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Technical Paper

Use of Thermally Conductive Electrically Insulative (TCEI) Materials in E-motor Slot Liner Applications

2022-03-29
2022-01-0198
Slot liners are commonly used in electric motors to electrically insulate the motor windings from the laminated core. However, thermal conductivity of materials commonly used as slot liners is very low compared to other components in the motor thus creating a barrier for heat transfer. This thermal barrier affects overall motor performance and efficiency. Also, slot liners typically lack intimate contact with the laminated core resulting in air gaps which further increase thermal resistance in the system. Slot liners are traditionally made from high temperature films/papers that are cut and slid into slots of motors. The proposed work looks at developing an injection moldable slot liner to minimize air gaps. Additionally, use of TECI materials further lowers thermal resistance. A thermal finite element model has been developed to evaluate effects of slot liner thermal properties and air gaps on temperature distribution within the motor.
Technical Paper

Forming Characteristics of Very Low Carbon High strength Dual Phase Steels Produced through a Flex Mill Continuous Galvanizing Line

2022-03-29
2022-01-0239
A low carbon, lean alloyed chemistry was selected for the development of high strength dual phase (DP) steels with enhanced global and local formability. Optimized best process conditions including clean steel practices, choice of suitable casting powder, hot rolling and continuous anneal set points resulted in excellent mechanical properties and formability characteristics of DP steels. The enhanced balance of strength and formability is attributed to the optimization of the microstructure through refinement, uniformity and balancing microconstituents mechanical response and guaranteeing outstanding internal cleanliness. In this contribution, production strategy and formability characterization of DP steels with tensile strengths of 780 MPa and above relevant to automotive body structure applications will be discussed.
Technical Paper

Development of a transmission-illumination-based crack detection method using translucent tools for testing of thin-walled metal sheets and foils

2022-03-29
2022-01-0242
The formability of thin-walled metallic sheets and foils is increasingly gaining in importance in the automotive industry and in medical and food packaging. As a result, the demand for methods to test the deep drawing and stretch forming capabilities of these materials is increasing significantly as well. In deep drawing and stretch forming, the in-situ crack detection is either performed manually by purely visual evaluation by the machine operator or automatically by a crack detection system. The automatic crack detection method commonly integrated in sheet metal testing machines functions by analyzing the drawing force during forming. However, friction, vibration, and machine noise are disturbance variables that prevent crack detection in thin sheets and foils. The same disturbance variables also prevent robust crack detection in thin sheets and foils by systems that analyze structure-borne sound.
Technical Paper

Local Thermomechanical Processing for Improving Formability of High Strength Aluminum Sheets

2022-03-29
2022-01-0244
Limited room temperature formability hinders the wide-spread use of high strength aluminum alloys in structural body-in-white parts. Stamping or extrusion at warm temperatures or from softer tempers are the current solutions. In this work, our approach is to start with age- and work-hardened sheets from 7xxx, 6xxx, and 5xxx family of alloys and improve their formability using local thermomechanical processing only in the regions demanding highest ductility in the forming processes. The processes used were friction stir processing (FSP) and roller bending-unbending. In both the methods sheets were locally deformed and heated simultaneously without any change in the final sheet geometry or chemistry. Initial results indicated significant deformation in the processed zones with minimal sheet distortion. FSP also resulted in dynamically recrystallized, fine grained (d <5 µm) microstructures in the processed regions with textures significantly different from the base material.
Technical Paper

Adjoint method in optimizing conformal cooling channels of 3-D printed high-pressure tools for aluminium casting

2022-03-29
2022-01-0246
The emergence of additive manufacturing (AM) technology has enabled the internal cooling channel layout for high pressure aluminium die casting (HPADC) tools to be designed and modified without topological constraint. Optimisation studies of a full industrial HPADC mould for extending the tool service life has received limited attention due to the high geometrical complexity and the various physics with multi time and length scales in addition to the manufacturability limitations. In this work a new computational efficient algorithm that employs the adjoint optimization method has been developed to optimize the coolant channels layout in a complete mould with various 3D printed inserts. The algorithms reduced significantly the computational time and resources by decoupling the fluid flow in the coolant channels from the tool and simulating them separately.
Technical Paper

