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Viewing 1 to 30 of 2620
2017-10-08
Technical Paper
2017-01-2330
Leonardo Israel Farfan-Cabrera, Ezequiel Gallardo, José Pérez-González
Abstract Flouroelastomers and silicone rubbers are commonly employed in static and dynamic seals for automotive applications. In order to prevent premature failures and leakages caused by swelling and/or changes in their mechanical properties, materials for seals are selected according to their compatibility with the environment and fluids involved in the engine operation. Thus, in particular, the use of new fuels and additives in automotive engines requires the assessment of compatibility with common sealing elastomers to prevent failures. Currently, Jatropha oil is being used as a renewable source of fuel in diesel engines for electricity production, transport or agricultural mechanization in various countries. It is used either as biodiesel or as straight vegetable oil (SVO) since it has good heating power and provide exhaust gas with almost no sulfur or aromatic polycyclic compounds. However, the compatibility of elastomers with this SVO has not been investigated yet.
2017-09-19
Technical Paper
2017-01-2149
Cameron S. Gillespie
Abstract As carbon fiber reinforced plastics (CFRP) become more integrated into the design of large single piece aircraft structures, aircraft manufacturers are demanding higher speed and efficiency in Automated Fiber Placement (AFP) deposition systems. To facilitate the manufacturing of large surface area and low contour parts (wing skins, in this case) at a high production rate, Electroimpact has developed a new AFP head consisting of 20 1.5 inch wide pre-impregnated carbon tows. The new head design has been named the ‘OH20’, short for ‘One and a Half Inch, 20 Tows’. This AFP head format creates a deposition swath over 30 inches wide when all 20 tows are active. A total of four of these AFP heads have been integrated with a quick change robotic tool changer on two high speed, high acceleration, and high accuracy moving beam gantries.
2017-09-04
Technical Paper
2017-24-0116
Ekarong Sukjit, Pansa Liplap, Somkiat Maithomklang, Weerachai Arjharn
Abstract In this study, two oxygenated fuels consisting of butanol and diethyl ether (DEE), both possess same number of carbon, hydrogen and oxygen atom but difference functional group, were blended with the waste plastic pyrolysis oil to use in a 4-cylinder direct injection diesel engine without any engine modification. In addition, the effect of castor oil addition to such fuel blends was also investigated. Four tested fuels with same oxygen content were prepared for engine test, comprising DEE16 (84% waste plastic oil blended with 16% DEE), BU16 (84% waste plastic oil blended with 16% butanol), DEE11.5BIO5 (83.5% waste plastic oil blended with 11.5% DEE and 5% castor oil) and BU11.5BIO5 (83.5% waste plastic oil blended with 11.5% butanol and 5% castor oil). The results found that the DEE addition to waste plastic oil increased more HC and smoke emissions than the butanol addition at low engine operating condition.
2017-06-26
White Paper
WP-0001
NASA has embarked on an ambitious program to integrate additive manufacturing techniques and to develop processes for the microgravity environment. The most recent example of this program is the successful launch and deployment of the first 3D printer on the International Space Station. In this one-year effort, students were required to meet a series of milestones to design, manufacture, and test their ideas in close cooperation with members of the NASA Exploration Augmentation Module (EAM) concept team.The participants in this project were tasked with thinking of new solutions using AM that would simultaneously be recyclable with minimal loss in mechanical properties but also have the capacity for high mechanical properties. Working in interdisciplinary teams, the participant teams investigated the use of recycled materials, characterization, testing, modeling, and tool development.
2017-06-05
Technical Paper
2017-01-1880
Guojian Zhou, Xiujie Tian, Keda Zhu, Wei Huang, Richard E. Wentzel, Melvyn J. Care, Kaixuan Mao, Jiu Hui Wu
Abstract A flexible rebound-type acoustic metamaterial with high sound transmission loss (STL) at low frequency is proposed, which is composed of a flexible, light-weight membrane material and a sheet material - Ethylene Vinyl Acetate Copolymer (EVA) with uneven distributed circular holes. STL was analyzed by using both computer aided engineering (CAE) calculations and experimental verifications, which depict good results in the consistency between each other. An obvious sound insulation peak exists in the low frequency band, and the STL peak mechanism is the rebound-effect of the membrane surface, which is proved through finite element analysis (FEA) under single frequency excitation. Then the variation of the STL peak is studied by changing the structure parameters and material parameters of the metamaterial, providing a method to design the metamaterial with high sound insulation in a specified frequency range.
