Piston Model Research Articles

Design and Failure Analysis of Piston Using Ansys

A piston is a component of reciprocating engines. The purpose of piston is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and a connecting rod. It is one of the most complex components of an automobile. In This project we are describes the Thermal analysis by using finite element method (FEM). The specifications used for designing the piston belong to four stroke single cylinder engine of piston. Modeling of piston is done using SOLID EDGE v20. static structural, Thermal and fatigue analysis is performed by using ANSYS WORKBENCH 2022 R1. The parameters used for the simulation are operating gas pressure, material properties of piston. The results predict the maximum stress and strain on pistons using FEA. The best material is selected based on static structural, thermal and fatigue analysis. The analysis results are used to optimize piston geometry of best two Materials

PROFILING THE SURFACE OF THE PIN HOLE IN THE PISTON BODY

Minimization of the mass of the piston kit, which consists of three main parts - piston, pin and connecting rod, is connected, among other things, with the possibility of reducing the diameter of the steel pin. On the other hand, a decrease in its diameter inevitably leads to an increase in stresses in the piston pin hole (PPH) and possible destruction. It is known that reducing the mass of the piston set from 5 to 20% leads to an increase in the output parameters of the internal combustion engine - torque and power by 1% to 4.5%. The purpose of the study is to determine the possibility of reducing the stresses in the bearing due to the profiling of its surface while reducing the diameter of the piston pin. The research algorithm is presented, which consists of building a geometric model of the piston assembly, loading with excessive pressure taking into account the plasticity of the material, modifying the geometry of the PPH and checking the stresses of the loaded state. The conventional piston model has the following geometry: diameter – 80 mm; height – 60 mm; compression height – 30 mm; the diameter of the finger hole is 18 mm; the distance between the bumps is 28 mm. Piston material – aluminum-based alloy – AISI 2014-0, pin and connecting rod material – AISI 1020 steel. Pressure loading conditions: taking into account plasticity – nonlinear, harmonic, 2 cycles, maximum amplitude – 8 MPa; test - static, 6.5 MPa. A crumpling zone with residual deformations was detected in the PPH, the maximum final deformation practically does not differ in the first and second load cycles (0.0081 vs. 0.0084). Residual deformations occur 1/3 of the length from the inner edge of the head. The absolute residual deformations are given in the form of a sweep of the change in the PPH radius. The maximum value is about 0.04 mm. This result is the basis for modifying the geometry of the surface of the finger hole. The modified geometry of the PPH is obtained by boring the cylindrical surface with a profile modeled by the appropriate spline on the geometric model. The boring axis is offset by 0.02 mm from the PPH axis. Verification modeling showed that the averaged loads on the edge of the model are 143 MPa for the cylindrical and 107 MPa for the modified PPH (-25% for the modified profile).

Speech intelligibility prediction based on a physiological model of the human ear and a hierarchical spiking neural network.

A speech intelligibility (SI) prediction model is proposed that includes an auditory preprocessing component based on the physiological anatomy and activity of the human ear, a hierarchical spiking neural network, and a decision back-end processing based on correlation analysis. The auditory preprocessing component effectively captures advanced physiological details of the auditory system, such as retrograde traveling waves, longitudinal coupling, and cochlear nonlinearity. The ability of the model to predict data from normal-hearing listeners under various additive noise conditions was considered. The predictions closely matched the experimental test data under all conditions. Furthermore, we developed a lumped mass model of a McGee stainless-steel piston with the middle-ear to study the recovery of individuals with otosclerosis. We show that the proposed SI model accurately simulates the effect of middle-ear intervention on SI. Consequently, the model establishes a model-based relationship between objective measures of human ear damage, like distortion product otoacoustic emissions, and speech perception. Moreover, the SI model can serve as a robust tool for optimizing parameters and for preoperative assessment of artificial stimuli, providing a valuable reference for clinical treatments of conductive hearing loss.

Muscle Strength Identification Based on Isokinetic Testing and Spine Musculoskeletal Modeling.

