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Viewing 241 to 270 of 19612
Technical Paper
2014-04-01
Debabrata Ghosh, Lokesh Pancholi, Asmita Sathaye
Abstract Use of adhesives in automotive require in-depth material, design, manufacturing & engineering knowledge. It is also necessary to understand functional requirements. For perfect and flawless adhesive joinery, the exact quantity of adhesive, its material composition, thickness of adhesive layer, substrate preparation methods for adhesive bonding, handling and curing time of the adhesive have to be studied & optimized. This paper attempts to describe different aspects of adhesive bonding in automotive industry to include: Selection of adhesives based on application and design of the components, surface preparation of adherend, designing of adhesive joint, curing conditions of adhesives, testing and validation of adhesive joints. Emphasis was given to study & verify the performance of different adhesive joints to meet end product requirements. Samples were prepared with a variety of adhesive and adherend combinations. These combinations were tested for tensile, single lap shear, T-peel, flexural & fatigue tests according to standard testing methods.
Technical Paper
2014-04-01
Seiji Furusako, Kodama Shinji, Yasunobu Miyazaki, Tetsuro Nose, Yoshiaki Akiniwa
To achieve improvement of crashworthiness and weight reduction of car bodies, the application of high strength steel sheets to car bodies is expanding [1, 2]. However cross tension strength of spot welded joints decreases as material strength increases in the range of material strength exceeding 780MPa grade. Therefore arc spot welding was attempted to enhance the joint strength in a high strength steel sheet of 980MPa in tensile strength. Consequently, the following experimental results were obtained: 1) cross tension strength (CTS) of the arc spot welded joints doubled compared with CTS of spot welded joints when appropriate welding conditions such as heat input and hole diameter of the sheet were selected and 2) height of excess weld decay in addition to the diameter of weld metal for the arc spot welded joints played an important role in improving CTS.
Technical Paper
2014-04-01
Rod Emery
Abstract With Battery-free Automated Guided Vehicles (AGVs), the production line is no longer held hostage to a slow station, and diverge/converge paths do not require a coupling/uncoupling process. Asynchronous indexing ensures that units move forward when they are ready, enabling the most efficient production paths. Where overhead conveyance is required for ergonomics or engagement with other line paths, it is easily integrated into the Inductive Power Transfer (IPT®) system. A software and controls-driven conveyance, its integrated intelligence allows for seamless inclusion of automated work instructions, error proofing, traceability, Factory Information Systems (FIS) and other elements of Manufacturing Execution Systems (MES) for improved quality. Requiring only two shallow channels cut into an iron-free floor, path changes are quickly made. Gone are requirements for floor pits and drag chains and for hundreds of highly skilled changeover staff during shut-down. A clean, smooth flat floor free of obstructions, trenches or floor-mounted rails reduces workplace injuries.
Technical Paper
2014-04-01
Sunil Kumar Chippa, Bhavani Srinivasaiah, Samraj Jabez Dhinagar
Abstract Automated testing of manufactured products reduces the lead time to considerable extent in the process of production to delivery. Products like automobiles demand automated testing, for which robots and vision systems are widely employed. The basic functionality of a vision system in automation is to detect an object and then recognize it. In current automotive industry such systems are being used for robotic guidance, component tracking, dimensional gauging etc. There is a need to test the proper functionality of a speedometer fitted on a motorbike in the production line itself. Focused work on detection and recognition of Analog type and Digital type speedometer console reading of a motorbike is described in this paper. A vision based system is proposed which recognizes the speedometer reading instantaneously at the desired time. Image binarization, connected component analysis combined with character recognition algorithms are used to achieve the desired recognition, which resulted in reduced lead time hence contributing to lean manufacturing
Technical Paper
2014-04-01
Fengzhu LI, Shunan Bao, Gang Li
Abstract In order to meet the requirement of Flexible Manufacturing System, tool management, including tool preparation and tool setting, has to be planned systematically at the beginning of manufacturing engineering planning and flexible manufacturing line planning based on lean manufacturing principles. The objective of this article is to study the tool management factors that lean and flexible manufacturing system required, based on the planning of tool management in a new engine factory. This article introduces the main contents of tool management systems, analyzes the process of tool management, and summarizes the steps of tool planning process. In details, this article includes planning on tool management procedures, plant floor layout and information system. In addition, the article puts forwards a formula for calculation of tool presetting time, so that the demand of tool equipment quantity and personnel in a tool presetting room can be decided. This article can be used as reference or assistance to engineers as they develop tool management systems for engine manufacturing systems.
Technical Paper
2014-04-01
Li Yanhua, Jianping Lin
Abstract Similar laser welded blanks with same material and same gauge have been extensive applied in automobile body for improving the material utilization and extending maximum coil size. It is known that, for TWBs with dissimilar material and thicknesses, the difference of material properties and/or thickness of the welded blanks, change of the material properties in the weld seam and heat-affected zones (HAZ) as well as location and orientation of the weld seam are reasons for reduced formability. However, the plastic deformation capacity of TWBs is reduced even when the material and thickness are the same. The aim of this paper is to evaluate the deformation behaviors of similar laser welded joints. Uniaxial tensile of five laser welded joints, with 90°,60°,45°,30°and 0°weld orientations, were tested by using optical measurement-DIC (Digital Image Correlation). Strain /strain ratio distribution and evolution of each joint was analyzed and compared with base material. In addition, mechanical property of weld was determined using rule of mixture and hardness testing.
Technical Paper
2014-04-01
Yi-Hsin Chen, Xu Chen, Nan Xu, Lianxiang Yang
Abstract The residual stresses found in components are mainly due to thermal, mechanical and metallurgical changes of material. The manufacturing processes such as fabrication, assembly, welding, rolling, heat treatment, shot peening etc. generate residual stresses in material. The influence of residual stress can be beneficial or detrimental depending on nature and distribution of the residual stress in material. In general, the compressive residual stress can increase the fatigue life of material because it provides greater resistance for crack initiation and propagation. A significant number of improvements for residual stress measurement techniques have occurred in last few decades. The most popular technique of residual stress measurement is based on the principle of strain gage rosette and hole drilling (ASTM E837-01, destructive). Although this technique is effective for some applications, strain gages provide the localized or averaged data and cannot capture the peak or high resolution data when this technique is applied on high strain gradient areas.
Technical Paper
2014-04-01
Dileep Kumar Gupta, Abhishek Sharma, Varun Pathak, Naveen Kumar
Due to high energy demand and limited availability of fossil fuels, the energy necessity becomes a point of apprehension as it results in hike of fuel prices. It is essential to develop renewable energy resources while considering the impact on environment. In the last decade, demand of alternative fuels has increased a lot. Therefore, researchers have already started working on the aim of developing a green fuel to overcome the future energy demand. And as we know that the biodiesel is generally prepared from the non-edible and renewable resources thus, it can be among the competitive alternative future fuels. Besides that, it does not require any prior engine modifications for its usual advantage among other alternative fuels while using it within certain boundaries. However, the process biodiesel production is in itself time consuming which increases the cost of production while decreasing the yield. Supercritical method is drawing major attention for its efficient means with overcoming the negatives of conventional production processes.
Technical Paper
2014-04-01
Michael D. