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Technical Paper

A Study of Lead-free Al-Zn-Si Alloy Bearing with Overlay for Recent Automotive Engines

2009-04-20
2009-01-1054
Recently, a lead-free Al-Sn-Si alloy bearing with metallic overlay has started to be used for a portion of automotive engines. This bearing has good anti-seizure and excellent running-in properties, and is an environmentally friendly alternative to the current copper-lead alloy with lead based overlay in accordance with the ELV regulation for the removal of lead from bearings. But automotive engines have been required to exhibit higher performance in order to enhance their commercial power, which tends to require the engine bearing to perform under higher temperature due to higher specific load on the bearing and higher rotational speed of the crankshaft. It is clear that the current lead-free aluminum alloy bearing is not satisfactory with respect to fatigue strength in some cases, and requires higher strength under the higher temperature conditions.
Journal Article

Design of Cellular Shear Bands of a Non-Pneumatic Tire -Investigation of Contact Pressure

2010-04-12
2010-01-0768
In an effort to build a shear band of a lunar rover wheel which operates at lunar surface temperatures (40 to 400K), the design of a metallic cellular shear band is suggested. Six representative honeycombs with aluminum alloy (7075-T6) are tailored to have a shear modulus of 6.5MPa which is a shear modulus of an elastomer by changing cell wall thickness, cell angles, cell heights and cell lengths at meso-scale. The designed cellular solids are used for a ring typed shear band of a wheel structure at macro-scale. A structural performance such as contact pressure at the outer layer of the wheel is investigated with the honeycomb shear bands when a vertical force is applied at the center of the wheel. Cellular Materials Theory (CMT) is used to obtain in-plane effective properties of a honeycomb structure at meso-scale. Finite Element Analysis (FEA) with commercial software ABAQUS is employed to investigate the structural behavior of a wheel at macro-scale.
Technical Paper

Reducing Porosity in Aluminum Lost Foam Castings Through Computer Simulation

2009-04-20
2009-01-0556
The lost foam casting (LFC) process offers unmatched versatility for producing near-net shape complex components for the automotive industry. Castings made by the LFC process can replace numerous individually-manufactured parts through part consolidation, have little or no draft, and have minimum machining stock. However, the filling behavior of lost foam castings is very different from that of open-cavity castings, so methods to reduce casting anomalies are not intuitive. Casting simulation codes have been in use for the past three decades and they are reasonably successful in predicting porosity in steel and other ferrous castings. The prediction of porosity in aluminum alloys is difficult because of long freezing ranges and lack of accurate thermo-physical property data. Also, for lost foam castings, large thermal gradients are created by slow mold filling, which further complicates porosity prediction.
Technical Paper

Effects of Cellular Shear Bands on Interaction between a Non-pneumatic Tire and Sand

2010-04-12
2010-01-0376
To facilitate the design of a non-pneumatic tire for NASA's new Moon mission, the authors used the Finite Element Method (FEM) to investigate the interaction between soil and non-pneumatic tire made of different cellular shear bands. Cellular shear bands, made of an aluminum alloy (AL7075-T6), are designed to have the same effective shear modulus of 6.5E+6 Pa, which is the shear modulus of an elastomer. The Lebanon sand of New Hampshire is used in the model. This sand has a complete set of material properties in the literature and Drucker-Prager/Cap plasticity constitutive law with hardening is employed to model the sand. The tires are treated as deformable bodies, and the authors used the penalty contact algorithm to model the tangential behavior of the contact. The friction between tire and sand is considered by using Coulomb's law. Numerical results show deformation of sand and tire.
Journal Article

Study of Bending Strength for Aluminum Reinforced with Epoxy Composite

2016-04-05
2016-01-0516
Abstract Fiber reinforced composite-metal hybrids are of great interest in automotive industry because of their excellent mechanical properties and light-weighting potential. Adhesive bonding is a preferred joining technique for manufacturing fiber reinforced composite metal hybrids. Metal surface due to the presence of process contaminants (oil, dirt, oxide layer etc.) is difficult to bond. The surface prior to adhesive application needs to be cleaned or modified using surface pretreatment methods. Especially for adhesive bonding of multimaterial joining, surface treatment is a very important step. In this paper, 7xxx series extruded aluminum alloy surface was treated using different conventional surface treatment methods and bonded with glass fiber reinforced epoxy tape/mat (FRP). The intent is to stiffen aluminum with lightweight FRP for energy absorbing part application.
Technical Paper