Subject-specific spinal musculoskeletal modeling can help understand the spinal loading mechanism during human locomotion. However, existing literature lacks methods to identify the maximum isometric strength of individual spinal muscles. In this study, a muscle strength identification method combining isokinetic testing and musculoskeletal simulations was proposed, and the influence of muscle synergy and intra-abdominal pressure (IAP) on identified spinal muscle strength was further discussed. A multibody dynamic model of the spinal musculoskeletal system was established and controlled by a feedback controller. Muscle strength parameters were adjusted based on the measured isokinetic moments, and muscle synergy vectors and the IAP piston model were further introduced. The results of five healthy subjects showed that the proposed method successfully identified the subject-specific spinal flexor/extensor strength. Considering the synergistic activations of antagonist muscles improved the correlation between the simulated and measured spinal moments, and the introduction of IAP slightly increased the identified spinal extensor strength. The established method is beneficial for understanding spinal loading distributions for athletes and patients with sarcopenia.

Piston structure design and finite element analysis

The working characteristics of internal combustion engines rely on the explosive combustion of fuel in the combustion chamber to drive the piston movement. This working characteristic causes the main component of the combustion chamber, the piston, to bear high thermal and mechanical loads. It has very high requirements for design, manufacturing, and material selection. The working condition of the piston will affect its safety and stability. Therefore, the finite element analysis for the piston is particularly important. Thus, this article first establishes the piston model and divides it into grids in ANSYS, adds boundary conditions, and conducts analysis. The piston thermal analysis mainly includes thermal stress and deformation analysis under thermal load. The piston’s maximal thermal stress is 170.23 MPa and the deformation of thermal expansion is 0.61585 mm. The mechanical stress and deformation analysis under mechanical load are carried out. The maximal stress is 164.91 MPa and the maximal deformation caused by the mechanical stress is 0.24916 mm. Finally, the coupling analysis of thermal and mechanical stress is conducted. The maximal stress is 251.74 MPa, which is located at the outskirt margin of the piston pinhole. The maximal deformation is 0.60779 mm. The simulation analysis results indicate that the method proposed in this article provides a way to design the structure of similar automotive components such as pistons.

Design and Analysis of Piston by using Ansys Workbench

Abstract: In this study, structural analysis is investigated on conventional piston made of cast iron. Secondly analysis are performed on piston made of aluminum, titanium alloy , structural steel and fiber glass. The material used for the design of piston should have light weight, low cost, structurally and thermally withstand at very high pressure and temperature condition that will occur in combustion process. In this project, It has been decide to study a particular piston design And its capability for maximum gas pressure. In this work, initial planning is to make piston model using solid modeling software CATIA V5. It has been decided to mesh the geometry analyze using ANSYS. For the analysis of piston input conditions and process of analysis, a lot of literature survey has been done. High combustion gas pressure will act as a mechanical loads and causes major stresses in the critical region of the piston. Detailed static structural analysis is carried out for various loading conditions like maximum gas pressure load.

Energy recovery from landfill gas emissions using a stepped piston segregated scavenge engine

Atmospheric landfill gas emissions present serious problems when trying to counter the effects of global warming. The main constituent of landfill gas is methane, a more damaging greenhouse gas than CO2. European Union directives require the control and collection of landfill gases and promote energy recovery via combustion of the gas. A key challenge for combustion of landfill gas is the highly corrosive nature of the gas constituents which causes heightened maintenance and failure of applied engine systems. Conventional engines suffer from the effects of corrosion; however, stepped piston engine technology has yet to be considered for operational use at landfill sites. The engine has inherent advantages for such an application when compared with current conventional engines. The engine allows improved lubricating oil health compared to conventional engines and hence reduced oil use. This study discusses the challenges along with modelling of stepped piston and equivalent four-stroke engine solutions.

