introduced into cavity located at shank. Moreover, a parametric model of connecting rod is modelled through a solid modeling software and later taken to another modeling software where the minimal surface is being modeled. The model is then analyzed for its structural stability by an analysis software. Von-misses stress and total deformation have been estimated and compared with that of the traditional design. It has been observed that through the implementation of minimal surface there has been an appreciable reduction in overall stress and the total deformation.

Development of special purpose silk thread through reverse engineering and yarn geometry for use in engines of battle tanks

One of the Engine factories in India is manufacturing three types of engines that power various types of battle tanks. While operating the tanks, the crank shaft main journals and pins need lubrication for smooth running with minimum friction and to dissipate the heat produced. In order to prevent the leakage in the lubricating system, special purpose silk thread is wound around the threaded portion of the bolt before tightening the nut with gasket and washer that has to withstand the oil pressure of 14 kg/cm2 at a temperature of 140 °C. The expected life of the engine is 10 years approx. (500 h of actual running), so the special purpose silk thread should have self-life of more than the engine life. Earlier, the special purpose silk thread of 77.2 Tex (maximum) that would have a breaking load of 2 kgf (minimum) with 18% elongation at rupture (minimum) was sourced from Japan indirectly. Due to decline in the silk production in Japan, the supply chain broke and ceased to exist. The technical know-how on yarn manufacturing was unknown but details of eight thread characteristics were available. CSTRI, Bangalore, with the data, manufactured the special purpose silk thread through reverse engineering by designing the yarn geometry using indigenously produced multivoltine raw silk reeled on multiend reeling machine. Subsequently, the special purpose thread was produced in commercial scale and supplied to the Engine factory, Avadi that is being used as oil seal in the engines of battle tanks after getting the performance test report from the Defence quality control agency. This research paper deals with process of reverse engineering and design of yarn geometry in achieving the desired characteristics of the special purpose silk thread.

Fabrication and finite element analysis of two wheeler connecting rod using reinforced aluminum matrix composites Al7068 and Si3N4

Abstract A connecting rod is an intermediate link between the Piston and the Crankshaft. The primary function of the connecting rod is to transmit the motion from the piston pin to the crank pin, thus converting reciprocating motion of a piston into the rotary motion of crank. Connecting rod plays an important role while designing the Diesel or Petrol Engine. The changes in the material (Al7068 alloy and Si3N4) of the connecting rod to increase its strength to weight ratio while maintaining or reducing the maximum stress, maximum strain and the maximum deformation developed during loading. The performance of the component can be analyze by using the ANSYS software and the properties of the material can be find out by performing different tests, after manufacturing the composite material by using an appropriate fabrication process, connecting rod has been modeled in CREO according to specific engine specifications of TVS Apache 150 model. Stress, Strain and the deformation analysis of the connecting rod is carried on the ANSYS WORKBENCH.

Finite element analysis of a vehicle diesel engine crankshaft

The crankshaft is the largest moving part in the engine and one of the most important parts in the engine. It bears the force transmitted from the connecting rod and converts this force into torque. The working conditions of the crankshaft are harsh, and its stress conditions are quite complicated. The stress concentration phenomenon is quite serious under the effect of bending and torsion loads, especially in the rounded transition area from the crank to the journal. In addition, the crankshaft has a significant impact on the overall size, weight, reliability, and manufacturing cost of the engine Therefore, the fatigue strength, stiffness, and wear resistance of the journal must be strictly checked and analyzed during the design of the crankshaft. In this paper, the finite element method is used as the main research method to analyze the static strength of a diesel engine crankshaft. The pre-processing software is used to optimize the topology of the crankshaft 1/2 single turn and the tetrahedral meshing. Then the finite element analysis software is imported to set the boundary Condition and apply the load, and finally submit the calculation. According to the working conditions, the crank pin load and the main journal support reaction force are calculated. Through the analysis of the results of crankshaft statics simulation, the weak links of the stress distribution of the crankshaft under dangerous conditions are found, which provides a theoretical basis for the structural design of the crankshaft.

Finite element method modeling of crankshaft axial impact measurements

It has been recently discovered that there is a periodical axial impact phenomenon in a running engine crankshaft. Bending of the shaft causes significant extension of the crankshaft and impact to the engine block through the axial thrust bearing. The aim of this work is to study impact-induced energy fluctuations in a complex-shaped Wärtsilä sixteen vee 32 engine crankshaft by using an explicit finite element method (FEM) during the first 25 ms after impact. Using the FEM allows us to study real components used in industry, and analyze their dynamics in the transient phase. In conclusion, we found interesting results that can be used as guidelines for a full-scale crankshaft measurement instrumentation plan. The full-scale measurements will be performed later in the Wärtsilä Oy facility at Vaasa, Finland. The main finding is that a substantive amount of energy is trapped in the head region and the first two crank pins of the crankshaft, which can affect crankshaft durability regarding high-cycle fatigue.