2017-06-05
Technical Paper
2017-01-1882
Pravin P. Hujare, Anil D. Sahasrabudhe
Abstract The reduction of vibration and noise is a major requirement for performance of any vibratory system. Due to legislative pressures in terms of external pass by noise limit of vehicles and customer requirements for better noise and ride comfort in vehicle, NVH attribute has become an important parameter. Major sources for vehicle pass-by noise consist of powertrain, tire and wind. Damping treatment is important to reduce vibration and noise radiation. The passive constrained layer dampening (CLD) treatment can be used to reduce structure-borne noise of vibrating structure using viscoelastic damping material. The performance of the passive constrained layer damping treatment can further be enhanced by new segmentation technique. The concept of segmented CLD is based on edge effect. The efficiency of segmenting a constrained layer damping treatment relies on the fact that a high shear region is created in the viscoelastic layer.
2017-06-05
Journal Article
2017-01-1813
James M. Jonza, Thomas Herdtle, Jeffrey Kalish, Ronald Gerdes, Taewook Yoo, Georg Eichhorn
Abstract The aerospace industry has employed sandwich composite panels (stiff skins and lightweight cores) for over fifty years. It is a very efficient structure for rigidity per unit weight. For the automobile industry, we have developed novel thermoplastic composite panels that may be heated and shaped by compression molding or thermoforming with cycle times commensurate with automotive manufacturing line build rates. These panels are also readily recycled at the end of their service life. As vehicles become lighter to meet carbon dioxide emission targets, it becomes more challenging to maintain the same level of quietness in the vehicle interior. Panels with interconnected honeycomb cells and perforations in one skin have been developed to absorb specific noise frequencies. The absorption results from a combination and interaction of Helmholtz and quarter wave resonators.
2017-06-05
Technical Paper
2017-01-1852
Satyajeet P. Deshpande, Pranab Saha, Kerry Cone
Abstract Most of NVH related issues start from the vibration of structures where often the vibration near resonance frequencies radiates the energy in terms of sound. This phenomenon is more problematic at lower frequencies by structureborne excitation from powertrain or related components. This paper discusses a laboratory based case study where different visco-elastic materials were evaluated on a bench study and then carried on to a system level evaluation. A body panel with a glazing system was used to study both airborne and structureborne noise radiation. System level studies were carried out using experimental modal analysis to shift and tune the mode shapes of the structure using visco-elastic materials with appropriate damping properties to increase the sound transmission loss. This paper discusses the findings of the study where the mode shapes of the panel were shifted and resulted in an increase in sound transmission loss.
2017-06-05
Technical Paper
2017-01-1877
Justin Gimbal, Joy Gallagher, John Reffner
Abstract Damping materials are applied to the vehicle body during production to provide passenger comfort by reducing noise and structural vibration through energy dissipation. Noise, Vibration, and Harshness (NVH) Engineers identify critical areas of the vehicle body for material placement. Damping materials, which include liquid applied dampers, are typically applied directly on the structure, covering large areas. These film forming materials can be spray applied using automation and, after baking, result in a cured viscoelastic damping layer on the target substrate. Typical liquid applied dampers contain an aqueous dispersion of film forming polymer which functions to bind inorganic materials together in the coating and provide a composite structure that dissipates energy. Representative damping coatings were prepared from dispersions of polymers with varying viscoelastic properties and chemical compositions.
2017-06-05
Technical Paper
2017-01-1879
Pranab Saha
Abstract Traditionally, the damping performance of a visco-elastic material is measured using the Oberst bar damping test, where a steel bar is excited using a non-contacting transducer. However, in an effort to reduce the weight of the vehicles, serious effort is put in to change the body panels from steel to aluminum and composite panels in many cases. These panels cannot be excited using a non-contacting transducer, although, in some cases, a very thin steel panel (shim) is glued to the vibrating bar to introduce ferrous properties to the bar so it can be excited. In the off highway vehicles, although the panels are made of steel, they are very thick and are difficult to excite using the Oberst bar test method. This paper discusses a measurement methodology based on mechanical impedance measurements and has the potential to be a viable/alternate test method to the Oberst bar testing. In the impedance method, the test bar is mounted to a shaker at the center (Center Point method).
