Magnesium Development as a Lightweight Material—In Competition with Other Structural Materials

To contribute to the environmentally friendly concept; trends and directions of vehicle manufacturing in the world automotive industry have focused on energy-saving vehicles and carbon-monoxide emission reduction. These affect Thai manufacturers to produce light and safe automobiles (the next generation) using lightweight materials and advanced high-strength steels (AHSS). The objectives of this study were 1) to study the readiness of enterprises in the Thai automotive-parts industry in producing automotive parts by using lightweight materials and advanced high-strength steels, 2) to gather their limitations in producing lightweight automotive parts, and 3) to seek recommendations from specialists in Thai Automobile industry to deal with the limitations. This study employed a qualitative methodology. The research instrument was an in-depth interview. The participants were 17 administrators of car-assembling companies, executives from Tier 1, Tier 2 and Tier 3 automotive parts companies/suppliers, and specialists from the automotive industry. The data gained were analyzed through content analysis. The results from this study indicated that small-sized companies in the automotive industry still lacked the knowledge and experience to produce their parts using lightweight materials, requiring external specialists to support them. On the other hand, big-sized companies and joint-venture companies are able to produce their parts with lightweight materials by themselves. In addition, the specialists recommended guidelines for the die design and production from the start to the end stage. The lightweight materials would be more widely used in the Thai automotive industry if their costs were approximately the same as the current materials.

Advanced High Strength Steels or AHSS (Advanced High Strength Steels) have superior properties to conventional steel are widely used in the automotive industry, they provide weight reduction and at the same time, increase vehicle safety in the event of collisions.Flangeability is an essential element for forming automotive components such as chassis and suspension components.Research is ongoing into the development of forming techniques that can improve the performance of AHSS during industrial operations, particularly flange drawing.Therefore, there is great interest in investigating the extensibility of the pre-cut cutting edge and determining the factors that significantly influence the formability of the product.The test used to evaluate flangeability is the Hole Expansion Ratio (HER).In this research, the objective was to evaluate the influence of the conditions of four edge cutting methods on the hole expansion test of advanced multiphase high-strength steel class 780 MPa through four methods: Machining, LASER and punching with expansion of the hole in the direction of the punch (burr downwards) and in the opposite direction (burr upwards).The results of this study corroborate the literature that indicates that the state of the edge after cutting directly influences the expansion capacity of the hole.

To improve crash worthiness and fuel economy, the automotive industry is, increasingly, using Advanced High Strength Steel (AHSS). The main reason to utilize AHSS is their better performance in crash energy management, which allows one to down gauge with AHSS. In addition, these engineered AHSS address the automotive industry’s need for steels with higher strength and enhanced formability. The improved capabilities the AHSS bring to the automotive industry do not bring new forming problems but certainly accentuate problems already existing with the application of any higher strength steel. These concerns include higher loads on presses and tools, greater energy requirements, and increased need for springback compensation and control. Springback problem, consistently, is one of the leading roadblocks hindering auto stamping productivity. This paper describes the origins and types of springback, characterizes what causes it, and elaborates ways to rectify it through, stabilization, compensation, and verification.

Challenged to improve safety and fuel economy, automakers continually search for new materials to meet high standards. Several factors drive the material R&D and selection for automotive applications, including safety, fuel efficiency, environmentalism, manufacturability, durability, and quality. In the highly competitive automotive industry, cost is an extremely important factor in material selection. As the motivation to reduce the mass of vehicles continues to grow, automakers seek to maximize the efficiency of their materials selection. Materials in automotive applications are selected to minimize weight while meeting key criteria, including crash performance, stiffness, and forming requirements. Since the 1920s, steel has been the material of choice for automakers worldwide. The weight percentage of steel used in vehicles relative to other materials has grown from around 50% in the early 1980s to about 60% in 2010 for North American light vehicles. Today, steel makes up around 65% of an average automobile’s weight and is the backbone of the entire vehicle. On average, that is 900 kg of steel used per vehicle. To further enhance passenger safety, vehicle performance, and fuel efficiency, reducing the weight of vehicles has become one of the top priorities for the automotive industry. Advanced high-strength steels (AHSSs) are a new generation of steel grades that provide much higher strength and other advantageous properties than other materials while maintaining the high formability required for manufacturing. AHSSs help engineers meet requirements for safety, efficiency, emissions, manufacturability, durability, and quality at a low cost. The relevance of AHSSs is quickly increasing in the automotive industry, and AHSSs are the key material for vehicle mass reduction. Different types of AHSS help parts meet the varied performance demands in different areas of the vehicle, including both the crumple zone and passenger compartment.

As lightweight automotive structures improve fuel efficiency and reduce carbon dioxide emission, they have garnered extensive attention. Vehicle mass reduction, which is a key problem for next generation eco-friendly vehicles, can significantly increase mileage. Hence, industries have committed to replace conventional materials with lightweight materials, such as advanced high strength steel. Additionally, automotive industries are hindered by challenges in the field of joining technology. A novel welding technology called resistance element welding (REW), which is an appropriate thermal-based joining method, was developed recently for joining hybrid materials with other structural steel grades. In this study, the state of the art joining and the process characteristics for dissimilar metal joints have been presented because related studies show limited investigation in this area. Following by the state of them, the principal and welding quality of REW, experimentally and numerically, are reported to give comprehensive information on the current practices and research interest related to technologies. Finally, extensive work was concentrated on portional joining optimization techniques to improve different materials.

The automotive industry is using more and more advanced high strength steels (AHSS), aiming at reducing vehicle weight, minimizing emission, increasing fuel economy, and improving vehicle safety. This article focuses on the AHSS products recently developed at Nucor Corporation. With innovative chemistry and process designs, as well as a strictly controlled manufacturing operation carried out during the unique CSP® and down-stream processes, these newly developed steels possess finer, more uniform microstructure, with modified morphology and optimum fraction for each phase. Compared to the most commercially available AHSS, these new materials have higher strength-elongation balance, improved formability and stretch flangeability, enhanced impact toughness and crashworthiness, good coating or surface quality, as well as superior weldability and weld fatigue properties. Moreover, the property consistence of these innovative AHSS has been markedly improved.

Due to economic and ecological trends, materials used in the automotive industry are expected to be lightweight. One of the most important advantages of lightweight materials is a reduction of raw material consumption, which results in lower production costs. In the automotive and aviation industry, one of the most important features of lightweight material is its density. Obtaining material with lower density allows to reduce a total weight of a vehicle, which causes improved performance and lower fuel consumption. One of the key solutions used to produce lightweight parts in the automotive industry is microcellular injection molding (MIM), which allows obtaining a part characterized with microcellular structure, consisting of plastic and gas pores inside of a part. The most important challenge in creating lightweight materials is to achieve comparable mechanical properties to the state before density reduction. This kind of result is possible to achieve by the control of porous material’s structure, primarily gas cells size, amount and distribution.This work presents the influence of gas injection parameters on a part’s structure, examined with use of 2 injection simulating tools and in actual experiment, where the structure was tested in use of computed microtomography. The second aim of the work was to compare results obtained in 3 different ways, which were: Moldex3D simulation, Cadmould simulation and an actual experiment.

The automotive industry is constantly involved in the development of new projects aimed at reducing weight, fuel consumptions and costs while improving passengers? safety. In order to achieve these increasing demands, Advanced High Strength Steels (AHSS) have been introduced in recent years reducing vehicle structure weights and improving the crashworthiness. With the increase in the bearing capacity of crash-relevant structural components, the sheet metal joining techniques such as adhesive bonding and resistance spot welding (RSW) become critical. In order to develop the vehicle structure in these new projects, full-vehicle crash finite element simulations are usually performed. Simplified beam-like models are currently used in these simulations (with thousands of spot welds) to represent RSW joints response. The maximum bearing force of these models are fitted using large experimental campaigns, considering all the main factors that have the highest influence on the fracture response of a welded joint. The objective of this thesis is twofold: (1) to develop a model that is able to partially replace the extensive experimental campaign in providing parameters for the crash simulation simplified spot weld models, and (2) to gain understanding of spot weld joints failure response in order to improve the current simplified models. To achieve these objectives, a detailed spot weld model for the prediction of spot weld failure in joints in AHSS sheets is presented. The presented model includes a definition of the local material properties as well as the geometry features of a spot weld. In addition, an industrially suited fracture criterion, i.e. robust and without a long-term calibration, is used for the prediction of maximum force. An energetic fracture criterion based on the use of elastic-plastic fracture-mechanics is identified as the better suited for the prediction of spot weld failure and joint bearing capacity. The J-integral is evaluated in the weld notch and this value is compared with a material parameter, the fracture toughness, in order to obtain the joint maximum force. The presented detailed FE spot weld model is validated to joints of two different steel grades of the AHSS family usually present in the current vehicle structure, a hot formed martensitic boron-alloyed steel (22MnB5) and a cold formed dual phase steel (DP 980). The validation is performed comparing the results obtained with the finite element model and the experimental results extracted from an extensive loading test experimental campaign where the main factors that have an influence in the spot weld fracture response are considered. The obtained simulated critical forces of the loading tests present good agreement with the experimental ones in all tested configurations. Finally, based on the presented finite element spot weld model, some recommendations are exposed for extending the model for new combinations and loading conditions. The proposed procedure can be used to reduce the long-term characterization campaigns used to calibrate the joints of a new AHSS grade, where fracture is triggered by stress concentration ahead of a notch. Furthermore, some recommendations for the future structure design are given taking into account the information obtained with the present model.

