Browse Topic: Analysis methodologies

Items (9,295)
Software reliability prediction involves predicting future failure rates or expected number of failures that can happen in the operational timeline of the software. The time-domain approach of software reliability modeling has received great emphasis and there exists numerous software reliability models that aim to capture the underlying failure process by using the relationship between time and software failures. These models work well for one-step prediction of time between failures or failure count per unit time. But for forecasting the expected number of failures, no single model will be able to perform the best on all datasets. For making accurate predictions, two hybrid approaches have been developed—minimization and neural network—to give importance to only those models that are able to model the failure process with good accuracy and then combine the predictions of them to get good results in forecasting failures across all datasets. These models once trained on the dataset are
Mahdev, Akash RavishankarLal, VinayakMuralimohan, PramodReddy, HemanjaneyaMathur, Rachit
This study focuses on the numerical analysis of weather-strip contact sealing performance with a variable cross-sectional design, addressing both static and dynamic behaviors, including the critical issue of stick-slip phenomena. By employing finite element modeling (FEM), the research simulates contact pressures and deformations under varying compression loads, DCE (Door Closing Efforts) requirements, typical in automotive applications. The analysis evaluates how changes in the cross-sectional shape of the weather-strip affect its ability to maintain a consistent sealing performance, especially under dynamic vehicle operations. The study also delves into stick-slip behavior, a known cause of noise and vibration issues, particularly improper/ loosened door-seal contact during dynamic driving condition. This study identifies key parameters influencing stick-slip events, such as friction coefficients, material stiffness, surface interactions, sliding velocity, wet/dry condition
Ganesan, KarthikeyanSeok, Sang HoSun, Hyang Sun
The multifaceted, fast-paced evolution in the automotive industry includes noise and vibration (NVH) behavior of products for regulatory requirements and ever-increasing customer preferences and expectations for comfort. There is pressing need for automotive engineers to explore new and advanced technologies to achieve a ‘First Time Right’ product development approach for NVH design and deliver high-quality products in shorter timeframes. Artificial Intelligence (AI) and Machine Learning (ML) are trending transformative technologies reshaping numerous industries. AI enables machines to replicate human cognitive functions, such as reasoning and decision-making, while ML, a branch of AI, employs algorithms that allow systems to learn and improve from data over time. The purpose of the paper is to show an approach of using machine learning techniques to analyze the impact of variations in structural design parameters on vehicle NVH responses. The study begins by executing the Design of
Miskin, Atul R.Parmar, AzanRaj, SoniaHimakuntla, Uma Maheswar
During cylinder deactivation events, high amplitude torque pulsations are generated at the crankshaft of the engine over a wide frequency range creating a potential risk for noise, vibration and harshness (NVH) performance of the vehicle. As passive tuned mass dampers are effective only in a narrow frequency range, active tuned mass dampers (ATMD) have become a popular choice to mitigate the risk. Often, engineers rely on finite element (FE) models of vehicle structures to make design decisions during the early stages of vehicle development. However, there is limited literature on the simulation of ATMD using FE techniques. Consequently, several details related to the ATMD design are decided through physical testing at the latter stages of vehicle development which is not ideal. To address these issues, a novel methodology to simulate an ATMD during cylinder deactivation events using FE technique is presented here. In this study, an ATMD based on force feedback control method was
Maddali, RamakanthMogal, Akbar BaigHaider, SyedJahangir, Yawar
As India’s economy expands and road infrastructure improves, the number of car owners is expected to grow substantially in the coming years. This market potential has intensified competition among original equipment manufacturers (OEMs) to position their products with a focus on cost efficiency while delivering a premium user experience. Noise and Vibration (NV) performance is a critical differentiator in conveying a vehicle's premiumness, and as such, NV engineers must strategically balance the achievement of optimal acoustic performance with constraints on cost, mass, and development timelines. Traditionally, NV package optimization occurs at the prototype or advanced prototype stage, relying heavily on physical testing, which increases both cost and time to market. Furthermore, late-stage design changes amplify these challenges. To address these issues, this paper proposes the integration of Hybrid Statistical Energy Analysis (HSEA) into the early stages of vehicle development