2017-04-11
Journal Article
2017-01-9451
Marouen Hamdi, Drew Manica, Hung-Jue Sue
Abstract Brightness, transparency, and color impact critically the aesthetics of polymeric surfaces. They can significantly change the perception of common damages such as scratch and mar. Particularly, subtle mar damage is more dependent on surface perceptual properties. In this study, we investigate the impact of these attributes on scratch and mar visibility resistance of commercialized polymeric model systems frequently used in automotive industry. Twenty subjects were involved in a psychophysical test based on pairwise comparison, and results were treated using multidimensional scaling (MDS) analysis. A tied ordinal weighted Euclidian MDS model was used to visualize the relational structures of mar perception space. Results show that scratch visibility resistance tends to decrease with dark, more transparent, and green surfaces. Mar perception was reasonably conceptualized by a two-dimensional MDS space.
2017-03-28
Technical Paper
2017-01-1741
Hyerin Choi, JunHo Song, Jae kwang Lee, Jaeyong Ko
Abstract Recently, it is one of the major problems in the automotive industry that grating is occurred form the place that more than two different materials combined. It is the most severe case that the noise generates between automobile seats and other relative parts (or within seat parts). The purpose of this research verifies and suggests the way to reduce squeak noise between two different parts through the stick-slip test which is regulated by VDA. The two materials - the seat trim cover and the plastic - were selected as major factors. We conducted the test with two different types of seat trim cover (authentic and artificial leather) and plastics (PP and ABS) with 4 levels of embossing size (0 to 3, level ‘0’ is non-embossing. Level 1 is the biggest embossing and it goes through smaller. Level 3 is the smallest embossing size). Test results were reported with 1 to 10 Risk Priority Number (RPN) which was proposed by VDA (Verband der Automotilindustrie).
2017-03-28
Technical Paper
2017-01-1731
Manida Tongroon, Amornpoth Suebwong, Mongkont Kananont, Jirasak Aunchaisri, Nuwong Chollacoop
Abstract Derived from palm Fatty Acid Methyl Ester (FAME), high quality biodiesel called H-FAME has been introduced in order to increase its percentage blended with diesel. Due to monoenen-rich FAME by partial hydrogenation process, H-FAME is superior oxidation and thermal stability. In the current study, the effects of 20 percent of high quality biodiesel blended with diesel (B20) on the compatibility of polymeric engine parts have been investigated by means of the immersion test. Pure diesel has also test as the reference. Following SAE J1748 in conjunction with ASTM D471, selected commercial engine parts such as fuel hose and tank were immersed in the test fuels. In addition, Viton fluoroelastomers, neoprene and nitrile butadiene rubber (NBR) were also soaked for comparison. Apparent percent weight increase was used to indicate the change of the engine parts after exposed to the test fuels.
2017-03-28
Technical Paper
2017-01-0489
Hyunkwon Jo, Jongsoo Kim, Jaemin Park, Heeseung Yang, Hyunmin Park
Abstract Cost reduction is an important issue in the intense competition automotive industry. Interior parts which are mainly consist of plastic have same issue. The manufacturing main processes of plastic products are injection and assemble and the cost of injection depends on injection cycle time. Therefore many studies for the reduction of injection cycle time have been implemented. However the researches based on engineer's experiences have limits so, nowadays many studies utilize CAE. In this paper, the study for the reduction of cycle time focused on injection molding design. To satisfy appearance quality with the reduction of cycle time, the design of injection molding was optimized by using CAE. The result of CAE showed many causes and effects of problems. The optimization of injection molding design improved the quality with the reduction of cycle time. Finally, the product based on CAE showed good quality and cycle time reduction in comparison with previous products.
