Refine Your Search

Topic

Author

Affiliation

Search Results

Training / Education

FEA Beyond Basics Thermal Analysis

2019-12-16
Finite Element Analysis (FEA) is a powerful and well recognized tool used in the analysis of heat transfer problems. However, FEA can only analyze solid bodies and, by necessity thermal analysis with FEA is limited to conductive heat transfer. The other two types of heat transfer: convection and radiation must by approximated by boundary conditions. Modeling all three mechanisms of heat transfer without arbitrary assumption requires a combined use of FEA and Computational Fluid Dynamics (CFD).
Training / Education

Weibull-Log Normal Analysis Workshop

2019-08-14
RMS (Reliability-Maintainability-Safety-Supportability) engineering is emerging as the newest discipline in product development due to new credible, accurate, quantitative methods. Weibull Analysis is foremost among these new tools. New and advanced Weibull techniques are a significant improvement over the original Weibull approach. This workshop, originally developed by Dr. Bob Abernethy, presents special methods developed for these data problems, such as Weibayes, with actual case studies in addition to the latest techniques in SuperSMITH® Weibull for risk forecasts with renewal and optimal component replacement.
Training / Education

FMEA for Robust Design What, Why, When and How

2019-07-29
Failure Modes and Effects Analysis (FMEA) is an integral part of product design activity applicable to any type of product or service. It is a qualitative and quantitative step-by-step approach for identifying and analyzing all actual and potential points of failure in a design, product or service. A successful team-based FMEA activity can use their collective experience with similar products to dramatically improve not only product performance but also reduce manufacturing issues at both a component and system and processing level. This web seminar introduces the five basic types of FMEAs with emphasis on constructing a Design FMEA.
Training / Education

Validating Requirements and Improving Specifications with Telematics Data

2019-06-19
Field failures cause high warranty expenses, perhaps the highest quality cost. Failures occur when new designs are introduced, existing products are sold in new markets, and product specifications don’t reflect actual product usage. Any mistake in product specifications affects the entire product development process and cascades through the supply chain. New product requirements are developed using prior requirements, rely on customer surveys, use “expert” opinion, or are the result of compromises to meet timing or management direction. The resulting requirements may be excessive or insufficient.
Training / Education

FEA Beyond Basics Nonlinear Analysis

2019-06-10
Finite Element Analysis (FEA) has been an indispensable tool for design simulation for several decades but this wide spread use has been limited to simple types of analyses. Relatively recently, more advanced analyses have given easy to use interfaces enabling design engineers to simulate problems formerly reserved for analysts. This three-session web seminar targets the FEA users who wish to explore those advanced analysis capabilities.
Technical Paper

Structural-Acoustic Modeling & Optimization of a Submarine Pressure Hull

2019-06-05
2019-01-1498
The Energy Finite Element Analysis (EFEA) has been validated in the past through comparison with test data for computing the structural vibration and the radiated noise for Naval systems in the mid to high frequency range [Vlahopoulos, Wu, Medyanik]. A main benefit of the method is that it enables fast computations for full scale models. This capability is exploited by using the EFEA for a submarine pressure hull design optimization study. A generic but representative pressure hull from [Jackson] is considered. Design variables associated with the dimensions of the king frames, the thickness of the pressure hull in the vicinity of the excitation (the latter is considered to be applied on the king frames of the machinery room), the dimensions of the frames, and the damping applied on the hull are adjusted during the optimization process in order to minimize the radiated noise in the frequency range from 1,000Hz to 16,000Hz.
Technical Paper

Machine Learning Based Technology for Reducing Engine Starting Vibration of Hybrid Vehicles

2019-06-05
2019-01-1450
Engine starting vibration of hybrid vehicle with Toyota hybrid system has variations even in the same vehicle, and a large vibration that occurs rarely may cause stress to the passengers. The phenomenon analysis based on the vibration theory and statistical analysis has been done to clarify, but the primary factor of the rare large vibration has not been clarified because the number of factors is enormous. From this background, we apply machine learning that can reproduce multivariate and complicated relationships to analysis of variation factors of engine starting vibration. Variations in magnitude of the compelling force such as motor torque for starting the engine and in-cylinder pressure of the engine and timing of these forces are considered as factors of the variations. In addition, there are also nonlinear factors such as backlash of gears as a factor of variation.
Technical Paper

Numerical Modeling of Internal Helmholtz Resonators Created by Punching Small Holes on a Thin-Walled Tube

2019-06-05
2019-01-1486
Helmholtz resonators are normally an afterthought in the design of mufflers to target a very specific low frequency, usually the fundamental firing frequency of the engine. Due to space limitations in a complex muffler design, a resonator may have to be built by punching a few small holes on a thin-walled tube to create a neck passage into a small, enclosed volume outside the tube. The short neck passage created by punching a few small holes on a thin-walled tube can pose a great challenge in numerical modeling, especially when the boundary element method (BEM) is used. In this paper, a few different BEM modeling approaches are compared to one another. These include modeling both sides of the thin-walled tube and the details of each small hole, modeling just the mid surface of the thin-walled tube but with the holes and possibly an added neck length, and modeling an equivalent perforated surface patch on the tube without any holes.
Technical Paper

Noise and Vibration Prediction and Validation for Off-Highway Vehicle Cab using Hybrid FE-SEA Methodology

2019-06-05
2019-01-1479
Operator noise is an important aspect for noise and vibration of off-highway vehicles and operator cab is critical for operator comfort. The noise level inside the cab is influenced by structural and acoustic transfer path. In this paper, we used hybrid FE-SEA approach to consider both structural and acoustic transfer path as FEM and SEA methods individually faces limitations in high and low frequencies respectively. A hybrid FE-SEA cab model was built and is used to predict the structural and acoustic transfer functions. The analysis model was built with the systematic approach with validation at each step with the laboratory test results. Structural excitations were applied at cab mount locations and accelerations across various locations on the cab are predicted and validated. For the acoustic transfer function, the cab was excited with the volume velocity source inside the cab and sound power output of various panels were calculated and compared to the test results.
Technical Paper

A New Method for Mid- to High-Frequency Vibration Analyses of Beam Structures

2019-06-05
2019-01-1535
Vibration analyses of complex flexible structures in mid- to high-frequency regions have important applications in auto, aerospace and ship engineering, as well as high-tech developments. In this paper, a new method is proposed for mid- and high-frequency vibration analysis of flexible beam structures. In this method, the vibration of a multi-body beam structure is modeled by an augmented formulation of the Distributed Transfer Function Method (DTFM). The formulation does not rely on discretization, treats all the beam members and different types of connection and boundary conditions systematically, and does not need to change formulas of calculation when the excitation frequency varies from low to high. Unlike conventional methods, the DTFM-based analysis does not require the knowledge of coupling loss factors and energy transmission coefficients.
Technical Paper

Comparison between Finite Element and Hybrid Finite Element Results to Test Data for the Vibration of a Production Car Body

2019-06-05
2019-01-1530
The Hybrid Finite Element Analysis (Hybrid FEA) method is based on combining conventional Finite Element Analysis (FEA) with analytical solutions and energy methods for mid-frequency computations. The method is appropriate for computing the vibration of structures which are comprised by stiff load bearing components and flexible panels attached to them; and for considering structure-borne loadings with the excitations applied on the load bearing members. In such situations, the difficulty in using conventional FEA at higher frequencies originates from requiring a very large number of elements in order to capture the flexible wavelength of the panel members which are present in a structure. In the Hybrid FEA the conventional FEA model is modified by de-activating the bending behavior of the flexible panels in the FEA computations and introducing instead a large number of dynamic impedance elements for representing the omitted bending behavior of the panels.
Technical Paper

Fatigue Life of Electronic Power Steering Control Unit (EPCU) under Mechanical Vibration loads.

2019-06-05
2019-01-1536
In current scenario, we have challenges in vibration testing on the electronics product considering the cost of testing, time taken for each prototype, pre-conditions and environment effects. Having said this, we have made technical advancement with the use of technology through finite element analysis (FEA) and computer methods. We had a challenging problem for Electronic Power Steering Control Unit (EPCU) to finalize the designs for harmonic, transient and random vibration loads at operating temperature’s (-30C; 120C) in ±X, ±Y and ±Z directions with respect to car co-ordinate systems as per the test requirements. To solve this complex problem, we proposed finite element analysis and computer methods to finalize the EPCU design where more than 40parts to be validated on the PCB during functional conditions. To start with, we understood the product qualification through test requirement document for the EPCU under mechanical vibrations loads.
Technical Paper

Modeling and Validation for the Hysteretic Behavior of an Automatic Belt Tensioner

2019-06-05
2019-01-1546
An automatic tensioner used in an engine front end accessory drive system (EFEADS) is taken as a study example in this paper. The output torque of the tensioner, which consists of the spring torque caused by a torsional spring, the damping torque caused by damping parts, and the frictional torques caused by a bushing and a rotational arm of tensioner, is analyzed by a mathematic analysis method and a finite element method. And the calculation and simulation are validated by a torque measurement versus angular displacement of a tensioner arm. The output torques of the tensioner under a loading and an unloading process are described by a bilinear hysteretic model, and are written as a function with a damping ratio. The rule of the action for the damping parts is investigated based on the simulation and a durability test of the tensioner. A finite element method for the tensioner without damping part is established.
Technical Paper

Method development for half shaft joint characterization to predict and evaluate its influence on low idle vibration in vehicle.