Fatigue Damage of Trim Dies Manufactured or Reconditioned by Different Routes

2022-03-29
2022-01-0245
The compression fatigue behavior of sheet metal trimming die is studied. The trim dies were manufactured or reconditions through different fabrication processes and heat treatment conditions. An accelerated lab testing method is developed to evaluate die damage resistance under compressive cyclic load applied at the tool edge, analogous to sheet metal trimming die operation. The metal removal volume at the sheared edges were measured by image processing to quantify the degree of fatigue damage as a function of loading cycle number. The fatigue microstructural damage were examined with optical and scanning electron microscopies. The simulated die performances are compared among different die processing routes. A phenomenological trim die damage rate model in Paris law form was obtained and tuned with experimental data for tool life prediction.
Technical Paper

Padded Self-Piercing Riveting (P-SPR) on magnesium high pressure die casting

2022-03-29
2022-01-0249
Padded self-piercing riveting (P-SPR) is a newly developed multi-material joining technology to enable less ductile materials to be joined by self-piercing riveting (SPR) without cracking. A deformable and disposable pad was employed to reduce the stress distribution on the bottom surface by supporting the whole bottom sheet continuously during rivet setting process. To verify the P-SPR process, 2.0mm thick 6061-T6 wrought aluminum was joined with 3.2mm thick coated AM60B magnesium high pressure die casting (HPDC) by using 1.0mm thick dual-phase 600 (DP600) steel as the pad. Regular SPR processes with 2 different die geometries were studied as a comparison. Compared to the regular SPR processes, P-SPR demonstrated advantages on coating protection, crack mitigation and joint strength.
Technical Paper

Thermomechanical behavior of an automotive exhaust aftertreatment application

2022-03-29
2022-01-0277
An aftertreatment system is the back-end component of an automotive exhaust system, used mainly to reduce pollutant emissions. This system is exposed to high thermal loads which can exceed temperatures of 900 oC , usually they operate at temperatures under 600 oC - 700 oC, depending of the engine application. The durability assessment of a system under thermomechanical loads can be challenging due to the complexity of the technical problem, which involves complex material behavior at high temperatures and results in high thermomechanical strains and stresses. This study presents a computational approach for the lifetime assessment of an exhaust aftertreatment system subjected to thermomechanical loading. The method is composed of a fluid flow analysis to compute the temperature fields which are mapped to a mechanical analysis combined with a nonlinear elastoviscoplastic material behavior. Lastly, the lifetime of the overall assembly is assessed through a fatigue analysis.
Technical Paper

Effect of geometric parameters on folding of thin-walled steel tube under axial compression

2022-03-29
2022-01-0264
This study investigated the plastic deformation behavior of 304 stainless steel thin-walled tubes under axial compression by means of numerical calculation and theoretical analysis. It was found that the plastic deformation length of thin-walled tube determined the formability of folds and the work done in the whole axial compression process. To reveal the relation between the range of plastic deformation length and tube geometry parameters, regression equations were established using the quadratic regression orthogonal design method. Experiments were conducted to validate the equations. The process windows for forming a single fold and tube joining at ends had been printed ultimately. The results showed that the regression equations can accurately predict the range of plastic deformation length for forming a single fold.
Technical Paper

Effect of Decoration on Windshield Impact Resistance and Novel Decoration Solution Compatible with Chemical Strengthening

2022-03-29
2022-01-0263
Vehicle windshields typically include a black decorative pattern around their periphery and other regions. Examination of field failed parts has shown that windshields often break from impacts in these decoration zones; often with the fracture initiating from the decoration material itself. In this work, the effect of different glazing decoration materials on glass strength and laminate impact resistance was evaluated. The decoration materials investigated included traditional inorganic enamel frit, an organic ink, and a new enamel frit that is compatible with glass chemical strengthening. Ring-on-Ring strength tests were conducted and showed that inorganic enamel frit reduces strength of glass by over 50% compared to undecorated glass, while organic inks do not adversely affect strength. Tests of a newly developed decoration frit material, compatible for chemical strengthening processes, showed strength levels that were on par with undecorated, unstrengthened glass.
Technical Paper