Rai, NiteshMehta, MakrandRavindran, Mugundaram
While many individual technical descriptors exist to quantify and describe different kinds of acoustic phenomena, they each only describe the technical aspects of a sound itself without considering any additional non-acoustic context. Human perception, however, is greatly informed by this context. For example, humans have different expectations for the sound of an electric razor than they do for an internal combustion engine, despite both objects being able to be described by sound pressure level or a measure of roughness. No single technical descriptor alone works in all contexts as a gold standard which objectively determines whether a sound is “good.” Jury tests, however, are a great aid towards gaining a measure of this context. When seeking to effectively quantify the sound quality of a device, it is necessary to combine the perceptive information from the results of a jury test alongside one or more technical descriptors in order to provide a meaningful method of evaluation. The
Thiede, Shane
When a vehicle is driven at high speed, there exists intricate flow pattern and vortex shedding at the side window area with intense pressure fluctuation. A significant dynamic pressure difference between the vehicle's exterior and interior can render the side window sealing system vulnerable to aspiration. This susceptibility can lead to the generation of leakage noise, adversely affecting acoustic comfort in the vehicle's cabin. This paper delves into the aspiration properties of glassrun seal system under time-varying pressure difference. A nonlinear finite element model of the glassrun seal was established to simulate the quasi-static deformation of the sealing strip during installation process, which aims to obtain the deformed geometric shape and residual stress after this process. Then, the exterior flow field of the glassrun sealing area of a simplified vehicle model was calculated with CFD simulation to obtain the hydrodynamic pressure excitation acting on the outer surface of
Li, HanqiHe, YinzhiZhang, LijunZhang, YongfengYu, WuzhouJiang, ZaixiuBlumrich, ReinhardWiedemann, Jochen
Squeak and Rattle (S&R) issues present significant challenges in the automotive industry, negatively affecting the perceived quality of vehicles. Early identification of these issues through rigorous testing protocols—such as auditory assessments and dynamic simulations—enables the development of more robust systems while optimizing resource use. Finite Element Method (FEM) simulations are crucial for identifying S&R issues during the design phase, allowing engineers to address potential problems before the creation of physical prototypes. By developing high-fidelity virtual models and accurately simulating flexible connections, these simulations effectively capture rattle effects, enhancing prediction reliability. Traditional snap stiffness calculations typically employ a cantilever-based formulation, which is suitable for simple snap-fit designs but insufficient for more complex geometries that require enhanced stiffness. To address this limitation, the proposed methodology utilizes
Rao, SohanElangovan, PraneshReddy, Hari
Two wheeler is important and essential transportation mode in many of the countries across the globe. Designing a motorcycle with better riding comfort and minimal vibration are thus a major challenge for engineers now a day. Engine and road excitations are two source of vibration acting on motor bike or scooter both. These vibrations are transmitted to the chassis, sub chassis, aesthetic parts and then to the rider and pillion. Unwanted vibrations will create discomfort to the rider/pillion and produce noise. Hence, these need to be minimized. This study is focus on diagnosis and control of output vibration response of sub chassis/aesthetic parts due to engine unbalanced excitation force. There are numerous parameter of motor bike/scooter that governs the vibration response of sub chassis/aesthetic parts. Engine unbalanced inertia force characteristics and their transmission to rider and pillion has been studied and reported here. Environmental benefit demands for a complete noise
Khare, Saharash
Every vehicle has to be certified by the concerned governing authority that it matches certain specified criteria laid out by the government for all vehicles made or imported into that country. Horn is one of the components that is tested for its function and sound level before a vehicle is approved for production and sale. Horn, which is an audible warning device, is used to warn others about the vehicle’s approach or presence or to call attention to some hazard. The vehicle horn must comply with the ECE-R28 regulation [1] in the European market. Digital simulation of the horn is performed to validate the ECE-R28 regulation. In order to perform this, a finite element model of a cut model of a vehicle, which includes the horns and other components, is created. Fluid-structure coupled numerical estimation of the sound pressure level of the horn, with the appropriate boundary conditions, is performed at the desired location as per the ECE-R28 regulation. The simulation results thus