Stringent carbon emission targets and consumer demands for highly fuel efficient and safe vehicles are driving most of the innovations in the automotive industry. In the present era, the prime technological goal of the automotive industry is to design and manufacture commercially viable lightweight vehicles while maintaining the structural performance of the vehicles at the same time. Development of Advanced High Strength Steels (AHSS) is an important step forward in this context. However, plastic deformation induces damage in AHSS. Damage development during the forming process renders the classical failure prediction techniques ineffective, which poses difficulties in designing the forming process. Therefore damage development in these steels has been studied and incorporated in numerical simulations for accurate failure predictions in forming processes and for determination of the product properties after forming. Damage development is anisotropic by nature and shall be considered anisotropic for accurate failure predictions. In this research, anisotropy in damage has been classified into two categories; Material Induced Anisotropy in Damage (MIAD) and Load Induced Anisotropy in Damage (LIAD). MIAD is related to the anisotropy in distribution and shape of second phase particles or impurities and is governed by void/crack nucleation. LIAD is related to the loading direction of the material. The phenomenon of MIAD was discovered during this research. This is the first research showing the occurrence of MIAD in AHSS. The standard Lemaitre anisotropic damage model was modified to incorporate: lower damage evolution under compression, strain rate dependency in damage and Material Induced Anisotropic Damage (MIAD). Viscoplastic regularization of damage models was revisited. This technique proved to be effective in removing the pathological mesh dependence of local damage models. The damage model parameters for the same grade of DP600 were determined. The Modified Lemaitre’s (ML) anisotropic damage model was validated with experiments.

The world’s most common alloy, steel, is the material of choice when it comes to making products as diverse as oil rigs to cars and planes to skyscrapers, simply because of its functionality, adaptability, machine-ability and strength. Newly developed grades of Advanced High Strength Steel (AHSS) significantly outperform competing materials for current and future automotive applications. This is a direct result of steel’s performance flexibility, as well as of its many benefits including low cost, weight reduction capability, safety attributes, reduced greenhouse gas emissions and superior recyclability. To improve crash worthiness and fuel economy, the automotive industry is, increasingly, using AHSS. Today, and in the future, automotive manufacturers must reduce the overall weight of their cars. The most cost-efficient way to do this is with AHSS. However, there are several parameters that decide which of the AHSS types to be used; the most important parameters are derived from the geometrical form of the component and the selection of forming and blanking methods. This paper describes the different types of AHSS, highlights their advantages for use in auto metal stampings, and discusses about the new challenges faced by stampers, particularly those serving the automotive industry.

PurposeThe purpose of this paper is to study the process, network, skills and practices of service parts logistics organizations in the Asia Pacific region. Specifically, it attempts to propose a new framework for service parts logistics management based on interview inputs from several leading automotive and aerospace companies. This paper also seeks to identify the trends and opportunities for service parts logistics in Singapore.Design/methodology/approachCompanies from aerospace and automotive industries involved in service logistics activities were involved in the study. Data were obtained primarily through interviews with key executives of the company.FindingsThis paper summarizes some of the industry findings on service parts logistics in the Asia Pacific region. To succeed in the service logistics business, companies should not focus on cost factors alone. Instead, companies should adopt the proposed framework and look into other factors.Research limitations/implicationsThe research is limited to companies in the aerospace and automotive industries only.Practical implicationsThis framework was drawn from industry inputs and can be easily applied in decision making.Originality/valueThe paper provides a new framework to assist decision makers in deciding where a company should locate its service part logistics hub.

An all-natural fire-resistant bioinspired cellulose-based structural material by external force-induced assembly

Magnesium is increasingly becoming an attractive alternative to steel, aluminum, and polymer composites for vehicle weight reduction due to its ability to meet vehicle performance requirements. To meet the Corporate Average Fuel Economy (CAFÉ) standard and to maximize the weight reduction of vehicles in the coming years, the magnesium applications are expected to increase significantly in both structural and powertrain components where material creep resistance is required. This first half of the paper will give an overview of recent automotive magnesium R&D programs including Light Metal Cast, Magnesium Powertrain Cast Components, and Structural Cast Magnesium Development supported by the United States Council for Automotive Research (USCAR) and the US Department of Energy. The USCAR is the umbrella organization of DaimlerChrysler Corporation, Ford Motor Company and General Motors, which was formed in 1992 to further strengthen the technology base of the US automotive industry through cooperative, pre-competitive research. During the last decade, the magnesium foundry industry has grown, yet the material and manufacturing process costs of magnesium die-casting has impeded large-scale implementation into the automotive industry. As a result, Ford Motor Company initiated a Cost Reduced Magnesium Die Castings Using Heated Runners (CORMAG) program in partnership of the Advanced Technology Program of the US National Institute of Standards and Technology. The second half of this paper will briefly present the program goal, progress and its impact. In addition, this paper will present some magnesium applications, including a 2004 Ford F-150 light truck Front End Support Assembly and a 2005 Ford GT instrument panel structure.

Mechanical response of composite materials prepared with polyurethane elastomers and polyvinyl chloride films

Tensile and Spring-Back Behavior of DP600 Advanced High Strength Steel at Warm Temperatures