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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
2015-01-2728
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.
2015-09-29
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
2015-01-2871
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
Journal Article
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
Journal Article
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
2015-01-2765
Shannon K. Sweeney
Abstract This paper presents simple but comprehensive modeling of the loads on the rubber sandwich-type mounts that often suspend the drum(s) in vibratory compactors or asphalt rollers. The goal of the modeling is to predict the overall performance of the rubber mount system. The modeling includes calculations to 1) identify and quantify all predictable low-frequency loads on the rubber mounts during normal vehicle operations, 2) predict the steady-state high-frequency vibration response of the drum, rubber mounts, and vehicle frame during compaction operations, 3) predict the heat generation in the rubber mounts from their hysteretic damping, and 4) predict the fatigue life and life distribution of the rubber mounts. Some typical results of the modeling are provided along with some brief criteria to assess suspension performance. Other, unpredictable suspension loads are discussed but not modeled.
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
2015-01-2685
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
2015-01-2666
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
2015-01-2692
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.
2015-09-27
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
2015-01-2684
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
2015-01-2676
D. Lenin Singaravelu, R. Vijay, M. Rahul
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
2015-01-2683
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
2015-01-2675
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
Journal Article
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
Journal Article
2015-01-2662
Daniela Plachá, Pavlina Peikertova, Jana Kukutschova, Poh Wah Lee, Kristina Čabanová, Jiří Karas, Jana Kuchařová, 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
Journal Article
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
Journal Article
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
Journal Article
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
Journal Article
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
Journal Article
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)
2015-09-15
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
2015-01-2619
Karl-Otto Strömberg, Stefan Borgenvall, Mohamed Loukil, Bertrand Noharet, Carola Sterner, Magnus Lindblom, Orjan Festin
LWPT (Lightweight Production Technology) is today a well-established technology in the automotive industry. By introducing light weight fixtures manufactured from Carbon Fiber Reinforced Plastics (CFRP), new production processes have been developed in the automotive industry. This has resulted in increased productivity, reduced investment costs and increased flexibility. The next step is to introduce this technology in the aerospace industry. Aircraft components are complex and large products having small tolerance windows. Fixtures manufactured in FRP materials allow integration of health monitoring sensors directly into the structure. This means that information on displacements can be recorded both when the fixture is stationary, while work is being performed, as well as in a pulsed production line when the fixture is moving between the assembly stations.
2015-09-15
Technical Paper
2015-01-2625
Anthony Cheruet, Robert Schmitz
In the research of lightweighting solutions, the use of CFRP has dramatically increased during the last two decades to represent today about 50 percent of the materials used in the recent commercial aircrafts. However designers are still facing the challenge to accelerate the insertion of new materials for applications. One of the main challenge concerns the reduction of the material certification time which relies only on experimental procedure. Globally speaking, there is a need for a material definition and certification in a numerical form to meet platform requirement and that allows to reduce cost and development time of new material by replacing manual tests with advanced simulation. A comprehensive simulation process is then proposed and will be described. This process allows to define a complete test matrix in order to generate B-basis allowable for a material system given. Several aspects have to be considered.
2015-09-15
Technical Paper
2015-01-2490
Sylvain Guerin, Sylvain da Costa
The quality requirement for drilling operation in aerospace industry associated to the different material layers of the recent aircraft design is one of the most challenging issues for manufacturing engineers who want to design system for one-shot drilling operation. We have developed and validated in production a handheld electrical tool which is able to accurately monitor the drilling parameter and to adjust the drilling conditions to specific material in the stack-up. This “Smart Driller” achieves quality and performances equivalent to those obtained by the most advanced heavy automated drilling systems at a small portion of weight and cost.
2015-09-15
Technical Paper
2015-01-2497
George Nicholas Bullen
Abstract 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
2015-01-2496
Lucy Agyepong, Marcus Rafla, David Tomlinson, Karl-Otto Strömberg, Alan Howarth
Abstract There is the need to strive towards more advanced aircraft with the use of materials such as composites, and a desire to improve efficiency by achieving and maintaining laminar flow over a large proportion of the aircraft wing. Due to the high tolerances required to achieve laminar flow, the manufacturing processes and tooling will have to be revaluated to enable successful manufacture in a production environment. A major influence in achieving the key characteristics and tolerances is the assembly fixture. This paper details the design and manufacture of a carbon fibre based assembly fixture, required for a one-off build of an innovative leading edge wing concept. The fixture has been designed and optimised in order to make it adaptable, reconfigurable, and suitable for lifting as well as being thermally stable whilst maintaining laminar flow tolerances.
Viewing 1 to 30 of 14662