2019-06-05
2019-01-1558
Method development for half shaft joint characterization to predict and evaluate its influence on low idle vibration in vehicle. Author: Prasad Vesikar, Saeed Siavoshani, Siemens PLM Yuan Wei, FCA LLC In conventional IC engine powered vehicles, engine low idle vibrations of vehicle between 20 to 50Hz range is very common NVH issue. Engine excitations pass through mounts and half shafts to body structure. Half shaft designs are observed to be major influencing factor in managing these low idle vehicle vibrations. Half shaft’s dynamic characteristics are mainly dependent upon the universal joints design in the shaft. To evaluate the half shaft designs for its influence on the low idle vibration in early phase of vehicle program, predictive model of shaft is required to be generated. The shafts at low idle engine running condition are at specific pre load and shafts needs to be characterized under that preload to use in the full vehicle predictive modeling.
Technical Paper

Development of an Analytical Method for Rear Differential Gear Whine Noise utilizing Principal Component Contribution by OTPA and CAE

2019-06-05
2019-01-1555
Due to the global warming concern, CO2 emission regulations have been reinforced in most countries and electrification of automobiles has accelerated. Since the engine noise will be largely reduced, the improvements of gear whine noise becomes more important. But gear whine noise mechanism is complicated by involving many parts and transmitting paths to the cabin. Operational Transfer Path Analysis (OTPA) is one of the TPA methods to determine the main path and contributing part using only the operational data. However, in cases which many reference points are set on the same frame or body, the contribution becomes similar by high correlation among the reference data set and finding out the main transfer part becomes difficult. The contribution of principal component (PC) which is obtained from the correlated reference signals, instead of calculating the contribution from each reference point by modifying the OTPA process, has been utilized.
Technical Paper

Early Research on Additively Manufactured Sound Absorbers

2019-06-05
2019-01-1576
Additive manufacturing is slowly changing how components are developed and manufactured. As the technology evolves, it is anticipated that industry will begin 3D printing sound absorbers. In many cases, these are components that may be difficult to manufacture in another way. Several designs were 3D printed and positioned in an impedance tube for testing. Absorbers including long perforations, lightweight panels, and Helmholtz resonators with corkscrew configured necks are considered. Simulation is performed using plane wave methods and acoustic finite element analysis.
Technical Paper

Dynamic optimization of driving axle hypoid gears based on tooth contact characteristics control

2019-06-05
2019-01-1563
Hypoid gear is widely applied on automotive axle to transmit movement and power between crossed axle, and its meshing transmission has a significant influence on driving system noise of complete vehicle. Therefore, the drive noise of main hypoid gear pair at drive axle should be strictly controlled to reduce the complete vehicle noise. Meshing internal excitation of hypoid gear is a main source of vibration noise, closely connected with geometrical shape and meshing status. There is no comprehensive analysis on the impact of various contact patterns on vibration noise in previous studies. Therefore, the accurate control method of contact characteristics of hypoid gears is studied in this paper.
Technical Paper

Vibroacoustic model’s likelihood computation based on a statistical reduction of random FRF matrices

2019-06-05
2019-01-1593
The likelihood appears as the natural tool to perform such comparisons as soon as the probability of a given result may be estimated. Vibroacoustic analysis mainly relies on complex matrix-valued Frequency Response Functions that can be easily measured and computed. The likelihood of such complex and frequency dependent matrices is investigated. A two stage statistical reduction, based on Independant Components Analysis, is proposed in order to separate statisticaly independent components with random complex amplitudes. Their probability may be computed independently from one to another one. The joint probability density fonction of the real part and of the imaginary part of each independent complex-valued random variables is estimated using a nonparametric stochastic model of model uncertainties implemented in MSC/NASTRAN and the Monte Carlo simulation method as a stochastic solver.
Technical Paper

The Identification of Minimum Weight Sound Packages that Meet Specified Vehicle Interior Sound Pressure Levels

2019-06-05
2019-01-1504
A vehicle’s fuel mileage is directly related to its CO2 emissions, which have a negative impact on the environment. This negative vehicle attribute can, of course, be mitigated by increasing the vehicle’s fuel mileage beyond current levels: the reduction of vehicle weight is one of the options automobile manufacturers can employ to meet that goal. Similarly, an electric vehicles range can be increased by reducing the vehicle’s weight. Therefore, the minimization of the weight of vehicle sound packages while maintaining their acoustical performance has a positive impact on the environment as well as on vehicle efficiency. In this research, a simple model of a vehicle front-of-dash sound package which consists of a limp porous layer placed in series with a flexible microperforated panel is considered.
Training / Education

Vibration Analysis Using Finite Element Analysis (FEA)

2019-05-29
Finite Element Analysis (FEA) has been used by engineers as a design tool in new product development since the early 1990's. Until recently, most FEA applications have been limited to static analysis due to the cost and complexity of advanced types of analyses. Progress in the commercial FEA software and in computing hardware has now made it practical to use advanced types as an everyday design tool of design engineers. In addition, competitive pressures and quality requirements demand a more in-depth understanding of product behavior under real life loading conditions.
X