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Viewing 1 to 30 of 14662
2015-09-29
Technical Paper
2015-01-2866
Saeil Jeon, Stacey Spencer, Paul Joiner
Lightweight solution is one of the keywords that we see every day. Developing smart, light and durable materials is one focal area that is inevitable to be done in the ground transportation sector. Another angle to look for is the protection and beautification of the substrate finish where surface treatment technology stands out. Combining both aspects is crucial in the industry for customer satisfaction. Recycled carbon fibers are used to form the reinforcement in the composite side, where they are infused or mixed with the matrix materials either in SMC (Sheet Mould Compound) or BMC (Bulk Mould Compound) format, depending upon the application. Glass fibers are usually used for the practical application, however considering further weight cut on the component, carbon fibers cannot be overlooked for their superior mechanical properties. However, due to the cost of carbon fibers many times the application may be over-designed.
2015-09-29
Technical Paper
2015-01-2871
Mounika Katragadda, Kalyan Deepak Kolla, Venkata Suresh Yaparala
Fatigue that is induced due to vibration is known as vibration induced fatigue. There are two approaches to evaluate this, viz., time & frequency domain. A straight forward and widely used method is rainflow counting technique in time domain. This counting algorithm is readily available and apart from the time history, it needs only one variable input (number of stress ranges). In case of longer time histories, time domain approach may consume lot of time and resource, which shifts our interest towards frequency domain methods. In frequency domain, Dirlik's method is proven to be robust and gives closer results to time domain. Since Dirlik's approach is probabilistic, there are different variables (such as stress ranges, scaling factor for RMS value to predict maximum stress etc.) to be considered for cumulative fatigue damage evaluation.
2015-09-29
Technical Paper
2015-01-2758
Zhigang Wei, Robert Rebandt, Michael Start, Litang Gao, Jason Hamilton, Limin Luo
Bench testing is commonly used to construct fatigue design curves, which are used for the durability and reliability assessment of engineering components subjected to cyclic loading. Several criteria, such as R90C90 and R99C50, are widely used in automotive industry to construct fatigue design curves for a typical testing sample allocation, i.e. two stress/load levels and 6 data points at each stress/load levels. In order to reduce the test sample size and associated testing cost, recently, a Bayesian statistics based design curve construction method has been successfully developed. The Bayesian method is based on a large amount of reliable historical fatigue test data, the associated probabilistic distributions of the mean and standard deviation of the failure cycles, and an advanced acceptance-rejection resampling algorithm.
2015-09-29
Technical Paper
2015-01-2759
Zhigang Wei, Limin Luo, Shengbin Lin, Litang Gao, Fulun Yang
The linear damage accumulation models based on Miner’s rule are widely used for fatigue damage assessment of vehicle components and systems. However, the uncertainty nature of the damage accumulation process is not considered in most of the applications, in others words, the methods themselves are deterministic in nature. In engineering design and validation, understanding the lower bound, upper bound of damage status in addition to mean behavior will be beneficial in risk and safety assessment, and these goals cannot be achieved without the probabilistic concepts and tools. This study presents a general damage assessment approach, which consists of two key parts: (1) an empirical probabilistic distribution obtained by fitting the fatigue failure data at various stress range levels; and (2) an inverse technique, which transforms the failure distribution to the damage distribution at any applied cycle.
2015-09-29
Technical Paper
2015-01-2733
Samraj Benedicts, Vivek Seshan
This paper is a study of reaction forces and its effects on the chassis due to rear idler position. Rubber Track layouts and traction have been focus of most research work, here we study the effect of Rear Idler position on layout and chassis structure through simulated analysis. An agriculture paddy combine harvester with rubber track is considered for the purpose of this work. Firstly the complete undercarriage is modeled in 3D using Creo and exported to Pro Mechanica for simulation. The real time forces, constraints were applied and the results were correlated to actual field results. The simulations were optimized through several iterations to match the field test results. The simulation and field test results show good agreement to the forces and constrains applied for simulation. Secondly the model was simplified for relative analysis and simulated for different rear idler positions with alternate tensioning methods.