Accelerating model evaluations in uncertainty propagation on tensor grids using computational graph transformations

Methods such as non-intrusive polynomial chaos (NIPC), and stochastic collocation are frequently used for uncertainty propagation problems. Particularly for low-dimensional problems, these methods often use a tensor-product grid for sampling the space of uncertain inputs. A limitation of this approach is that it encounters a significant challenge: the number of sample points grows exponentially with the increase of uncertain inputs. Current strategies to mitigate computational costs abandon the tensor structure of sampling points, with the aim of reducing their overall count. Contrastingly, our investigation reveals that preserving the tensor structure of sample points can offer distinct advantages in specific scenarios. Notably, by manipulating the computational graph of the targeted model, it is feasible to avoid redundant evaluations at the operation level to significantly reduce the model evaluation cost on tensor-grid inputs. This paper presents a pioneering method: Accelerated Model Evaluations on Tensor grids using Computational graph transformations (AMTC). The core premise of AMTC lies in the strategic modification of the computational graph of the target model to algorithmically remove the repeated evaluations on the operation level. We implemented the AMTC method within the compiler of a new modeling language called the Computational System Design Language (CSDL). We demonstrate the effectiveness of AMTC by using it with the full-grid NIPC method to solve four low-dimensional UQ problems involving an analytical piston model, a multidisciplinary unmanned aerial vehicle design model, a multi-point air taxi mission analysis model, and a single-disciplinary rotor model, respectively. For three of the four test problems, AMTC reduces the model evaluation cost by between 50% and 90%, making the full-grid NIPC the most efficacious method to use among the UQ methods implemented.

Determination of gas parameters in resonant pipes and channels of engines with a periodic workflow using the piston analogy method

This paper investigates a process of gas flow in the resonant tube of an engine with a periodic workflow. Analysis of various flow models and comparison of known data have shown that the problems of constructing closed 0-dimensional models of the operating cycle for some types of engines remain unresolved. Given this, the question arises about the dimensionality of models of individual engine elements, including the resonant pipe model, which must be included in the general model of the cycle, especially at the initial stage of its development. To solve the identified problems, a mathematical model of air flow has been improved, built on the basis of an analogy with a '"liquid" piston. Unlike existing ones, the piston analogy model allows one to calculate the instantaneous velocity averaged over the length of the pipe using a numerical solution of the differential equation for velocity. To test the model built, an alternative finite-difference 1-dimensional gas-dynamic model was selected, with the help of which a test simulation of air flow in a pipe was performed. It has been established that the piston model allows one to find the flow velocity with an accuracy of 5 % for a pressure drop varying according to a sinusoidal law. The permissible limits for changes in the oscillation frequency and pipe length were found, at which the piston model has a minimum error. Based on the results of the study, it was concluded that with a small mass and inertia of the liquid piston, the proposed model gives results close to those provided by more complex models with higher dimensionality. This indicates the possibility of using a piston model for elements such as pipes as part of a 0-dimensional thermodynamic model of engines with a periodic operating process as an approximate alternative to traditional 1-dimensional flow models

Finite element-based diffraction correction for piezoelectric transducers accounting for diffraction at transmission, propagation, and reception.

Existing diffraction correction models for ultrasonic transmit-receive measurement systems rely on simplifying assumptions with respect to the boundary conditions at the transmitter or receiver. Common simplifications include approximating the sound field radiated by a piezoelectric transducer using a baffled piston model and assuming that the receiver's electrical response is proportional to the spatially averaged free-field pressure over its front surface. In many applications, such simplifications may be adequate, but their validity and accuracy need to be evaluated and quantified. Here, a diffraction correction model utilizing the full set of electrical and mechanical boundary conditions at the transmitter and receiver is presented, avoiding these simplifications. The model is based on finite element modeling of coaxially aligned piezoelectric transducers in a fluid medium. Comparison is made with existing models for an example case of cylindrical piezoelectric ceramic disk transducers operating in air at 50-300 kHz and 0.03-2 m apart, relevant for, e.g., sound velocity and absorption measurements in fluids and ultrasonic gas flow metering. In the near-field, errors introduced by the simplifications are up to 3 dB and 47° for the first radial resonance. Generally, such errors are application-specific and depend on distance, frequency, transducer construction, vibration pattern, and medium properties.