Low Cycle Fatigue behavior of heat treated EN-47 Spring Steel

EN 47 spring steel is a 1% chromium-vanadium type spring steel, which is widely used for landing gears of smaller aircraft, leaf spring and coil spring of vehicles, heavy machinery crank pin, steering knuckles and disc springs for rigidly bolted sections. In this investigation, E-47 spring steel samples were heat treated and microstructure and hardness were observed. Then the samples were subjected to low cycle fatigue analysis along with fractograph. It is witnessed that for 8hrs heat-treated sample has taken 4222 cycles to fail and that is higher than 4hrs sample which is 3375 cycles to failure and an unheated sample which is having 2856 cycles to failure. The strain controlled fatigue life is greatly influenced by the type crack formation during the fatigue test

Characteristics of Bending Stress with Whirling at the Rear End of a Crankshaft in an Inline 4-Cylinder High Speed Diesel Engine

<div class="section abstract"><div class="htmlview paragraph">As engines become lighter and achieve higher output to meet carbon dioxide emissions targets, it becomes more challenging to design a crankshaft that is both lighter and capable of handling higher loads. Therefore, it is necessary to understand the characteristics of forces imposed on the crankshaft, and the mechanisms by which stresses are created in the crankshaft. This paper describes the characteristics of bending stresses measured on the rearmost crank pin fillet of a crankshaft. Two basic crankshaft resonant modes are described. Forward crankshaft whirl then has the effect of increasing the system natural frequencies by the stiffening effect, while reverse whirl reduces the system natural frequencies by the softening effect. The effect of whirl grows with increasing engine speed. This results in what appears to be four crankshaft natural frequencies rather than two. The four resonances appear at all non-zero engine speeds. The influence of flywheel mass on the stresses and natural frequencies is also described. It is shown that the bending stress in the crank fillet is proportional to the radial force acting on the crank pin. It is also shown that the direction of whirl affects the amplitude of stress imposed by the radial crank pin force, and that the effect of whirl becomes larger as the flywheel inertia is increased. Because increasing engine speed causes more whirl force and moment, engine speed has an influence on bending stress amplitude. Finally, the paper explains why the ratio of crank stress amplitude to radial force varies as a function of the rotational direction of whirl.</div></div>

Failure analysis of the fracture surface of the crankshaft of a vehicle

The purpose of this study was to determine the cause of a fracture in the crankshaft of a 1000 cc gasoline engine. On the broken surface, it could be seen that the cracks started from the direction of the oil hole. A visual examination revealed that there were beach marks on the surface of the fracture, which is usually common in fatigue failure due to a dynamic load. From the test for the chemical composition, it was found that the material was classified as alloy steel. The Rockwell-based material hardness values were different. The highest hardness value of 102.2 HRB was on the outer shell portion of the crankshaft on the x and y axes at points 1 and 14. Finally, it was concluded that the reason for the fracture in the crankshaft was fatigue failure, the material hardness that did not match that of the standard, as well as the initial crack contained within the radius of crank pin number 1.

Design and Simulation of Cracks in A Four-Cylinder Engine Crankshaft Using Finite Element Method

The translational motion of the piston was transformed into a rotational motion by the crankshaft. The combustion resulted in straight thrust in the piston was passed through the piston rod and pushed the crank pin, resulting in a rotational force on the crankshaft. In other words, the crankshaft received high loading and rotated at high speed in each cycle of work. Therefore, crankshafts should be made of high carbon steel with a high endurance limit. The major cause of failure is thermal fatigue since the contact between journal and bearing surface occurred. The contact may result from two reasons: problems of lubrication and use. Based on the factor of safety calculation, crank 1 and 4 were considered to meet the safety criteria because their positions were close to the support of the crankshaft

Finite element analysis for engine crankshaft torsional stiffness

Accurate crankshaft torsional stiffness is important to build the lumped parameter model (LPM) for crankshaft torsional vibration analysis. For the crankshaft system of a four-cylinder in-line gasoline engine, a procedure to build the finite element model (FEM) is presented. And the applicability of two ways to set the equivalent mass or equivalent moment of inertia for piston-rod in FEM is declared. When building a lumped parameter model, the concept of rigid-rotation of the crank pin central section around the central line of the crankshaft is proposed, and a method to obtain the torsional angle of the central section is declared. What is more, three post-processing methods are presented to obtain the torsional stiffness coefficients. According to three load cases of no-load, half load and full load, the tests are carried out. The simulation results of FEM and LPM, and the test results have good agreement with each other.