2017-03-28
Technical Paper
2017-01-0491
Hyerin Choi, Jaeyong Ko, JunHo Song, SeungKeon Woo
Abstract Recently, it is one of a major problems in automotive industry that wrinkles on seat interior occur at detaching between seat covering and padding foam. The purpose of this research is the way to improve heat resistance and adhesion using polyurethane reactive (PUR) of thermosetting plastic material. We compose PUR that makes thin film and non-tacky characteristic on padding foam. We find optimum situation (method and amount) for leather and padding foam. Viscosity and melting temperature are adjusted to coat with amount. 25~30g/m2 are suitable on padding foam unlike traditional method to coat leather above 100g/ m2. We also verified performances of PUR lamination compared to others. As result, peel strength is strongest at 15.4N/30mm. Heat resistance is also excellent with various padding foams. Furthermore we advance an additional jig to match leather and padding foam by low tacky characteristic of PUR. This jig can increase productivity in seat manufacturing process.
2017-03-28
Technical Paper
2017-01-0490
Rodrigo Polkowski, Alper Kiziltas, Marcelo Ueki
Abstract In recent years, a special attention has been given to the environment protection, as evidenced by an increased commitment of governments and industries for a better use of energy and for reducing the levels of vehicle emissions (CO2). The use of renewable and bio-based plastics in the automotive sector is being considered as alternative solution to the conventional petroleum-based polymeric materials. In the present work, biobased polymer blends were formulated using two polyamides made from biorenewable resources. Polyamide 10,10 (PA1010) and polyamide 6,10 (PA610) were melt mixed in different compositions and the mechanical properties of the blends were investigated by tensile evaluations. The mechanical properties of the blends show intermediate values compared to the pure polymers. Significant improvements on these properties could be observed with the incorporation of PA610 in the blends.
2017-03-28
Technical Paper
2017-01-0481
Xian Jun Sun, Patricia Tibbenham, Jin Zhou, Danielle Zeng, Shiyao Huang, Li Lu, Xuming Su
Abstract Weld lines occur when melt flow fronts meet during the injection molding of plastic parts. It is important to investigate the weld line because the weld line area can induce potential failure of structural application. In this paper, a weld line factor (W-L factor) was adopted to describe the strength reduction to the ultimate strength due to the appearance of weld line. There were two engineering thermoplastics involved in this study, including one neat PP and one of talc filled PP plastics. The experimental design was used to investigate four main injection molding parameters (melt temperature, mold temperature, injection speed and packing pressure). Both the tensile bar samples with/without weld lines were molded at each process settings. The sample strength was obtained by the tensile tests under two levels of testing speed (5mm/min and 200mm/min) and testing temperatures (room temperature and -30°C).
2017-03-28
Technical Paper
2017-01-0482
Cristiano Grings Herbert, Luiz Rogério De Andrade Lima, Cristiane Gonçalves
Abstract Phthalates have been extensively used in rubbers formulation as plasticizer additive for PVC and NBR promoting processing parameters or for cost reduction. The most commonly used plasticizer in PVC compounds was di-2-ethylhexyl phthalate (DEHP) currently not recommend due toxicity. DEHP is listed as prohibited to the Global Automotive Declarable Substance List (GADSL). Phthalates alternatives are already available but the compatibility in automotive fuel system with biodiesel was not extensively understood. This aspect is important since plasticizer may migrate and change rubber properties. Tri-2-ethylhexyl trimellitate (TOTM) and di-2-ethylhexyl terephthalate (DEHT) were selected in this work as alternative additives to a rubber formulation since is not listed to GADSL and have good potential as plasticizer.
2017-03-28
Technical Paper
2017-01-0508
Gabor Kiss, Yuya Ando, Martin Schifko
Abstract Simulation tools are becoming more and more popular in the automotive industry since they can significantly reduce the costs required for development of new models. Currently there are many computational fluid dynamics (CFD) tools available on the market and becoming indispensable tools for R&D in many of the automotive applications. However there are some applications which require much effort by highly skilled engineers to prepare the model and impractical level of computation time even using a cluster computer using the conventional CFD tools due to the nature of physics and complexity of a geometry such like dip painting process. Therefore, corrosion protection engineers are striving to find an alternative solution. Another issue is that the main focus of those available CFD tools are problems occurring during the dip paint simulations and they omit problems occurring after the object dips out from the bath, such as retained water or bake drips.