Ramachandran, BalachandarRaveendran, RoshinMondal, Arghya
Based on the objective and subjective experiment and finite element analysis, the influencing factors on the door closing sound quality of a heavy truck is analyzed and optimized. Results show that the loudness and sharpness can be reduced by increasing stiffness and damping of the door. The sound quality can be enhanced by increasing the pressure release area, which can decrease the air pressure resistance of dooring closing. By adding holes on the inner liner and changing the pressure release location, the dooring closing air pressure resistance is reduced from 289 Pa to 181 Pa. In terms of the rebound sound, the sound level is positively related to the door closing force. Increasing the protrusion height and decreasing the stiffness of the vibration absorber of the handle can improve the rebound sound quality. Optimizing the absorbers on both ends of the handle and adding damping material can decrease the loudness by 47.8%, reduce the cavity sound, reduce the rattle and improve the
Wang, JianZhang, YongshenFeng, LeiXie, ChenhaoLin, JieweiSun, Changchun
The application of virtual point transformation for determining the transfer dynamic stiffness of a helical coil spring is demonstrated in this experimental study. Rigid fixtures are attached to both ends of the spring, and frequency response functions are measured using impact hammer excitations. These frequency response functions are transformed into virtual points, analogous to a node in finite element analysis, with six degrees of freedom. The six degrees of freedom transfer dynamic stiffness is then extracted using the inverse substructuring method, which eliminates the need to account for fixture dynamics. The results are validated by a direct measurement approach. Additionally, the study investigates the effect of liquid applied sprayed damping coatings on the spring's transfer dynamic stiffness, revealing that the coating significantly reduces vibration amplitudes at the surge frequencies. This suggest that the springs effective damping properties are enhanced.
Neihguk, DavidHerrin, D. W.de Klerk, Dennis
Pulse width modulation (PWM) and the corresponding modulation index (MI) value are of critical importance to the performance of electric drive systems for electric vehicle applications. For interior permanent magnet (IPM) machines, operating in overmodulation (OVM) and six-step modes increases the voltage output beyond the linear region, allowing the motor to achieve higher torque and power with reduced inverter loss. However, the resulting distorted current waveforms and higher current ripple harmonics lead to a notable increase in the motor noise. A multi-disciplinary approach has been developed to analyze the NVH performance of a three-phase 8-pole IPM motor when it operates in the OVM and six-step regions at high speed. The PWM current ripple harmonics induced by voltage-source inverters are predicted using different MIs and subsequently validated through experiments. The current ripple data are used for the prediction of dynamic electromagnetic (EM) forces in the OVM and six-step
He, SongChang, LeGong, ChengZhang, PengGSJ, Gautam
The proposed work performs the detailed investigation of material damping ratio for different Electronic Ignition Switch Module (EISM) used in two-wheeler automobiles. A Finite Element Method (FEM) based simulation model has been developed. The simulation is performed by matching the failure areas of critical components in the assembly with physical sinusoidal vibration based shaker table test. The results (particularly breakage) have been reproduced by utilizing different damping ratios for the assembly. The damping ratio parameter is further utilized to perform FEM based harmonic response analysis for different EISM and evaluate critical structural breakage zones. The breakage zones predicted by simulation are found to be aligned with breakage zones depicted by shaker table sinusoidal test results. The simulation outcomes are validated, specifically considering the damping ratio parameter. The FEM based harmonic response analysis has been performed for a particular acceleration
Shah, VirenKalurkar, ShantanuKumar, RahulKushari, SubrataMiraje, JitendraD, SureshParandkar, Parag
This paper investigates the performance of a dissipative material compared to conventional acoustic materials under conditions that simulate real-world vehicle applications with acoustic leakage. Various acoustic materials were evaluated through laboratory experiments, which included acoustic leakage in both the steel panel and the acoustic materials. Acoustic leakages commonly occur in actual vehicle conditions at pass-throughs or fastener mounting locations. The study also presents in-vehicle test results to demonstrate the effectiveness of the dissipative material in managing acoustic leakage.