Comparative Study and Static Analysis of Piston Using Solid Edge and Ansys

Abstract: A piston is a component of reciprocating engines. The purpose of piston is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and a connecting rod. It is one of the most complex components of an automobile. In This project we are describes the Thermal analysis by using finite element method (FEM). The specifications used for designing the piston belong to four stroke single cylinder engine of piston. Modeling of piston are done using SOLID EDGE v20. static structural, Thermal and fatigue analysis is performed by using ANSYS WORKBENCH 2022 R1. The parameters used for the simulation are operating gas pressure, material properties of piston. The results predict the maximum stress and strain on pistons using FEA. The best material is selectedbased on static structural, thermal and fatigue analysis. The analysis results are used to optimize piston geometry of best two Materials.

Design and Failure Analysis of Piston

Abstract: A piston is a component of reciprocating engines. The purpose of piston is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and a connecting rod. It is one of the most complex components of an automobile. In This project we are describes the structural analysis of five different aluminum alloy pistons, by using finite element method (FEM). The specifications used for designing the piston belong to four stroke single cylinder engine of Bajaj Pulsar 220cc. Modeling of various aluminium alloy piston are done using SOLID EDGE. Static structural, thermal and fatigue analysis is performed by using ANSYS WORKBENCH 2022 R1. The parameters used for the simulation are operating gas pressure, material properties of piston. The results predict the maximum stress and strain on different aluminium alloy pistons using FEA. The best aluminum alloy material is selected based on static structural, thermal and fatigue analysis. The analysis results are used to optimize piston geometry of best aluminum alloy.

Three-dimensional CFD-solid mechanics analysis of the hydrogen internal combustion engine piston subjected to thermomechanical loads

Fueling internal combustion engines with hydrogen is one of the most recommended alternative fuels today in order to combat the energy crisis, pollution problems, and climate change. Despite all the advantages of hydrogen fuel, it produces a higher combustion temperature than gasoline. In an internal combustion engine, the piston is among the numerous complex and highly loaded components. Piston surfaces are directly affected by combustion flames, making them critical components of engines. To examine the stress distribution and specify the critical fracture zones in the piston for hydrogen fuel engines, a three-dimensional CFD-solid-mechanics model of the internal combustion engine piston subjected to real thermomechanical loads was analyzed numerically to investigate the distribution of the temperature on the piston body, the interrelated thermomechanical deformations map, and the pattern of the stresses when fueling the engine with hydrogen fuel. With the aid of multiphysics COMSOL software, the CFD-solid-mechanics equations were solved with high accuracy. Despite the increase in pressure on the piston and its temperature when the engine is running on hydrogen fuel, the results show that the hydrogen fuel engine piston can withstand, safely, the thermomechanical loads. In comparison to gasoline fuel, hydrogen fuel caused a deformation of 0.34 mm, an increase of 17%. This deformation is within safe limits, with an average clearance of 0.867 mm between the cylinder liner and piston.

Modeling the acoustic radiation of plates using circular pistons

We propose an equivalent piston model (EPM) for estimating the modal radiation efficiency of complex-shaped plates. In this model, the structure is not discretized into small elementary radiators. Instead, it involves determining the minimum number, size, volume velocity, and position of vibrating pistons that radiate in accordance with the mode shape they emulate, i.e. one piston per lobe within the mode shape, regardless the plate’s shape. For shapes relatively close to rectangles, a specific version of the method is proposed by representing the shape only by two characteristic lengths (EPM-RD), and paving the virtual surface with pistons vibrating at alternate phases along a rectangular grid. The validity of this assumption is evaluated in terms of shape dissymmetry, which can cause residual radiators to appear, and where the dissymmetry can affect the spatial distribution of lobes. With a known spatial distribution mimicking the mode shapes, it is possible to estimate also average values of radiation parameters, such as the average radiation efficiency and time-average mean power. The average radiation efficiency and power follow the Equipartition Theorem and allow the calculation to be performed without cross-terms and using only the modal efficiencies and resonance frequencies. Due to their simplicity and ease of implementation, piston-based equivalent models have great potential for solving radiation problems from flat structures. Any mode shape can be modeled with vibrating pistons and analytical formulations can be easily derived, even for complex geometries. Moreover, with EPM-RD, average values can also be calculated, which provides an estimation of average radiated properties within seconds without requiring any integration or large matrices to be solved.