2015-09-29
Technical Paper
2015-01-2728
Paul C. Cain
OEM benefit: Vehicle manufacturers desire continuous feedback in monitoring key safety sub-assemblies. In this application, engineers are calculating the remaining brake pad life by monitoring the current thickness of the brake pad friction material. This information is used in scheduling preventative maintenance activities and avoiding safety incidents. Unplanned machine down time and field repair costs in earthmoving equipment is cost prohibitive. This technology allows OEM's to have high confidence, continuous feedback on this critical vehicle safety feature avoiding expensive, unplanned repairs and improving field "up time" performance. Application challenge: Developing a reliable linear position sensor that is suitable for continuous monitoring of brake pad material thickness in a high pressure, high temperature, high vibration and contaminated environments typical of large construction (earthmoving) vehicles.
2015-09-27
Technical Paper
2015-01-2660
Meechai Sriwiboon, Nipon Tiempan, Kritsana kaewlob, Seong Rhee
From a previous investigation (SAE paper numer :2014-01-2482), brake squeal was found to be related to disc wear, but not on pad wear or coefficient of friction. To further validate the disc wear – squeal correlation, a variety of formulations of No-Copper, Low-Copper and High-Copper disc pads have been made to investigate friction, pad wear, disc wear, wheel dust and brake squeal. It is found that disc wear measured after the SAE J2522 (AK Master) at the burnish cycle is closely related to brake wheel dust formation and squeal, and that there is a critical disc wear rate of approximately 0.6 g, below which wheel dust and brake squeal are minimal. It is also found that there is no correlation between brake squeal and in-stop friction coefficient or its variation at the burnish cycle of SAE J2522 (AK Master)
2015-09-27
Technical Paper
2015-01-2663
Pavlina Peikertova, Peter Filip
Automotive friction composites for brake linings are complex materials typically consisting of more than 10 different components. Some of the raw materials used by manufacturers or compounds created during the friction process might be potentially hazardous and may cause various adverse effects. Different fraction types of the brake wear debris can be released during braking: i) the airborne and ii) the nonairborne fraction. Due to the small size and minimum gravitational action, the airborne particles could be spread for long distances from a source and typically remain suspended in the air for long periods of time. Our previous research demonstrated that this fraction contains considerable amounts of different nanoparticulates. On the other hand, the emitted nonairborne fraction typically settles on vehicle/brake hardware surfaces and in the vicinity of roads.
2015-09-27
Technical Paper
2015-01-2666
Scott Lambert
The Global Brake Safety Council sees an increase in disc brake pads that are prematurely replaced before the end of the friction lining life cycle, due to: Rust related issues such as separation of friction lining from the disc brake shoe Fluctuation in critical dimensions A leading cause for both issues is the use of mill scale steel, or ‘black steel’ (non-pickled and oiled). In the North American aftermarket, as there are little or no steel specifications for disc brake shoes, black steel is increasingly used. GBSC conducted research of discarded disc brake pads from job-shops and engaged in discussions with metallurgists, major pad manufacturers and OE brake foundation engineers to identify root causes of premature pad replacement and the effects of black steel used for disc brake shoe manufacturing. Mill scale is embedded in and around the bond line of the friction lining and the disc brake shoe, causing a weaker bond, susceptible to rust jacking.
2015-09-27
Technical Paper
2015-01-2661
Amir Reza Daei, Nima Davoudzadeh, Peter Filip
Brake linings have complex microstructure and consist of different components. Fast growing automotive industry requires new brake lining materials to be developed at considerably shorter time periods. The purpose of this research was to generate the knowledge for optimizing of brake friction materials formula with mathematical methods which can result in minimizing the number of experiments/test, saving development time and costs with optimal friction performance of brakes. A combination of processing methods, raw materials and testing supported with the Artificial Neural Network allowed achieving excellent results in a very short time period. Friction performance and wear data from a series of FAST and full scale dynamometer tests, information about the process applied, and relevant data characterizing the friction layers developed for particular performance characteristics were used to train an artificial neural network, which was used to optimize the formulations.