Yoo, TaewookMaeda, HirotsuguSawamoto, KeisukeAnderson, BrianGan, KimTongHerdtle, Thomas
Electric vehicles (EVs) are shaping the future of mobility, with drive motors serving as a cornerstone of their efficiency and performance. Motor testing machines are essential for verifying the functionality of EV motors; however, flaws in testing equipment, such as gear-related issues, frequently cause operational challenges. This study focuses on improving motor testing processes by leveraging machine learning and vibration signal analysis for early detection of gear faults. Through statistical feature extraction and the application of classifiers like Wide Naive Bayes and Coarse Tree, the collected vibration signals were categorized as normal or faulty under both loaded (0.275 kW) and no-load conditions. A performance comparison demonstrated the superior accuracy of the wide neural networks algorithm, achieving 95.3%. This methodology provides an intelligent, preventive maintenance solution, significantly enhancing the reliability of motor testing benches.
S, RavikumarSharik, NSyed, ShaulV, MuralidharanD, Pradeep Kumar
Bearings are fundamental components in automotive systems, ensuring smooth operation, efficiency, and longevity. They are widely used in various automotive systems such as wheel hubs, transmissions, engines, steering systems etc. Early detection of bearing defects during End-of-Line (EOL) testing and operational phases is crucial for preventive maintenance, thereby preventing system malfunctions. In the era of Industry 4.0, vibrational, accelerometer, and other IoT sensors are actively engaged in capturing performance data and identifying defects. These sensors generate vast amounts of data, enabling the development of advanced data-driven applications and leveraging deep learning models. While deep learning approaches have shown promising results in bearing fault diagnosis, they often require extensive data, complex model architectures, and specialized hardware. This study proposes a novel method leveraging the capabilities of Vision Language Models (VLMs) and Large Language Models
Chandrasekaran, BalajiCury, Rudoniel
A good Noise, Vibration, and Harshness (NVH) environment in a vehicle plays an important role in attracting a large customer base in the automotive market. Hence, NVH has been given significant priority while considering automotive design. NVH performance is monitored using simulations early during the design phase and testing in later prototype stages in the automotive industry. Meeting NVH performance targets possesses a greater risk related to design modifications in addition to the cost and time associated with the development process. Hence, a more enhanced and matured design process involves Design Point Analysis (DPA), which is essentially a decision-making process in which analytical tools derived from basic sciences, mathematics, statistics, and engineering fundamentals are used to develop a product model that better fulfills the predefined requirement. This paper shows the systematic approach of conducting a Design Point Analysis-level NVH study to evaluate the acoustic
Ranade, Amod A.Shirode, Satish V.Miskin, AtulMahamuni, Ketan J.Shinde, RahulChowdhury, AshokGhan, Pravin
Thermal Management Integration Module (TMIM), which comprises components such as water pumps, runner boards, brackets, sensors, etc., is a multifunctional integrated component for electric vehicles. However, the water pump generates an excitation over a wide range of frequencies due to a wide range of speed variations. This excitation causes the TMIM to vibrate and generate noise. In this study, a TMIM that generates noise is studied and analyzed. Using the TMIM of an electric vehicle as a case study, a full-vehicle experimental test was conducted, revealing that the noise originates from the integration module. The finite element method is used to analyze the cause of noise generation. Given the characteristics of the TMIM, which comprise many components, high integration, and a complex structure, this paper simplifies the bracket, heat exchanger, sensor, and other components using the centralized mass point method. The modal state of the TMIM is obtained by impact hammer testing the
Xu, Shenao
