High Volume Automotive Applications Research Articles

A new magnesium sheet alloy with high tensile properties and room-temperature formability

Lightweight sheet alloys with superior mechanical performance such as high strength, ductility and formability at room temperature (RT) are desirable for high volume automotive applications. However, ductility or formability of metallic alloys at RT are generally inversely related to strength, thereby making it difficult to optimize all three simultaneously. Here we design a new magnesium sheet alloy-ZAXME11100 (Mg-1.0Zn-1.0Al-0.5Ca-0.4Mn-0.2Ce, wt. pct.) via CALPHAD (CALculation of PHAse Diagram) modeling and experimental validation. This new sheet alloy offers an excellent RT formability with a high Index Erichsen (I.E.) value of 7.8 mm in a solution-treated condition (T4), due to its weak and split basal texture and fine grain structure. The new ZAXME 11100 alloy also shows a rapid age-hardening response during post-forming artificial aging treatment at 210 °C for 1 hour (T6), resulting in a significant increase of yield strength from 159 MPa (T4) to 270 MPa (T6). The excellent combination of T4 ductility (31%), T4 formability (7.8 mm) and T6 yield strength (270 MPa) in this new magnesium alloy is comparable to that of common 6xxx series aluminum sheet alloys. Thus, this new magnesium sheet alloy is highly attractive for sheet applications in automotive and other industries.

Race to the Top

A £10 million innovative aluminium manufacturing process project has been validated for high-volume automotive OEM applications.

Raceform – (Rapid Aluminium Cost Effective Forming)

A £10 million innovative aluminium manufacturing process project has been validated for high-volume automotive OEM applications.

Towards magnesium alloys for high-volume automotive applications

Abstract Reducing vehicle weight is an important approach for increasing fuel economy, addressing regulatory requirements, and meeting consumer needs. Magnesium alloys are among the lightest structural metals and offer tremendous weight saving potential; however, many technical and commercial barriers limit their use in today's cars and trucks. Following a brief review of historical trends in vehicle weight and automotive magnesium, we describe key barriers to wider adoption of magnesium in high-volume vehicle applications. A discussion of manufacturing and processing, in-service performance, and cost requirements identifies specific development needs and opportunities while framing promising paths forward.

Draping simulation-supported framework for cost- and weight- effective composite design

The importance of design for manufacturability when designing composite structures for high-volume automotive applications is great. One key aspect of the producibility and the quality of the final part, as well as the level of complexity of manufacturing operations, are the formability of fibre fabrics. Simulations of this forming, in the composite industry referred to as draping simulations, can greatly improve the manufacturability of the design. Draping simulations will also indicate where areas become too complex, undrapable, to be able to form using one cloth of fabric. In this paper, the draping simulation's undrapable areas are considered as guidance when defining suitable split lines in a composite structure applying a differential design approach. Here, the simulations are located in a greater framework to provide guidelines for a well-balanced cost and weight-effective composite design, and the integration of draping simulations, as well as the framework, is exemplified in a case study. It is observed that the choice of split lines becomes more methodical and less subjective compared to previous approaches. However, draping simulations today are not optimised for high-volume forming processes, and the work of defining split lines becomes complex. In order not to become too time consuming and complicated, draping simulations are required to use single-step forming processes.

Carbon fibres with ordered graphitic-like aggregate structures from a regenerated cellulose fibre precursor

Abstract The production and characterisation of low modulus carbon fibres is reported from a commercially available regenerated cellulose fibre (Cordenka™). The fibres were heat treated before graphitisation at a temperature of 200 °C. Fibres were then further heat treated and graphitised at a temperature of 2000 °C. Polarised Raman spectra of carbonised/graphitised fibres were recorded. The ratio of two Raman peaks located at ∼1350 cm −1 (D-band) and at ∼1600 cm −1 (2D band) – the I D / I G ratio – was used to follow the onset and development of the carbon/graphitic structure. It is shown, using tensile testing, that single carbon fibres processed at 2000 °C have a modulus of ∼70 GPa and strain at break >2%. A Raman spectroscopic method that follows the shift in the position of the 2D band suggests a modulus of ∼77 GPa. Transmission Electron Microscope imaging of the fibres reveals a sub-structure containing aggregates of oriented concentric turbostratic carbon domains, some of which are reminiscent of carbon nanotubes. These relatively high strength fibres (1.5 GPa) could be possible alternatives to E-glass fibres in low weight (∼30% lighter than E-glass), high volume automotive and marine applications. It is also shown that these fibres can be converted in a woven precursor form to a carbon fibre fabric without the need to weave brittle filaments.

Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

High capacity hydrogenstorage materials: attributes for automotive applications and techniques for materials discovery

Widespread adoption of hydrogen as a vehicular fuel depends critically upon the ability to store hydrogen on-board at high volumetric and gravimetric densities, as well as on the ability to extract/insert it at sufficiently rapid rates. As current storage methods based on physical means--high-pressure gas or (cryogenic) liquefaction--are unlikely to satisfy targets for performance and cost, a global research effort focusing on the development of chemical means for storing hydrogen in condensed phases has recently emerged. At present, no known material exhibits a combination of properties that would enable high-volume automotive applications. Thus new materials with improved performance, or new approaches to the synthesis and/or processing of existing materials, are highly desirable. In this critical review we provide a practical introduction to the field of hydrogen storage materials research, with an emphasis on (i) the properties necessary for a viable storage material, (ii) the computational and experimental techniques commonly employed in determining these attributes, and (iii) the classes of materials being pursued as candidate storage compounds. Starting from the general requirements of a fuel cell vehicle, we summarize how these requirements translate into desired characteristics for the hydrogen storage material. Key amongst these are: (a) high gravimetric and volumetric hydrogen density, (b) thermodynamics that allow for reversible hydrogen uptake/release under near-ambient conditions, and (c) fast reaction kinetics. To further illustrate these attributes, the four major classes of candidate storage materials--conventional metal hydrides, chemical hydrides, complex hydrides, and sorbent systems--are introduced and their respective performance and prospects for improvement in each of these areas is discussed. Finally, we review the most valuable experimental and computational techniques for determining these attributes, highlighting how an approach that couples computational modeling with experiments can significantly accelerate the discovery of novel storage materials (155 references).

Advances in Aluminum Foundry Alloys for Permanent and Semi-Permanent Mold Casting

The permanent (PM) and semi-permanent (SPM) mold processes are commonly implemented for a wide range of aluminum applications. Examples include sophisticated aerospace and military parts, through common commercial castings, and on to high volume automotive applications like engine blocks, cylinder heads and suspension components. This paper describes some recent aluminum alloy developments aimed at expanding the markets available to the PM and SPM foundry industry. Topics covered include developments which address the castability of difficult alloys, alloy developments for high strength and/or high temperature applications, and opportunities for cost savings in the areas of heat treatment.

Overview of Lightweighting Materials Research & Development in the United States Freedomcar and Fuel Partnership

The United States of America’s (USA’s) transportation system is strongly dependent on petroleum as an energy source. Petroleum is used to satisfy 95 percent of the USA’s transportation energy needs, consuming two-thirds of all the petroleum used in the USA. Since roughly 60 percent of the petroleum is imported, the implications of this dependency on energy security are readily apparent. Since 2002, the United States Department of Energy (USDOE) and the United States Council for Automotive Research (USCAR) have worked cooperatively through the FreedomCAR and Fuel Partnership (FC&FP) to fund high-risk, high-payoff research and development (R&D) into advanced automotive technologies with the potential for lowering this dependence. The FC&FP succeeded and built upon the Partnership for a New Generation of Vehicles (PNGV) initiative that ran from 1993 to 2001. The long-term transition of vehicles from gasoline to non-petroleum energy sources is viewed as critical in lowering the dependence of the USA economy on foreign oil, and in reducing the environmental impact of the personal transportation sector. The FC&FP supports research on technologies with the potential for energy-efficiency and renewable energy benefits, such as new engine concepts, lightweight materials, alternate non-petroleum based fuels, and hybrid propulsion components. This paper will highlight the research in the lightweight metals portion of the FC&FP. Cooperative R&D projects will be discussed which focus on processing and manufacturing technologies such as casting of magnesium (Mg) and aluminium (Al) alloy components, advanced forming techniques for Al sheet, and warm-forming of Mg sheet. The overall objective of these efforts is not only to demonstrate new technologies, but to reduce the cost of manufacturing lightweight materials and enable implementation of the technologies in high-volume automotive applications.

Lower Emissions with DLC Coatings

The results are presented of an investigation into the effects of Diamond-Like Coatings (DLC) on the frictional behaviour of components within the valve train of a production engine. Components from a 40-cylinder, 1.6 litre Peugeot petrol engine were coated with Bekaert's Dylyn Plus, a coating specifically aimed at high volume automotive applications and with properties that can be tuned precisely to match the customer's needs. Tests were run on an electrically driven test rig using coated and uncoated mechanical and hydraulic tappets. The results were measured at 20, 50, 80 and 120degreesC where 20degreesC was considered to be a normal start-up engine temperature and 80 - 120degreesC the normal working temperature for an engine. The results for torque reduction are presented graphically. In the low rpm range friction reduction, and therefore energy requirement, was reduced by 24 per cent but this decreased with higher rpms. It is estimated that a reduction in fuel consumption of 1-2 per cent could be achieved implying a reduction in carbon dioxide emission of 2-3 per cent. It is suggested that the benefits of DLC coating would be most beneficial to smaller petrol cars.