2017-03-28
Technical Paper
2017-01-0503
Ahmad Waqar Tehami, Kamran Asim, Shahzad Sarwar
Abstract Fiber reinforced laminated materials are becoming popular in applications involving protection against impact loading. Laminates offer many advantages over metal plates in these applications. Laminates are normally non-ricochet, thus offering greater protection against projectiles. Laminates are also lighter in weight and less expensive as compared to the metal panels. In this study, laminated materials were fabricated from two different types of fibers which included short fibers and random fibers. Epoxy and polyester were used as the resin materials in the production of different types of laminates. Test samples were tested according to the available standards to investigate the impact toughness and ballistic resistance of these laminates. Experimental results showed that random fibers and polyester resin absorbed more energy as compared to short fibers and epoxy resin, respectively.
2017-03-28
Technical Paper
2017-01-0323
Rosa Radovanovic, Samuel J. Tomlinson
Abstract Press-in-place gasket stability is required to maintain consistent and predictive sealing compression in a sealing joint utilizing a housing groove and a mating component sealing surface. Without proper balance between height of the groove and height of the gasket, the sealing joint can be compromised. Hence, automotive engineers balance design variables with the desire to achieve long term sealability and gasket stability. The percentage of gasket out of groove was varied to study the interactions of this design control and the resultant deviation of gasket centerline to the groove centerline. Finally, an optimal percentage of gasket out of groove is recommended.
2017-03-28
Technical Paper
2017-01-0125
Marco Pizzi, Mauro Zorzetto, Alberto Barbano, Piercarlo Merlano, Luca Vercellotti
Abstract The emission reduction in gasoline and diesel engines is driving the introduction of systems implementing additives in liquid form: in particular water for injection systems in gasoline engines and urea solutions (AD-blue) in SCR (Selective Catalytic Reduction) systems in diesel engines. Owing to water and AD-Blue can freeze in the car operative temperature range, the tanks must be equipped with heaters to guarantee a sufficient amount of additives in liquid form. Currently used technologies are ceramic PTC (Positive Temperature Coefficient) elements and distributed metal resistors. Ceramic PTC based heaters concentrate all the power in small volumes. They need thermally conductive elements distributing the power over a wide area. The assembly is complex and the cost of the metal parts and related packaging technologies used to insulate the heater from the environment (water or urea) is typically high. Metal resistors are cheaper but must be controlled in current.
2017-03-28
Technical Paper
2017-01-0405
Tianqi Lv, Xingxing Feng, Peijun Xu, Yunqing Zhang
Abstract Three constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
2017-03-28
Technical Paper
2017-01-0455
Harshad Hatekar, Baskar Anthonysamy, V. Saishanker, Lakshmi Pavuluri, Gurdeep Singh Pahwa
Abstract Structural elastomer components like bushes, engine mounts are required to meet stringent and contrasting requirements of being soft for better NVH and also be durable at different loading conditions and different road conditions. Silent block bushes are such components where the loading in radial direction of bushes are high to ensure the durability of bushes at high loads, but has to be soft on torsion to ensure good NVH. These requirements present with unique challenge to optimize the leaf spring bush design, stiffness and material characteristics of the rubber. Traditionally, bushes with varying degree of stiffness are selected, manufactured and tested on vehicle and the best one is chosen depending on the requirements. However, this approach is costly, time consuming and iterative. In this study, the stiffness targets required for the bush were analysed using static and dynamic load cases using virtual simulation (MSC.ADAMS).
2017-03-28
Journal Article
2017-01-0488
Raju Gandikota
Abstract Testing elastomeric materials that undergo large strains pose challenges especially when establishing failure criteria. The failure criterion for composites and polymers based on finite elasticity published by Feng (1) requires testing under uniaxial and biaxial stretching modes. The classic inflation of a circular disk for biaxial stretch mode poses stability and safety challenges. The test can also be sensitive to end constraints resulting in failure of materials at the constraints. Biaxial stretching with a hemispherical punch is explored in this work. The biaxial stretching allows controlled and repeatable testing. It establishes a clear and reliable failure mechanism of the material at the poles. Through a combination of testing and numerical methods, the stretch ratios and its relation to failure have been established. The method greatly simplifies testing and provides reliable data for a failure criterion for elastomers in numerical modeling.