Low density polyurethane foam was first proposed as an alternative to expandable baffles and tapes for sealing vehicle body cavities towards the end of the last century. Despite several inherent advantages for cavity sealing, the high equipment cost of dispensing amongst other reasons, this technology has not spread as widely as expected. With the advent of electric vehicles, there is an increased emphasis on controlling higher frequencies from motors, inverters and other components, and polyurethane foam can be a viable solution by providing more robust sealing. Polyurethane foam sealing is already being employed in the new breed of electric vehicles, but its NVH advantages have not been fully studied or published in literature. Using an existing electric vehicle with conventional expandable baffles & tape sealing measures, a comprehensive evaluation of NVH performance using the closed-cell polyurethane foam solution was conducted. Testing included component level bench test on body
Kavarana, FarokhGuertin, Bill
To enhance the power density of the system and reduce production costs, the high-speed electric drive system featuring integrated design and control is poised to be the future development trend. However, the high speeds of motors and gear reducers can lead to challenges such as system reliability and issues related to NVH. This paper specifically addresses the NVH concerns associated with the in-wheel reducer and motor drive system (IWRMDS). First, a bench test scheme is established, and vibration and noise tests are conducted under a range of conventional operating conditions. The results indicate that at a torque of 200 Nm and a speed of 5500 rpm, the noise sound pressure level reaches 86.2 dB, highlighting significant vibration and noise issues within the system. Subsequently, Operational Deflection Shape (ODS) testing and analysis are performed on the system. It was discovered that the IWRMDS exhibits a relatively rich modal frequency spectrum, with the breathing mode being the
Huang, ChaoXiong, LuMeng, DejianGong, YuGuo, HanZhang, Mengyuan
The trend towards electrification propulsion in the automotive industry is highly in demand due to zero-emission and becoming more significant across the world. Battery electric vehicles have lower overall noise as compared to conventional I.C Engine counterparts due to the absence of engine combustion and mechanical noise. However, other narrowband and tonal noises are becoming dominant and are strongly perceived inside the cabin. With the ongoing push towards electrification, there is likely to be increased focus on the noise impact of gearing required for the transmission of power from the electric motor to the road. Direct coupling of E-motors with Axle has resulted in severe tonal noises from the driveline due to instant e-motor torque ramp up from 0 rpm and reverse torque on driving axle during regenerative braking. The tonal noises from the rear axle during vehicle running become very critical for customer perception. For automotive NVH engineers, it has become a challenge to
Doshi, SohinKalsule, DhanajiSawangikar, PradeepSuresh, VineethSharma, Manish
Electric motor whine is a significant source of noise in electric vehicles (EVs). To improve the noise, vibration, and harshness (NVH) performance of electric propulsion systems, it is essential to develop a physics-based, high-fidelity stator model. In this study, a machine learning (ML) model is developed using an artificial neural network (ANN) method to accurately characterize the material properties of the copper winding, varnish, and orthotropic stator laminate structure. A design of experiments (DOE) approach using Latin hypercube sampling of parameters is implemented after evaluating alternative surrogate models. A finite element (FE) model is constructed using the nominal stator design parameters to train the ANN model using 121 DOE variables and 72,000 data points. The ML-trained ANN model is then verified to predict the driving point frequency response function (FRF) spectrum with reasonable accuracy. Subsequently, modal tests are conducted on the electric stator, and the
Rao, Bhyri RajeswaraGSJ, GautamHe, Song
In the era of Industry 4.0, the maintenance of factory equipment is evolving with new systems using predictive or prescriptive methods. These methods leverage condition monitoring through digital twins, Artificial Intelligence, and machine learning techniques to detect early signs of faults, types of faults, locations of faults, etc. Bearings and gears are among the most common components, and cracking, misalignment, rubbing, and bowing are the most common failure modes in high-speed rotating machinery. In the present work, an end-to-end automated machine learning-based condition monitoring algorithm is developed for predicting and classifying internal gear and bearing faults using external vibration sensors. A digital twin model of the entire rotating system, consisting of the gears, bearings, shafts, and housing, was developed as a co-simulation between MSC ADAMS (dynamic simulation tool) and MATLAB (Mathematical tool). The gear and bearing models were developed mathematically, while
Rastogi, SarthakSinghal, SrijanAhirrao, SachinMilind, T. R.