Impact of hohlraum cooling on ignition metrics for inertial fusion implosions

This paper extends the evaluation of ignition metrics to include the impact of hohlraum cooling before peak implosion velocity in radiation driven implosions. First, we provide an extension of the results for the key hot spot stagnation quantities from the 2018 paper [Lindl et al., Phys Plasmas 25, 122704 (2018)]. The modified analytic expressions presented here match the Hydra results for these National Ignition Facility scale implosions both with and without hohlraum cooling before peak velocity if the effective ablation pressure Pabl(effective) = Pabl(tpv − 0.5 ns) is used in the analytic formulas, where tpv is the time of peak implosion velocity. Second, we provide an analysis that enables a comparison of the Hydra radiation hydrodynamics code calculations utilized here with the predictions of the analytic piston model [Hurricane et al., Phys. Plasmas 29, 012703 (2022)] of an ICF implosion, which focused on sensitivity to time duration of the hohlraum cooling phase before peak velocity (often called the “coast time”) and the shell radius at peak velocity Rpv. Third, we provide a set of ignition metrics that are valid across a wide range of capsule designs valid for implosions both with and without hohlraum cooling before peak implosion velocity is reached.

Frictional moment and wear modelling for incomplete spherical pistons in a spherical pump

PurposeBecause of the specific structure and working mechanism, piston speed is only half of its shaft, which causes severally friction between piston and cylinder. Therefore, the main purpose of this paper is to investigate the friction and wear characteristics of the incomplete spherical piston in spherical pump comprehensively. Finally, to search the low-friction and wear-resistance structural pattern of the piston, and enhance the durability of spherical pump.Design/methodology/approachThe non-linear frictional moment model for incomplete spherical piston in spherical pump was derivated quantificationally. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The theoretical wear model of piston–cylinder pair is proposed as well.FindingsTo reduce the frictional moment between incomplete piston and cylinder, the optimised diameter ratio between piston pin and piston should be 0.12 based on the parameter sensitivity analyses. The maximum frictional moment is approximately 2.5 times of the minimum. The total efficiency should be considered synthetically based on the thickness of specific working medium.Originality/valueThe proposed non-linear frictional moment model offers the quantitative estimations. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The wear behaviours of the piston and cylinder were analysed to investigate the wear characteristics of the piston.

Surrogate Models for the Prediction of Damping Ratios in Coupled Acoustoelastic Rotor-Cavity Systems

Abstract Centrifugal compressors are versatile machines that many industries employ for a wide range of different applications, including the production of highly compressed gases. During the last decades, comprehensive research was conducted on the impact of high-pressure operating conditions on the vibrational behavior of radial compressors. In various studies, acoustic modes building up in the side cavities were found to be a potential source of high cycle fatigue. Nowadays, it is well-known that an increase in gas pressure levels leads to a more pronounced fluid–structure interaction between the side cavities and the impeller resulting in a frequency shift of the acoustic and structural modes. In a recently published paper, the authors presented a generalized model which can predict this behavior. As it is not always possible to avoid operating close to or accelerating through a resonance, it is crucial to know the damping present within the system. Currently, only few publications concentrate on the damping of radial impellers. Therefore, the authors present measurement data acquired from a test rig at the University of Duisburg-Essen, which reveals the damping behavior of a disk under varying operating conditions. Two surrogate models are proposed to predict the identified damping behavior. The first one is based solely on a one-dimensional piston model and the second approach uses an enhanced version of the generalized method. Finally, the measurement data are used to validate both surrogate systems.