2017-03-28
Technical Paper
2017-01-0460
Erina Yasuda, Hiroki Kobayakawa, Seiji Amano, Yuto Otsuki, Tomohiro Ukai
Abstract The number of vehicles with engines using idling stop systems and hybrid systems to improve fuel consumption has recently been increasing. However, with such systems the frequent starts and stops of the engine, where the oil film between the bearings and shaft is squeezed out and direct contact between the components is more likely, can result in increased wear of the engine bearings, particularly in the main bearing. Bearings with resin overlays have been shown to display superior resistance to wear from such start-stop cycles. Moreover, cast iron shafts without quenching treatment have also been used in engines for cost reduction. Because the cast shaft has low hardness and unstable surface graphite after abrasive finishing, increase in the wear amount cannot be suppressed by conventional resin overlay in comparison with steel shaft. Therefore, the resin overlay with improved wear resistance achieved by adding hard particles was developed.
2017-03-28
Technical Paper
2017-01-0468
Raj S. Roychoudhury
Abstract A new weld design to form plastic hollow articles is conceived. Its design is T-shaped such that the joint loading under pressure is no longer in peel but in tension, vertically to the weld surface. This weld design can be easily achieved, overcoming the limitation of die lock in injection molding and by the hot plate weld design adopted for this welding. Test samples were built to evaluate the new weld design concept and hot plates designed to help perform this weld joint. Pull test on the conventional L-shaped and the new T- shaped welded samples show an improvement of about 50% weld strength for the new T-shaped weld design. Hence a weld joint stronger than the parent material, in forming plastic hollow articles, is possible.
2017-03-28
Technical Paper
2017-01-0507
Christian K. Riener, Anna-Elisabeth Raab, Gerald Luckeneder, Martin Rosner
Abstract Zinc-coatings with a substantial Magnesium content have been in use for over 30 years by now. Unlike the well-established Zn-Al-Mg coatings originating from Japan which have significant higher alloying contents applied mainly for building applications, this Zinc Magnesium Aluminum coating (ZM) is also specifically designed to meet the requirements of car manufacturers. The ZM coating introduced by voestalpine, corrender, is in the upper range of ZM-alloying compositions, which was set by VDA (German Association of the Automotive Industry) and SAE to be within 1.0 to 2.0 wt. % Mg and 1.0 to 3.0 wt. % Al. The properties of these “European” Zinc-Magnesium coatings are well comparable within this range. Compared to GI and GA ZM coatings exhibit significant advantages in the press shops with its excellent formability and reduced galling and powdering respectively which is a significant advantage for the forming of outer panels.
2017-03-28
Technical Paper
2017-01-0363
Karthik Ramaswamy, Vinay L. Virupaksha, Jeanne Polan, Biswajit Tripathy
Abstract Expanded Polypropylene (EPP) foams are most commonly used in automotive applications for pedestrian protection and to meet low speed bumper regulatory requirements. In today’s automotive world the design of vehicles is predominantly driven by Computer Aided Engineering (CAE). This makes it necessary to have a validated material model for EPP foams in order to simulate and predict performance under various loading conditions. Since most of the automotive OEMs depend on local material suppliers for their global vehicle applications it is necessary to understand the variation in mechanical properties of the EPP foams and its effect on performance predictions. In this paper, EPP foams from three suppliers across global regions are characterized to study the inter-supplier variation in mechanical properties.
2017-03-28
Technical Paper
2017-01-0332
Zhengpan Qi, Li Lu, Linh Doan, Bhavani Thota, Danielle Zeng, Xuming Su
Abstract High density polyethylene (HDPE) is widely used in automotive industry applications. When a specimen made of HDPE tested under cyclic loading, the inelastic deformation causes heat generated within the material, resulting in a temperature rise. The specimen temperature would stabilize if heat transfer from specimen surface can balance with the heat generated. Otherwise, the temperature will continue to rise, leading to a thermo assist failure. It is shown in this study that both frequencies and stress levels contribute to the temperature rise. Under service conditions, most of the automotive components experience low cyclic load frequency much less than 1 Hz. However, the frequency is usually set to a higher constant number for different stress levels in current standard fatigue life tests.
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