This research optimizes sheet metal gusset geometry to support a suspension pickup point in a Formula SAE racecar. The sheet metal gusset design incorporates an external radial cut-out and an internal triangular cut-out, each of which can be adjusted in size to optimize the stiffness to mass ratio. A finite element analysis was set up using a heavy braking load case, which applied 3900 N to the suspension point being supported by the gusset. A parametric optimization (finite element analysis) was run in SolidWorks to gather mass and stiffness data for each of the 143 designs under the prescribed load case. The parametric optimization was run on both a simulated front hoop and a test fixture, which showed a similar trend in their results. Experimental testing was performed on three designs. The gusset profiles were waterjet and TIG welded to the test fixture tube frames. The results of the test agreed with the simulation results with a discrepancy of less than 10% in all cases. The
Burggraf, JacobWillerth, Stephanie MichelleYu, Bosco
This article conducts a thorough review of contemporary air suspension systems on the market for passenger cars. The evolution of suspension structures and control methodologies are briefly discussed. The layout of air suspension systems is introduced in detail, with each component receiving a comprehensive description and analysis. The open-loop and closed-loop arrangements are explained. Various types of air springs are discussed and compared. The sensory system, special working conditions, and failure analysis are also elaborated. In the case studies, some example models are listed to show a complete guide of how air suspension is implemented on passenger cars, which includes functionalities, air spring configurations, control methods, signal flow, service modes, and diagnostic messages. The major sources are OEMs’ official websites and previously released documents, such as user manuals and maintenance manuals, which are valid up to April 2023. Finally, the article concludes with a
Ma, ChangyeLu, YukunZhen, RanLiu, YegangPan, BingweiKhajepour, Amir
This Handbook is intended to accompany or incorporate AS5643, AS5643/1, AS5657, AS5706, and ARD5708. In addition, full understanding of this Handbook also requires knowledge of IEEE-1394-1995, IEEE-1394a, and IEEE-1394b standards. This Handbook contains detailed explanations and architecture analysis on AS5643, bus timing and scheduling considerations, system redundancy design considerations, suggestions on AS5643-based system configurations, cable selection guidance, and lessons learned on failure modes.
AS-1A Avionic Networks Committee
Composite sandwich beams are widely favored for their high strength-to-weight ratio, so understanding their vibration characteristics is important for optimizing designs in critical industries. This study investigates, through experimental and statistical analyses, the impact of core geometry on the vibration characteristics of epoxy/carbon fiber composite sandwich beams featuring sinusoidal and trapezoidal cores. Modal tests were conducted to determine natural frequencies, damping ratios, and mode shapes. The height and angle of the cores were treated as key independent factors influencing the beams’ vibration characteristics. In both of the cores the damping ratio values increased about 25% and 35% with increasing the height and angle of the sinusoidal and trapezoidal cores, respectively. Additionally, response surface methodology (RSM) was used for statistical analysis of these input parameters’ effects on damping properties, and the optimal values of core’s geometries were
Alwan, Majeed A.Abbood, Ahmed Sh.Farhan, Arkan J.Azadi, Reza
The escalating weight of main battle tanks (MBTs) has compelled designers to innovate with Ultra-high hard armor (UHA) steel against the current generation rolled homogenous armor (RHA). This study delves into investigating the experimental and numerical ballistic performance of 15 mm–thick UHA steel and 15 mm–thick RHA steel against a 7.62 mm armor-piercing (AP) small-arm projectile. Finite element (FE) simulations were executed using ANSYS software, incorporating the Johnsons Cook model and shock Rankine–Hugoniot equations. The outcomes highlight that the UHA steel arrests the projectile’s advancement at a depth of penetration (DoP) of 3 mm, where the mode of failure is projectile break-up with cleavage failure. Conversely, the RHA base metal demonstrates perforation accompanied by ductile hole growth as the mode of failure. This perforation is attributed to plastic deformation and material extrusion, aligning well with the FE model. In the second scenario, the ballistic limit of a
Naveen Kumar, SubramaniBalasubramanian, V.Malarvizhi, S.Sonar, TusharHafeezur Rahman, A.Balaguru, V.
Wind noise is an important indicator for evaluating cabin comfort, and it is essential to accurately predict the wind noise inside the vehicle. In the early stage of automotive design, since the geometry and properties of the sealing strip are often unknown, the contribution of the sealing strip to the wind noise is often directly ignored, which makes the wind noise obtained through simulation in the pre-design stage to be lower than the real value. To investigate the effect of each seal on wind noise, an SUV model was used to simulate the cases of not adding body seals, adding window seals, and further adding door seals, respectively. The contribution of each seal to wind noise was obtained and verified by comparing it with the test results. The influence of the cavity formed at the door seal was also addressed. In the simulations, a CFD solver based on the lattice Boltzmann method (LBM) was used to solve the external flow field, and the noise transmitted into the interior of the
Zhang, YingchaoHe, TengshengWang, YuqiNiu, JiqiangZhang, ZheShen, ChunZhang, Chengchun
The study aims to evaluate the transient failure behavior of welding joints that are exposed to sudden tensile loading. The Mohr–Coulomb criterion’s fundamental theories are examined and evaluated. The failure function of Mohr’s envelope is first expanded into a polynomial in terms of the stress components (σp , τxy ) on the failure region up to the third order. Using ANSYS software, the transient failure response of welding joints was simulated. The Runge–Kutta fourth-order computational technique was employed to perform numerical analysis on transient failure response. Python software is used to develop a computer code for the time-dependent failure response of welding joints. The welded joint specimen is tested with the help of a UTM machine. The analytical results are compared with experimental results. A fractography study was carried out on the welded joint of the failure surface. In this context, the main focus is on SEM and EDS methods to determine the exact type of failure
Chavan, ShivajiRaut, D. N.