Modelling of a Conventional Piston of a Single Cylinder Four-Stroke Diesel Engine by Using SolidWorks

This paper presents a 3D modelling of a conventional piston of a single cylinder four-stroke diesel engine using ZS1115NM diesel engine specification. Piston in internal combustion engine (ICE) is a circular piece of metal which converts the rotary movement of the crankshaft into reciprocating motion thereby exerting a force on the air-fuel mixture in the cylinder. It converts thermal energy into mechanical energy in an internal combustion engine (ICE). The methodology applied was analytical design and modelling of the piston using SOLIDWORKS 2013 3D Computer Aided Design (CAD) software. This method was used because it provided a step by step designing of the various elements of the piston. The material chosen for the piston is an aluminium alloy designated as A92618 or simply A2618, due majorly to its high coefficient of thermal expansion (CTE) which enables the piston withstand high thermal stress without cracking or failure. Another important reason is that it has a high thermal conductivity (approximately 3 times than that of cast iron). It is seen that with given engine specification a suitable material for designing a conventional piston is chosen and the model manufactured. Keywords— 3D modelling, ZS1115NM, Internal combustion engine, SOLIDWORKS 2013, A2618, Coefficient of thermal expansion

Evaluation of High-Temperature Martensitic Steels for Heavy-Duty Diesel Piston Applications

<div class="section abstract"><div class="htmlview paragraph">Five different commercially available high-temperature martensitic steels were evaluated for use in a heavy-duty diesel engine piston application and compared to existing piston alloys 4140 and microalloyed steel 38MnSiVS5 (MAS). Finite element analyses (FEA) were performed to predict the temperature and stress distributions for severe engine operating conditions of interest, and thus aid in the selection of the candidate steels. Complementary material testing was conducted to evaluate the properties relevant to the material performance in a piston. The elevated temperature strength, strength evolution during thermal aging, and thermal property data were used as inputs into the FEA piston models. Additionally, the long-term oxidation performance was assessed relative to the predicted maximum operating temperature for each material using coupon samples in a controlled-atmosphere cyclic-oxidation test rig. A current commercial steel piston alloy, quenched and tempered martensitic steel 4140, was tested in a single-cylinder research engine for a baseline oxidation and mechanical performance assessment using an abbreviated (50h) durability test plan. The predicted suitability of a candidate piston material in an engine is primarily based on its elevated temperature strength, oxidation resistance, and the complex influence of thermal conductivity, the latter of which is substantially lower for the candidate materials considered in this research relative to the traditional alloys. Although the lower thermal conductivity causes the candidate alloys to operate in higher temperature ranges under identical engine operating conditions and piston geometries, increasing the likelihood of partially or completely negating their strength and oxidation resistance advantages relative to 4140 and MAS steels, this evaluation indicates that several of the candidate piston alloys are predicted to enable improved oxidation resistance under more severe engine operating conditions relative to the current piston materials. However, further evaluation is required to determine if the elevated temperature fatigue strength and durability of these alloys are suitable for more severe engine conditions.</div></div>

Effects of different piston combustion chamber heights on heat transfer and energy conversion performance enhancement of a heavy-duty truck diesel engine

The heat transfer and energy conversion characteristics of 3 kinds of pistons are studied based on the heat load prediction model of diesel engine piston. Thermal energy conversion effects of pistons for heavy-duty truck engine performance are investigated which involve air-fuel ratio, intake flow, exhaust temperature and fuel consumption. The research results illustrate the whole temperatures and heat flux of piston rise with increase of piston combustion chamber height. The maximum and the minimum temperature difference are 18.34 K and 3.07 K of piston-12, piston-15 and piston-18 with the piston wall surface temperature change dramatically. Maximum heat flux (1 203 500 W/m2, 1 488 500 W/m2, 1 523 200 W/m2) and the minimum heat flux (761.37 W/m2, 990.41 W/m2, 1325.2 W/m2) of piston-12, piston-15 and piston-18 are conspicuously conspicuously different with piston wall surface heat flux significant change. Piston-18 has the characteristics of large air-fuel ratio (27.3) and intake flow (844.33 kg/h), low fuel consumption (217.3 g/kW·h) and exhaust temperature (776.8 K), which shows that it is more efficient and the heat energy conversion capability is improved remarkably. The appropriate piston chamber height can improve heat transfer and energy conversion performance.