2015-09-27
Technical Paper
2015-01-2664
Georg Ostermeyer, Joshua Merlis
EFFECTIVE SIMULATION OF THE BOUNDARY LAYER OF AN ENTIRE BRAKE PAD 1Ostermeyer, Gerog-Peter; 1Merlis, Joshua* 1TU Braunschweig, Institute of Dynamics and Vibrations, Germany KEYWORDS – Patch Dynamics, Cellular Automata, Boundary Layer, Coefficient of Friction, Simulation ABSTRACT The dynamic friction behavior of automotive brakes is generated by the boundary layer dynamics between pad and disk [1]. A key component of the Friction Interface is the influence of mesoscopic surface contact structures known as patches, upon which the friction power is concentrated, and whose sizes vary with time. Through this dynamic process, time and load history-dependent effects come about, which cause, for example, the brake moment behavior commonly observed in an AK-Master test. In recent years, several simulation tools have been developed in order to predict the complex friction behavior caused by the patch dynamics in the friction boundary layer.
2015-09-27
Technical Paper
2015-01-2665
Mattia Alemani, Oleksii Nosko, Ibrahim Metinoz, Ulf Olofsson
In the present study we investigate the emission of airborne wear particles from friction material / cast iron pairs used in car brakes, paying a special attention to the temperature effect. 5 low-metallic materials, which include phenolic resin as binder and differ in reinforcements and abrasives, and 1 non-asbestos organic material are tested by use of a pin-on-disc machine. The machine is placed in an environmental chamber which allows collecting airborne particles generated inside it avoiding external sources influence. The concentration and distribution of airborne particles with characteristic size from 0.0056 to 10 µm are measured by a fast mobility particle sizer (FMPS 3091) and an optical particle sizer (OPS 3330). An electric low-pressure impactor (ELPI+ 2E10-10) is used for collecting particles with 0.006–10 µm aerodynamic diameter. The temperature is measured in the disc by a sliding thermocouple.
2015-09-27
Technical Paper
2015-01-2678
Diego Adolfo Santamaria Razo, Johan Decrock, Ann Opsommer, Maarten Fabré, Fernao Persoon
Friction performance is the consequence of the interaction between rotor and friction material surfaces. In order to stop the car, kinetic energy has to be transformed into heat, plastic deformations, chemical reactions and wear debris (1). The latest generates the formation of the so called third body layer and its initiation, growth and degradation will generate the actual friction coefficient and wear (2). Third body layer is composed by a semi continuous layer formed by primary and secondary plateaus (3) and its chemical composition depends upon the combination of compounds present in the friction material formulation, rotor chemical composition and quality, environmental conditions and testing procedures (2). Nevertheless some raw materials seem to promote third body layer formation more than others. The main chemical composition of the plateaus are iron oxide –probably coming from the rotor- copper, carbon, silicon and calcium (3).
2015-09-27
Technical Paper
2015-01-2683
Sarah Chen, Steve Hoxie
Developing a quiet brake system has been a constant task for OEM as well as their brake suppliers. Squeal problems may taint the image of a car manufacturer and cause substantial revenue loss from warranty claims despite the fact that the brake remains fully functional and safe. As a major component in the brake system, the rotor plays significant role in brake noise performance. Because of the cost and damping property advantages, gray iron is still the most widely used material for brake rotor application. When pads/rotor coupling is looked at to minimize noise issues, however, most efforts have been on pads and insulators. Rotor specifications are rather general and the component is typically accepted based on grades defined by mechanical property minimum (mostly in G3000 SAE J431).