Design of magneto-rheological (MR) valve

Abstract Magneto-Rheological Fluid (“MRF”) technology has been successfully employed in various low and high volume automotive applications. Good understanding of specific design constraints is required to define and to optimize a magneto-rheological device. This article presents parametrical analyses with magnetic simulations, of a magneto-rheological valve and a magneto-rheological orifice. Experimental rig assemblies of two different control devices have been designed, built and the performances have been evaluated experimentally. Controlled pressure drops, of 0.6 MPa @ 4.5 A at 5 cm3/s in the orifice mode, and 1.5 MPa @ 4.5 A at 0 cm3/s, in the valve mode, using MRF132-AD, have been achieved. The study shows that excellent features like the fast response and the contactless nature of MRF control are attractive for various control devices.

Cure shrinkage characterization and modeling of a polyester resin containing low profile additives

Resin Transfer Moulding (RTM) has great potential as an efficient and economical process for fabricating large and complicated composite structural components. The low capital investment cost required and process versatility in component integration and assembly make RTM very attractive for high volume automotive applications. One of the challenges facing the automotive field is the resulting surface finish of manufactured components. The shrinkage associated with the curing of thermoset resins contributes to the poor surface quality. Low profile additives (LPA) are added to the resin to compensate for the cure shrinkage; however their effects on the thermal, rheological and morphological properties of polyester resins are not well understood. In this paper, the effect of LPA on cure kinetics, cure shrinkage and viscosity of a polyester resin is studied through differential scanning calorimetry (DSC) and special rheological techniques. Models are developed to predict cure shrinkage, LPA expansion, cure kinetics and viscosity variations of the resin as a function of processing temperature. Finally, morphological changes in the resin with and without LPA, during isothermal cure, are studied with hot stage optical microscopy. The results show that the LPA content in the range tested had no significant effect on the cure kinetics. However, higher LPA content reduced cure rate and cure shrinkage. A minimum of 10% LPA was required to compensate for cure shrinkage. Shrinkage behavior of all formulations was similar until a degree-of-cure of 0.5. However, resin formulations with higher LPA content showed expansion at later stages during curing.

Effect of processing on microstructure, texture and mechanical properties of twin roll cast 5754 sheet

Weight reduction in passenger cars improves fuel economy, performance, safety and reduces emissions. Aluminium currently offers the greatest potential for cost effective weight savings in automotive body structures owing to its ability to reduce vehicle's weight without a loss in performance. The major barrier to the widespread use of Al in high volume automotive applications has been its high cost. This makes the implementation of the twin roll casting (TRC) technology in the manufacture of Al sheet very attractive. It has recently been shown that TRC Al–Mg sheet can be a suitable substitution for its direct chill (DC) cast counterpart. The present paper reports the results of an investigation undertaken to evaluate the microstructure, texture and properties of 1·0 mm thick O temper 5754 sheet manufactured by TRC technology for inner panel applications. The response of TRC 5754 alloy to different down stream processing cycles were investigated.

Short-term static and cyclic behavior of two automotive carbon-fiber composites

Abstract The basic static (tensile, compressive, and in-plane shear) and fatigue properties, including temperature and fluid environment effects, for two carbon-fiber polymeric composites, produced by a rapid-molding process suitable for high volume automotive applications, are described. The two composites had the same urea/urethane matrix and were reinforced with stitch-bonded carbon-fiber mats, in a crossply layup in one case, and in a quasi-isotropic layup in the other. All properties were determined over a temperature range from −40 to 120 °C, and the degradation of the properties due to distilled water and windshield washer fluid was established. In all cases, two fiber orientations of the crossply, 0/90° and ±45°, relative to the specimen axes were addressed. As expected, matrix-dominated properties were degraded more by rising temperatures than were fiber-dominated properties. Fluid had only a modest effect in both cases. Basic fatigue behavioral characteristics were established through tensile fatigue tests over the temperature range of interest. An assessment of fatigue test results for the two composites revealed differences in a progressive loss in stiffness and an increase in permanent strain, both of which are indicative of increasing damage. In all cases, fatigue reduction factors were established to account for the effects of temperature and fluids.