Design of Compact Aluminum Cylinder Head

2015-01-14
2015-26-0035
Abstract The cylinder head of a diesel engine is a multi-functional entity, decidingthe performance and emission parameters of the engine. It also acts as a structural and sealing member. It accommodates ports for gas exchange process; injectors for combustion process, cooling passages optimized for heat transfer, valve train mechanism, and lubrication circuits and in addition in our case integrated common rail fuel injection pump drive and systems. Aluminum is light weight with benefits. Combustion is direct injection subject to higher thermal and mechanical loads, it must be robust enough to withstand the high operating temperature and peak firing pressure. The design and development of effective Intake and Exhaust Ports remains critical to improve volumetric efficiency. Compactness not only helps in packaging by having optimum LBH but also in making it light.
Technical Paper

Compression and Energy Absorption of Aluminum Alloy AA6061 and AA7005 Tubes Using Experimental and Simulation Methods

2015-01-14
2015-26-0169
Abstract There is a growing need for improved conceptual vehicle designs along with alternative materials to reduce the damage to the passengers and structures in aerospace and automotive industries. The energy absorption characteristics of materials play a major role in designing a safe vehicle for transport. In this paper, compression behavior and energy absorption of aluminum alloy AA6061 and AA7005 tubes in T4 and T6 conditions are investigated by experimental and numerical methods. The AA7005 and AA6061 tubes are solution heat treated and then aged to achieve the final strength in T6 condition. Experimental compression test results have shown improved energy absorption of tubes in T6 condition compared to tubes in T4 condition. There is less variation of energy among the tested samples. The mean load is compared with the results obtained from analytical formulae. Tensile properties have been obtained from tensile tests using UTM for both AA6061 and AA7005 tubes.
Technical Paper

A New Measurement of Aluminum Alloy Edge Stretching Limit Based on Digital Image Correlation Method

2016-04-05
2016-01-0417
Abstract In Aluminum Alloy, AA, sheet metal forming, the through thickness cracking at the edge of cut out is one of the major fracture modes. In order to prevent the edge cracking in production forming process, practical edge stretch limit criteria are needed for virtual forming prediction and early stamping trial evaluations. This paper proposes new methods for determining the edge stretching limit of the sheet coupons, with and without pre-stretching, based on the Digital Image Correlation (DIC) technique. A numbers of sets of notch-shaped smaller coupons with three different pre-stretching conditions (near 5%, 10% and fractured) are cut from the prestretched large specimens. Then the notch-shaped smaller coupons are stretched by uniaxial tension up to through edge cracking observed. A dual-camera 3D-DIC system is utilized to measure both coupon face strain and thickness strain in the notch area at the same time.
Technical Paper

Fatigue Life Prediction of Friction Stir Linear Welds for Magnesium Alloys

2016-04-05
2016-01-0386
Abstract Friction stir linear welding (FSLW) is widely used in joining lightweight materials including aluminum alloys and magnesium alloys. However, fatigue life prediction method for FSLW is not well developed yet for vehicle structure applications. This paper is tried to use two different methods for the prediction of fatigue life of FSLW in vehicle structures. FSLW is represented with 2-D shell elements for the structural stress approach and is represented with TIE contact for the maximum principal stress approach in finite element (FE) models. S-N curves were developed from coupon specimen test results for both the approaches. These S-N curves were used to predict fatigue life of FSLW of a front shock tower structure that was constructed by joining AM60 to AZ31 and AM60 to AM30. The fatigue life prediction results were then correlated with test results of the front shock tower structures.
Journal Article

Crushing Analysis and Lightweight Design of Tapered Tailor Welded Hybrid Material Tubes under Oblique Impact

2016-04-05
2016-01-0407
Abstract The increasing demand for lightweight design of the whole vehicle has raised critical weight reduction targets for crash components such as front rails without deteriorating their crash performances. To this end the last few years have witnessed a huge growth in vehicle body structures featuring hybrid materials including steel and aluminum alloys. In this work, a type of tapered tailor-welded tube (TTWT) made of steel and aluminum alloy hybrid materials was proposed to maximize the specific energy absorption (SEA) and to minimize the peak crushing force (PCF) in an oblique crash scenario. The hybrid tube was found to be more robust than the single material tubes under oblique impacts using validated finite element (FE) models. Compared with the aluminum alloy tube and the steel tube, the hybrid tube can increase the SEA by 46.3% and 86.7%, respectively, under an impact angle of 30°.
Technical Paper