Polypropylene composite material for light weight fuel tank protection shield

2022-03-29
2022-01-0336
The fuel tank shield provides a protective boundary between the fuel tank and vehicle driveline in the event of a high-speed crash. Hence, it is important from the safety standpoint. The part must be carefully engineered to meet the challenging requirements in terms of stiffness, deflection, toughness, dimensional stability and thermal stability. In this paper, long glass fibre filled polypropylene material compound was selected and developed to meet the mentioned requirements for this part with significant mass reduction over other materials. The combination of material, optimized part and tool design led to weight savings and considerable cost reduction. This is a ready to mold material used in injection molding process.
Technical Paper

Wear and Corrosion Behaviours of PEA Alumina Coatings on Gray Cast Iron

2022-03-29
2022-01-0329
Alumina (Al2O3) thin film coatings are applied on Al alloys using Plasma Electrolytic Oxidation (PEO) method to reduce the wear and corrosion problems. Plasma Electrolytic Aluminating (PEA) is a technique that could generate Alumina coatings on cast iron, mild steel, and copper alloys. In this study, the aim is to explore the anti-wear and anti-corrosion behaviours of PEA Alumina coatings on gray cast iron. The dry sliding tribology test data was obtained from Pin-on-Disk (POD) tests against SAE 52100 steel and Tungsten Carbide (WC) counterfaces. Comparing to the PEO Alumina coatings, the PEA Alumina coating has a much lower Coefficient of Friction (COF) and less wear. The microstructure, chemical composition, and phase composition of this coating were investigated with Scanning Electron Microscope (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), and X-Ray Diffraction (XRD), respectively. There was FeO (or FeAl2O4) found on the PEA Alumina coating.
Technical Paper

Polyetherimide for magnet wire application

2022-03-29
2022-01-0334
Magnet wire is composed of conducting core and thin layer of electrical insulation. Cupper (Cu) is typically used as conducting core, and various polymers such as polyamideimide, polyimide, and polyesterimide are used for electrical insulation. The role of magnet wire is involved in interchanging between electrical energy and mechanical energy for energy transformation application such as transformer, motor, generator, and many other equipment. Currently, electric vehicles (EV) industry is rapidly growing and consequential demands on related components are increasing as well. Compared to combustion engine, EV needs more electrical power with higher voltages or higher currents, which can increase probability of electrical discharge. The degradation of insulation layer can happen with the polymer bond breakage under the partial discharge electric stresses.
Technical Paper

An Investigation of the simulation of sintering distortion in a 316L Part manufactured using Bound Metal Deposition 3D printing

2022-03-29
2022-01-0346
Metal binderjetting is a high throughput additive manufacturing process that has the potential to meet the needs of automotive volume production. In many cases, this process requires a sintering post-process to meet final dimensions. Because the sintering stage is performed free standing (i.e. without the use of tooling) and can involve up to a 20% dimensional change from green part to the final part shape, part distortion can be a concern. In this study, the sintering stage of a bridge geometry was simulated under different parameter settings using a Finite Element Analysis. The sensitivity of the simulation to various process parameter inputs was examined. Parts were then produced in 316L using a bound metal deposition and sintering process and compared to prediction. The sintering simulation indicated good agreement with experiment for some dimensions but highlighted the need for additional analysis.
Technical Paper

Ultimate Breakage Load Calculation Method of Cold Gas Inflator Burst Disk

2022-03-29
2022-01-0764
For cold gas Inflator, high refinement of ultimate load forecast is one key of Inflator development. At beginning, two methods based on implicit algorithm, Zero Curvature method and RIKS method were used for burst disk hydro-burst test ultimate pressure load calculation. After considering the effect of bursting disk stamping process, comparing with results of real test, the refinement of the two methods were above 97% both. Studying the corresponding relations between displacement and stress matrix of the center point of burst disk by RISK method. It was found that under ultimate load, the third principal stress vs. displacement curve of the central node shown extreme point, and load step of the point was corresponding the one of maximum pressure load. This shown that after reaching the ultimate load, the center of the bursting disc lost stability in the direction of thickness.
Technical Paper

Nonlinear Finite Element Calculation of Cold Gas Inflator Housing Ultimate Breakage Load Based on Arc-Length Method