2015-09-27
Technical Paper
2015-01-2684
Seongjoo Lee, ShinWook Kim, ShinWan Kim, Seong Rhee
A correlation between brake squeal and disc wear was reported previously. This investigation was undertaken to confirm the correlation and to characterize the disc wear particles transferred to the sliding surface of the NAO pad. It is found that the iron distribution on the pad is very non-uniform; at some locations, the iron concentration reaches the level of Low Steel Lomets (15-20wt%); and squealing brakes exhibit increased amounts of transferred disc wear particles on the pad surface. These transferred particles are found as small and flattened thin metallic sheets, which are different from relatively large “metal pick-up” pieces.
2015-09-27
Technical Paper
2015-01-2685
Diego Masotti, Patric Neis, Ney Ferreira, Kássio Gomes, Jean Poletto, Luciano Matozo
The present work presents evaluation of the sliding surface morphology of brake pads during stick-slip process. For doing that, a brake friction material was subjected to slide against a brake disc under conditions favorable to produce stick-slip phenomenon. The experiments were conducted in a laboratory-scale tribometer, which was especially designed to test brake pads used in vehicle. Optical microscope images of the material’s surface were obtained at different stages of the braking test. These images were post-processed in appropriate computational software and by means of the segmentation technique the real contact area, size and amount of contact plateaus related to the brake pad surface were estimated. Coefficient of friction resulting from the tests was measured and it is also discussed throughout this paper.
2015-09-27
Technical Paper
2015-01-2689
Katsuhiro Uchiyama, Yuji Shishido
Last year we presented the FEA simulation of  “spring - mass (Pad’s shape) model” from stick-slip phenomenon for improvement of creep groan. Creep groan is one of representative groan noise on automobile brake system.    As a result of parameter study with various pad shape (chamfer, slot, etc.…), we showed that brake pad with radial slot angle has a range which increases creep groan performance.   This year we would like to present our study for advantageous direction for reduction of creep groan which will focus on friction material Mu vs. Velocity (M-V) property, friction material physical properties and relative velocity between brake pads and rotor by advanced brake assembly FEM model which considers torsional stiffness of suspension.
2015-09-27
Technical Paper
2015-01-2675
Erik Tobin, David Bortz, Tod Policandriotes
This paper describes test results from a new, copper-free para-aramid needlefelt composite friction material enhanced with nanoparticles. Kevlar felt-reinforced polyimide, enhanced with nanoparticles, exhibit a higher coefficient of friction than similar friction materials without nanoparticles but retain the low wear rate exhibited by those materials during full scale dynamometer testing, using the J2430 test. The threshold nanoparticle content to produce appreciable friction coefficient gains was determined. At the content levels investigated, the rotor wear was virtually undetectable while wear rate was comparable with those materials without nanoparticles. Agglomeration and distribution of nanoparticles was investigated as it pertains to friction performance and wear. New environmental regulations limiting copper content in friction materials will restrict the use of popular components found in conventional friction.
2015-09-27
Technical Paper
2015-01-2676
D.Lenin Singaravelu, Vijay R, Rahul M
Brake is a mechanical member used for converting kinetic energy into heat energy by friction. The friction is produced by the friction material which is in contact with matting surface. In 1989, the asbestos was banned globally due to its health hazards, led to booming of non-asbestos products. Now it is the era of making eco friendly products by using natural and its waste products, crab shell powder and palm kernel shell are one among them. Crab shell and palm kernel shell powders are produced by grinding the crab shell and palm kernel shell respectively to fine mesh and thereafter treatment with solution of chloroform and methanol (2:1) at room temperature for 1 hour to remove fat was done. In this present work, the friction composites are developed in the form of standard brake pads from crab shell powder following the weight percentage of 4,8,12 and is compensated by palm kernel shell powder with weight percentage of 12,8,4.