Low-energy impact effects on candidate automotive structural composites

The objective of the work described in this paper was to experimentally characterize the susceptibility of three candidate automotive structural composites to incidental, low-energy impact damage. The composites, each of which had the same urethane matrix, were produced by a rapid molding process suitable for high-volume automotive applications. The reinforcement for the first composite was a random chopped-glass fiber, while the remaining two were reinforced with stitch-bonded carbon-fiber mats, one in a crossply layup, and the other in a quasi-isotropic layup. A pendulum device, representative of events such as tool drops, and a gas-gun projectile, representative of events such as kickups of roadway debris, were used to impact plate specimens. Brick-drop tests were also performed to assess the applicability of the baseline pendulum and gas-gun data to other events. Following the impacts, the damage areas were measured and the plates were cut into either tensile, standard compressive, or compression-after-impact specimens for determining strength degradation. The glass-fiber composite was least susceptible to damage, followed by the crossply carbon-fiber laminate, which had the same thickness. The quasi-isotropic carbon-fiber composite, which was thinner than the other two, sustained the most damage. While compressive strength was significantly degraded by moderate damage in the random-glass-fiber composite, tensile strength was not. On the other hand, both tensile and compressive strengths were degraded in the crossply carbon-fiber laminate (only compressive strength loss was measured in the quasi-isotropic laminate). Compressive strength degradation for a given damage area was similar in the two carbon-fiber laminates. Both showed lesser degradation than did the glass-fiber composite. For the quasi-isotropic carbon-fiber laminate, it was shown that strength degradation produced by an open circular hole provides a reasonable lower bound to the degradation due to an impact damage area of the same size.

Durability-based design criteria for a chopped-glass-fiber automotive structural composite

This paper describes durability-driven design criteria developed for the use of a chopped-glass-fiber polymeric composite in automotive structural applications. The composite, which was made by a rapid molding process suitable for high-volume automotive applications, consisted of a chopped-fiber E-glass mat, made by the programmable powder preform process (P4), in a urea/urethane matrix. The durability issues addressed include the effects of cyclic and sustained loadings, temperature extremes, and automotive fluid environments. The paper briefly describes the laboratory tests, summarizes the results, and explains how the experimental information was used to formulate coherent and practicable design criteria. The criteria include design analysis guidance, a biaxial strength criterion, time-independent and time-dependent allowable stresses, and rules for assessing cyclic loadings. Environmental degradation factors and the degrading effects of prior loadings are included.

Challenges of the emerging microsystems industry

The microsystems industry is now a rapid growing industrial sector that has emerged during the three last decades. The onset was mainly a technological spin-off from microelectronics/integrated circuit technology. Silicon micromachining gave the main triggering technology push as a very promising process technology with distinctive features. Sensor applications gave the first market opportunities, and batch-organised processing technology adapted from the microelectronics industry the key to high quality at low cost. Today, this has matured into a separate industry sector with their own market and manufacturing infrastructure, also with a limited use of other materials than silicon. The microsystems are used in electronic systems with widespread applications, ranging from low cost, high volume automotive applications to high cost, low volume instrumentation applications. Key technological success and inhibitor factors for this industry are discussed. It is proposed that the most important are market opportunities, microelectronics manufacturing infrastructure and micromachining. In the future, computer-aided design and simulation tools will also gain importance. Examples from research and manufacturing of microsystems, mainly from SensoNor and SINTEF Microsystems in Norway, are used to illustrate these factors. It is proposed that the most important challenge for SensoNor is the transition from being sensor company to becoming a true microsystem company.

Use of a charged coupled device (CCD) camera for evanescent wave optical fiber cure monitoring of liquid composite molding resins

AbstractAn optical fiber evanescent wave fluorescence cure sensor described in a previous paper (1) has been interfaced with a fast detector and computer software to provide real‐time monitoring of fast‐reacting systems. Advantages to the new system include a reduction in data acquisition time (to 200 ms from 3 min), improved time resolution (to 5 sec from 10 min), and improved signal quality. Isothermal cure monitoring measurements were conducted in both distal and evanescent wave sampling modes for an epoxy‐amine system. Following a second order background correction, the results for the two sampling modes were identical. Thus the evanescent wave measurement was unable to detect differences between the chemistry in the bulk and at the fiber‐resin interface (if there were any differences to observe). The sensor system was also demonstrated for a fast curing (<3 min gel time) polyurethane‐isocyanurate system designed for high volume (short cycle time) automotive applications. The system is currently being modified for implementation in a “real world” manufacturing environment.

MCM-L Technology: a systems cost analysis for a high volume automotive electronic applications : JOHN L. EVANS, LARRY E. BOSLEY, CHRIS S. ROMANCZUK and R. WAYNE JOHNSON. IEEE Transactions on Components, Packaging and Manufacturing Technology, Part B, 18(1), 28 (February 1995)

MCM-L Technology: a systems cost analysis for a high volume automotive electronic applications : JOHN L. EVANS, LARRY E. BOSLEY, CHRIS S. ROMANCZUK and R. WAYNE JOHNSON. IEEE Transactions on Components, Packaging and Manufacturing Technology, Part B, 18(1), 28 (February 1995)