Modern aircraft, ships, and offshore structures are increasingly constructed using fiber-reinforced composite materials. However, when subjected to lightning strikes, these materials can suffer significant structural and functional damage due to their electrical and thermal properties. This study aims to develop a novel finite element (FE) model to minimize the error in estimating the thermal damage caused during lightning strikes. This will aid in design and optimization of lightning protection systems. The developed model introduces a simplified numerical approach to model the lightning arc interaction with CFRP laminate. The existing FE model includes idealized loading conditions, leading to high error in estimation of severe damage area and in-depth damage. The proposed methodology incorporates a more realistic lightning-induced loading pattern to improve accuracy. Several cases are analyzed using available FE methods and compared to the proposed model (case 6) to evaluate the
Sontakkey, AkshayKotambkar, MangeshKaware, Kiran
It is widely known that with decreasing oil reserves on a global scale there is a need for alternative energy sources. Therefore, the introduction of various alternative fuels is of utmost importance. One way of producing alternative fuels is the Thermo-catalytic Reforming (TCR) process which was developed by the Fraunhofer-Institute for Environmental, Safety and Energy Technology (UMSICHT). For an application in conventional diesel engines, however, it is important to investigate the spray behavior of such TCR Diesel fuels in comparison to conventional Diesel fuels under engine-like operating conditions. Two different batches of TCR Diesel were compared with conventional Diesel fuels. The results show batch-dependent significant differences in the penetration length of liquid and vapor as well as in the spray area, which gives clear indications of altered mixture formation quality. Furthermore, ignition timing and ignition location were evaluated for reactive conditions using OH
Seeger, JanTaschek, MarcoApfelbacher, AndreasStrauß, LukasRieß, SebastianWensing, Michael
The arc welding process is essential for motorcycle frames, which are difficult to form in one piece because of their complex shapes, because a single frame has dozens of joints. Many of the damaged parts of the frames under development are from welds. Predicting the strength of welds with high reliability is important to ensure that development proceeds without any rework. In developing frames, CAE is utilized to build up strength before prototyping. Detailed weld shapes are not applicable to FE models of frames because weld shapes vary widely depending on welding conditions. Even if CAE is performed on such an FE model and the evaluation criteria are satisfied, the model may fail in the actual vehicle, possibly due to the difference between CAE and actual weld bead geometry. Therefore, we decided to study the extent to which the stresses in the joint vary with the variation of the weld bead geometry. Morphing, a FE modeling method and design of experiment method, was utilized to
Hada, YusukeSugita, Hisayuki
The relation between the multiple auto-ignition in the premixed charge with fuel concentration distribution and associated pressure wave are numerically investigated. This study assumes that the auto-ignition phenomenon in the end-gas of PCCI combustion, a next-generation combustion method which is expected to achieve both low fuel consumption and low emissions at a high level. Detailed numerical analysis considering the elementary chemical reactions of the compressible reacting fluid flow described in the one-dimensional coordinate system with high spatial and time resolution was performed to clarify the detailed phenomena of the onset of the multiple auto-ignition and the pressure wave propagation in the gas.