2015-09-27
Technical Paper
2015-01-2677
Amir Reza Daei, Diptarka Majumdar, Peter Filip
Automotive brake lining materials are complex composites consisting of numerous ingredients allowing for their optimal performance. Since regulations are increasingly limiting Cu content in brake pads and Cu exhibits extremely high thermal conductivity, graphites, being excellent heat conducting materials themselves, are often considered for use as potential Cu replacement.This paper surveys the role of two types of graphites (from Superior Graphite) with high thermal conductivity but different mechanical properties and morphology: the so-called i) purified flake graphite (PFG) and the ii) resilient graphitic carbon (RGC).
2015-09-27
Technical Paper
2015-01-2662
Daniela Plachá, Pavlina Peikertova, Jana Kukutschova, Poh Wah Lee PhD, Kristina Čabanová, Jiří Karas, Jana Kuchařová PhD, Peter Filip
The brake wear contribution to the environmental pollution has been extensively discussed, with major focus on asbestos and heavy metals released to the environment. Only limited attention was paid to released organic compounds generated during friction processes, although the organic and carbonaceous components are not the minor part in brake lining formulations. Friction processes in brakes are associated with relatively high temperatures and high pressures on the friction surfaces which relates to the thermal decomposition of the organic components in friction materials and to brake lining thermal fade. Thus, this study focuses on the identification of organic compounds released from a model low metallic brake material.
2015-09-27
Technical Paper
2015-01-2679
David B. Antanaitis
The proposed paper will describe how brake pad sizing (area and volume) affects fade behavior and useable life on the race track, and propose a methodology for determining the optimal brake pad size for high performance vehicles.
2015-09-27
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico, Luca Martinotto
Nature of braking friction is extremely complex and a deeper understanding of the physical mechanisms that govern the energy dissipation at the interface of friction pair is an important tool to create an even deeper knowledge of tribological behavior of friction material. Friction brakes need to transform kinetic energy into heat: a complete knowledge of thermal effects during this process in every brake component is an essential part of brake design. As referred to brake pads, the analysis of dyno testing data highlighted experimental evidences related to thermo-mechanical effects, such as the different wear resistance capabilities of material classes (NAO and Low Steel). Tribological characteristics are not constant under all testing conditions and they strongly depend on temperature being the direct consequence of kinetic energy dissipation. The aim of this work is to explain the relation between wear and energy for different type of friction materials.
2015-09-15
Technical Paper
2015-01-2608
Joshua Cemenska, Todd Rudberg, Michael Henscheid
In many existing AFP cells manual inspection of composite plies accounts for a large percentage of production time. Next generation AFP cells can require an even greater inspection burden. The industry is rapidly developing technologies to reduce inspection time and to replace manual inspection with automated solutions. Electroimpact is delivering a solution that integrates multiple technologies to combat inspection challenges. The approach integrates laser projectors, cameras, and laser profilometers in a comprehensive user interface that greatly reduces the burden on inspectors and decreases overall run time. This paper discusses the implementation of each technology and the user interface that ties the data together and presents it to the inspector.
2015-09-15
Technical Paper
2015-01-2463
Giacomo Frulla, Enrico Cestino, Piero Gili, Michele Visone, Domenico Scozzola
The problem of wing shape modification under loads in order to enhance the aircraft performance and control is continuously improving by researchers. This requirement is in contrast to the airworthiness regulations that constraint stiffness and stress of the structure in order to maintain structural integrity under operative flight conditions. The lifting surface modification is more stringent in those cases , such as UAV configurations, where the installed power is limited but the variety of operative scenario is wider than in conventional aircraft. A possible solution for adaptive wing configuration can be found in the VENTURAS Project idea. The VENTURAS Project is a funded project with the aim of improve the wind turbine efficiency by means of introducing a twisting capability for the blade sections according to the best situation in any wind condition. The blade structure is assumed divided in two parts: 1) internal supporting element, 2) external deformable envelope.