The Influence of Edge Quality on Edge Stretching Limit for Aluminum Alloy

2016-04-05
2016-01-0416
This paper presents the measurement and analysis of the edge stretching limit of aluminum alloy using digital image correlation. The edge stretching limit, also known as the “edge thinning limit,” is the maximum thinning strain at a point of edge failure resulting from tension; which may be predisposed by edge quality. Edge fracture is a vital failure mode in sheet metal forming, however it is very difficult to measure. A previous study enabled the measurement of edge thinning strain by using advanced digital image correlation but it did not consider how the edge quality could affect the edge stretching limit of aluminum alloy. This paper continues to measure edge thinning strain by comparing polished to unpolished AA5754, thus determining the effect edge quality has on the edge stretching limit. To enable the measurement by optical method for a very long and thin sample, a notch is used to localize where edge failure occurs.
Technical Paper

Assessment of Residual Stress in T5 Treated 319 Aluminum Alloy Engine Blocks Using Neutron Diffraction

2016-04-05
2016-01-0353
Abstract Aluminum alloys have been replacing ferrous alloys in automotive applications to reduce the weight of vehicles. The engine block is a striking example of weight reduction, and is made of Al-Si-Cu-Mg (319 type) alloys. The wear resistance in the engine block is enabled by cast iron liners, and these liners introduce tensile residual stress due to a thermo-mechanical mismatch. Typically, an artificial aging treatment effectively reduces residual stress. In this study, neutron diffraction was used to measure the residual stress profiles along the cylinder bridge of a T5 treated 319 aluminum alloy engine block. Results indicated high tensile residual stresses (200-300 MPa) in the hoop and axial orientation at depths of 50-60 mm below the head deck. The high residual stresses were likely due to a combination of minimal stress relief during artificial aging and stress development during post process cooling.
Technical Paper

The Newly Developed Components for the Fuel Cell Vehicle, Mirai

2015-04-14
2015-01-1174
Abstract Toyota Boshoku developed two completely new components for the fuel cell vehicle (FCV), Mirai. These are the fuel cell (FC) Separator, and Stack manifold. The separators are made from stamped metal plates. The anode and cathode separators sandwich the MEA(Membrane Electrode Assembly) between them. It has flow paths for the hydrogen, air and FC coolant. The Anode Separator has hydrogen flow paths on one side, and cooling liquid flow paths on the other side. The pitch used in the flow paths is very fine and it improves both the uniformity of the gas flow and of the surface pressure on the MEA. Therefore, it has contributes to improve the electric power generation performance. The FC Stack manifold is a component that attaches to the end of one side of the FC stack. It is a component that integrates end plate and pipes. The end plate is a portion of the FC stack which holds the fastening load of stack and is made of cast aluminum casting alloy.
Technical Paper

MMLV: Aluminum Cylinder Block with Bulkhead Inserts and Aluminum Alloy Connecting Rod

2015-04-14
2015-01-1238
Abstract The Multi Material Lightweight Vehicle (MMLV), developed by Magna International and Ford Motor Company, is a result of US Department of Energy project DE-EE0005574. The project demonstrated the lightweighting potential of a five-passenger sedan while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full-vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially-available materials and production processes, achieved a 364 kg (23.5%) full-vehicle mass reduction. This resulted in environmental benefits and fuel economy improvements. A significant factor in the overall MMLV mass reduction was the decrease in the powertrain system weight from 340 kg (conventional) to 267 kg (MMLV). This enabled the application of a 1.0-liter three-cylinder engine as the main powerplant. By downsizing the engine, and by implementing material changes within the engine, the weight of the dressed engine was lowered by 29 kg.
Technical Paper

Optimization of Piston Skirt Profile Design to Eliminate Scuffing and Seizure in a Water Cooled Gasoline Engine

2015-04-14
2015-01-1726
Abstract Piston is a critical component of the engine as it exposed to high inertial and thermal loads. With the advent of high performance engines, the requirement of the piston to perform in extreme conditions have become quintessential. Piston scuffing is a common engine problem where there is a significant material loss at the piston and the liner, which could drastically affect the performance and the longevity of the components. This detrimental phenomenon would occur if the piston is not properly designed taking into consideration the thermal and structural intricacies of the engine. A water-cooled gasoline engine which had significant wear pattern on its piston skirt and liner was considered for this study. The engine block was made of aluminum alloy with a cast iron sleeve acting as liner. The piston-liner system was simulated through a commercially available numerical code which could capture the piston's primary and secondary motion.
Technical Paper