Iizumi, KotaYoshida, Kenji
Multiple-ion-probe method consists of multiple ion probes placed on the combustion chamber wall, where each individual ion probe detects flame contact and records the time of contact. From the recorded data, it is also possible to indirectly visualize the inside of the combustion chamber, for example, as a motion animation of moving flame front. In this study, a thirty-two ion probes were used to record flames propagating in a two-stroke gasoline engine. The experiment recorded the combustion state in the engine for about 3 seconds under full load at about 6500 rpm, and about 300 cycles were recorded in one experiment. Twelve experiments were conducted under the same experimental conditions, and a total of 4,164 cycles of signal data were obtained in the twelve experiments. Two types of analysis were performed on this data: statistical analysis and machine learning analysis using a linear regression model. Statistical analysis calculated the average flame detection time and standard
Yatsufusa, TomoakiOkahira, TakehiroNagashige, Kohei
Horizontal water-cooled diesel engines are single-cylinder engines equipped with all the necessary components for operation such as a fuel tank and a radiator. Due to their versatility, there are used in a wide range of applications in Asia, Africa, South America, etc. It is necessary to comply with strengthened emissions regulations year by year in countries where environmental awareness is increasing such as China, India, etc. We have developed a new compact and high-power 13.4kW(18HP) engine which meets these needs. We realized a high-power density by using our unique expertise to maintain an engine size and increase a displacement. In addition, by optimizing a layout of crankcase ribs through structural analysis, we have achieved a maximum bore and “Reduction of the weight of the crankcase and lubricating oil consumption (LOC), and reduction of friction with narrow-width low-tangential load piston rings”. Furthermore, by designing an intake port using 3D CFD, we have optimized a
Shiomi, KentaHosoya, RyosukeKomai, YoshinobuTakashima, YusukeKitamura, TakahiroFujiwara, TsukasaSuematsu, Kosuke
Flex fuel vehicles (FFV) can operate effectively from E5 (Gasoline 95%, ethanol 5%) fuel to E100 (Gasoline 0%, ethanol 100%) fuel. It is necessary to meet the performance, drivability, emission targets and regulatory requirements irrespective of fuel mixture combination. This research work focuses on optimizing the combustion efficiency and conversion efficiency of catalytic converter of a spark-ignited less than 200 cc engine for FFV using Taguchi methods robust optimization technique. The study employs an eight-step robust optimization approach to simultaneously minimize engine out emissions and maximize catalytic converter efficiency. Six control factors including type of fuel, catalyst heating rpm, lambda (excess-air ratio), injection end angle, lambda controller delay, and ignition timing are optimized. Four noise factors like compression ratio, clearance volume, catalyst noble metal loading, and catalyst aging are also considered. Through approximately 100 physical experiments on
Vaidyanathan, BalajiArunkumar, PraveenkumarShunmugasundaram, PalaniMurugesan, ManickamJayajothijohnson, Vedhanayagam
There are many riders who drive motorcycles on winding mountain roads and caused single motorcycle traffic accidents on curved roads by lane departure. Driving a motorcycle requires subtle balancing and maneuvering. In this study, in order to clarify the influence of lane departure caused by inadequate driving maneuvers against road alignment, the authors analyzed the required curve initial operation and driving maneuvers in curves depending on the traveling speed using a kinematics simulation for motorcycle dynamics. In addition, it was analyzed how inadequate driving maneuvers for curved roads can easily cause lane departure. As a result, it shows that the steering maneuvers and the lean of motorcycle body during the curves are highly affected by the vehicle speed, and the required maneuvers increases rapidly with increasing speed. The inadequate maneuver in the curves, especially for the lean of motorcycle body and steering torque, even by 10%, may cause failure to follow the
Kuniyuki, HiroshiTakechi, So
The use of small 2-stroke crankcase scavenged engines running on hydrogen is very attractive for low power rates, when low cost and compact dimensions are the fundamental design constraints. However, achieving optimal performance with hydrogen fuel presents challenges, including uneven air-fuel mixtures, fuel losses, and crankcase backfiring. This research focuses on a small 50cc 2-stroke loop-scavenged engine equipped with a patented Low-Pressure Direct Injection (LPDI) system, modified for hydrogen use. Experimental results demonstrate performance comparable to the gasoline counterpart, but further optimizations are needed. Consequently, CFD-3D simulations are employed to analyses the injection process and guide engine development. The numerical analysis focuses on a fixed operating condition: 6000 rpm, Wide Open Throttle (WOT), with a slightly lean mixture and injection pressure fixed at 5 bar. A numerical model of the entire engine is set up with the primary objective of improving
Caprioli, StefanoSchoegl, OliverOswald, RolandKirchberger, RolandMattarelli, EnricoRinaldini, Carlo Alberto
TOC
Tobolski, Sue
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