2022-03-29
2022-01-0766
For cold gas Inflator, high refinement of ultimate pressure load forecast of inflator housing is one key of Inflator development. For inflator housing hydro-burst test ultimate load FEA calculation, arc-length method is utilized for obtaining high precision results. At beginning, the material parameters of inflator housing for simulation is correlated. The FEA material model adopts the stress-strain data from uniaxial tensile experiments. Considering the geometrical nonlinearity resulting from large deformation as well as material nonlinearity from plastic hardening, the whole tensile process from tensile deformation to failure of the specimen is stimulated by utilizing the arc-length method. Numerical results show that the arc-length method is appropriate to predict the entire deformation process, and the obtained key deformation stages, the distribution and inclined angle of the localized necking occurs also agrees with that of theoretical analysis.
Technical Paper

Integrated Wheel Assembly Designing and optimization for BAJA SAE ATV

2022-03-29
2022-01-0795
The conventional Wheel assembly is optimized using Stub and Hub integration by researching and evaluating new assembly designs, Material selection using Charpy impact test on different materials (EN24, 20MNR5, EN36) with different hardening processes (through hardening, Carburizing) are evaluated for the best combination of material and type of hardening which absorbs highest impact energy, which further evaluated for different types of brittle and ductile failure on those specimens, Component designing is performed considering various boundary condition evaluated for BAJA SAE ATV which includes Bump force due to hill fall down, Tension/Compression generation in case of improper landing on wheels, Torsion transfer through axle and Lateral forces due to centrifugal forces were used for design calculation and then FEA is used for Design validation. Finite model is generated in Hypermesh using various Meshing techniques considering rotating symmetry for achieving good quality criteria.
Technical Paper

Novel Nanocrystalline Silver Alloy Coatings to Boost Performance of EV High Voltage Interconnects and Charging Interfaces

2022-03-29
2022-01-0723
Electric vehicle performance needs challenge connector designers and powertrain engineers with new paradigms for performance under more rigorous operational conditions. Traditional connector design protocols direct the engineer to silver plating for the contact interface, but these coatings have a maximum interface temperature of 170 C (ambient temperature plus T-rise). To avoid thermal runaway, engineers have to derate the ampacity of powertrain connections, which reduces available energy delivery as the temperature increases. This is especially true during transient power events like regenerative braking and acceleration. The soft nature of silver coatings make them well suited for power delivery and low contact resistance, but requires an engineering trade-off for wear durability. This is especially problematic for charging connectors which require tens of thousands of mating cycles before failure.
Technical Paper

Research on electromagnetic shielding technology of special vehicle-mounted shelter based on material-structure co-design

2022-03-29
2022-01-0351
In order to meet the needs of modern warfare, the research on electromagnetic shielding technology of military vehicle-mounted shelters and improving the electromagnetic shielding performance of shelters will play an increasingly important role in the protection of advanced electronic equipment. At the same time, it is also the core of the development of military vehicle-mounted shelters. In this paper, by selecting and comparing different materials, using multi- layer composite materials to design the military vehicle-mounted shelter. The shelter body comprises a front wallboard, a rear wallboard, a left wallboard, a right wallboard, an upper wallboard and a lower wallboard.
Technical Paper

Ultra High Pressure sensor with MEMS sensor element mounted on the measurement membrane manufactured by MIM

2022-03-29
2022-01-0417
This paper presents a ultra high pressure sensor composed the measurement membrane manufactured by MIM(Metal Powder Injection Molding). The membrane should be sufficiently deformed within the measuring pressure range and not be broken at the burst pressure. Therefore, in general, the high pressure sensor membrane made of metal using machining methods such as milling and drilling [1]. However, it requires additional process to assembly with other parts and is difficult to make complex structure such as screw. Thus, in this paper, we propose the product and design of the measurement membrane using the MIM method. We have developed the ultra-high pressure sensor capable of measuring to 900 bar.gauge. Figure 1 shows the ultra-high pressure and measurement part. The measurement membrane thickness is 900 ㎛ and diameter is 3.2 mm. The MEMS sensor element mounted on the measuring membrane surface outputs an electrical signal according to the pressure.
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