Prediction of Component Failure using ‘Progressive Damage and Failure Model’ and Its Application in Automotive Wheel Design

2015-04-14
2015-01-1516
Abstract Damages (fracture) in metals are caused by material degradation due to crack initiation and growth due to fatigue or dynamic loadings. The accurate and realistic modeling of an inelastic behavior of metals is essential for the solution of various problems occurring in engineering fields. Currently, various theories and failure models are available to predict the damage initiation and the growth in metals. In this paper, the failure of aluminum alloy is studied using progressive damage and failure material model using Abaqus explicit solver. This material model has the capability to predict the damage initiation due to the ductile and shear failure. After damage initiation, the material stiffness is degraded progressively according to the specified damage evolution response. The progressive damage models allow a smooth degradation of the material stiffness, in both quasi-static and dynamic situations.
Journal Article

Simulation and Optimization of an Aluminum-Intensive Body-on-Frame Vehicle for Improved Fuel Economy and Enhanced Crashworthiness - Front Impacts

2015-04-14
2015-01-0573
Abstract Motivated by a combination of increasing consumer demand for fuel efficient vehicles, more stringent greenhouse gas, and anticipated future Corporate Average Fuel Economy (CAFE) standards, automotive manufacturers are working to innovate in all areas of vehicle design to improve fuel efficiency. In addition to improving aerodynamics, enhancing internal combustion engines and transmission technologies, and developing alternative fuel vehicles, reducing vehicle weight by using lighter materials and/or higher strength materials has been identified as one of the strategies in future vehicle development. Weight reduction in vehicle components, subsystems and systems not only reduces the energy needed to overcome inertia forces but also triggers additional mass reduction elsewhere and enables mass reduction in full vehicle levels.
Technical Paper

Comparative Corrosion Assessment of Coated Alloys for Multi-Material Lightweight Vehicle Architectures

2015-04-14
2015-01-0738
Abstract The purpose of this study was to conduct a comparative corrosion assessment of alloys and coating schemes of interest for the fabrication of multi-material lightweight vehicle architectures. Alloys considered for this application included galvanized high strength low alloy steel, aluminum alloy AA6111 and magnesium alloy ZEK100. The coating scheme considered for corrosion protection included a layered paint top-coat scheme that was applied to a pre-treated surface. The pre-treatments included an alloy-specific commercial conversion coating (CC) and a plasma electrolytic deposition (PED) process that was applied only to the ZEK100 material. The corrosion assessment of the scribed coated alloy panels was conducted after 1000 h exposure in the ASTM B117 salt fog environment. Characterization of the mode and extent of corrosion damage observed and the role played by the exposed alloy microstructure utilized both light optical microscopy and electron microscopy.
Technical Paper

A Study of Lead-Free Aluminum Alloy Bearings with Overlay for Recent Automotive Engines

2008-04-14
2008-01-0091
Recently, a Lead-free aluminum alloy bearing with available fatigue strength is partially applied for plain bearings in automotive engines as replacement of a conventional copper alloy bearing with lead based overlay, according to requirement of ELV regulation, which requires the lead removal from bearing. However, our recent investigation made clear that the aluminum alloy bearing did not have enough running-in property when operated under severe condition of thinner oil film in recent automotive engine with further higher performance. Based upon these backgrounds, a lead-free bearing was newly developed by applying overlay onto the aluminum alloy bearing for better running-in property of the bearing.
Technical Paper

The Effect of Solidification Time and Solution-Treatment Time on the Tensile Properties of a Cast 319-T7 Aluminum Alloy

2007-04-16
2007-01-1224
A study was conducted to examine the effect of solidification time and solution treatment time on the tensile properties of a 319-type aluminum alloy. Tensile samples with solidification times ranging from 0.3 to 35.5 minutes were solution-treated at 495 C for 8 hours and for 240 hours. All samples were then water-quenched and aged at 260 C for 4 hours. The tensile results show that solidification time and solution treatment time can have significant effects on the tensile properties. In general, as the solidification time increased, the ultimate strength, yield strength, and ductility decreased; increasing the solution-treatment time from 8 to 240 hours improved only the tensile strengths. The amount of Cu available in solid solution to precipitate during aging is found to be a key factor. Additionally, coarse microstructures require very long (and commercially-impractical) solution-treatment times to significantly improve the tensile strengths.
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