2015-09-15
Technical Paper
2015-01-2514
Scott Tomchick, Joshua Elrod, Dave Eckstein, James Sample, Dan Sherick
A new, automated production method of installing Lightweight Groove Proportioned (LGP) and Hi-Lok bolts in wing panels has been implemented by Electroimpact, Inc. The system inserts LGP and Hi-Lok bolts into interference holes using a ball screw mechanical squeeze process supported by a back side rod-locked pneumatic clamp cylinder. Collars are fed and loaded onto a swage die retaining pin and swaging is performed through ball screw mechanical squeeze. Offset and straight collar locations are accommodated for 99.99% coverage of fastener diameters of 3/16", 1/4" and 5/16". Collar stripping forces are resolved using a dynamic ram inertial technique that reduces the pull on the work piece. Titanium TN nuts are fed and loaded into a socket with a retaining spring and installed on Hi-Loks with a Bosch right angle nut runner. Bolt installation and collar swage loads, as well as nut torque values are captured and logged for future reference.
2015-09-15
Technical Paper
2015-01-2607
Matthias Meyer
STAXX Compact 1700 is a new machining centre, designed for the production of carbon fibre parts, using the fibre placement process. It produces prepreg carbon fibre stacks near to net shape which need to be moulded. As today’s high volume production lacks a reliable production system that can handle carbon fibre with high efficiency and minimal material scrap, fibre placement is the only technology that reduces material scrap during the production process significantly, especially for shell shaped parts. Most of the technical applications for lightweight construction, such as in the automotive and aerospace industries are ‘shell’ type shaped parts. While textile production methods like in resin transfer moulding may cause a scrap rate of more than 50%, fibre placement would offer a total scrap rate of below 5%. Accordingly, fibre placement offers the design option to produce parts of variable wall thickness and local reinforcement.
2015-09-15
Technical Paper
2015-01-2497
George Nicholas Bullen
The introduction of composite materials onto air vehicles has complicated the traditional hole/countersink assessment criteria due its finished-part thickness variability; softer and dissimilar properties than the metallic substructure where it is mounted and attached; and the increased attention to other acceptance criteria such as fiber tear, fiber pull, and moisture propagation in the hole that degrades fastener capability. The addition of composite materials further complicates the assembly process by adding a boundary layer of liquid shim or sealant between the composite piece (usually a skin) and the substructure. Current hole inspection systems are absent the ability to assess the interior condition of the composite hole such as fiber tear, damage to the liquid shim, and debris or burrs between the multiple stacks of dissimilar material.
2015-09-15
Technical Paper
2015-01-2461
Enrico Troiani, Maria Pia Falaschetti, Sara Taddia, Alessandro Ceruti
The high number of hull losses is a main concern in UAV field, mostly due to the high costs of equipment on board. In order to control the extent and position of crash impact damage for minimizing material losses, a crashworthiness design can be helpful. On the other hand, the wide use of composite materials has recently put the accent on the lack of data about the behavior of these structures under operative loads, such as the crash conditions. An important and interesting aspect for crashworthiness is the progressive damage of the material that leads to energy absorption. Test are needed to identify the best solution in order to achieve a controlled crush of the structure, to maximize the specific energy absorption (SEA).
2015-09-15
Technical Paper
2015-01-2596
Uli Burger, Ludovic Rochat
Lightweight structures are one key issue for all future mobility concepts. Carbon fibre reinforced plastics (CFRP) play an important role in these disciplines due to their outstanding mechanical performance regarding to their weight. Therefore, CRFP structures have been widely used since decades in aerospace industry resulting in improvements in payload, fuel consumption and range. The Airbus A350, Boeing B787 in civil airplane industry as well as military products like the NH90 transport helicopter are examples of this development towards “all composite”-aircrafts with nearly all structural parts made out of composite materials. A main difference of CFRP-structures towards metallic ones is the behavior regarding damage tolerance and fatigue. For helicopter composite structures this issue is newly defined in §573 of the relevant certification specifications (CS for EU, FAR for US) valid since December 2012.
Viewing 1 to 30 of 14662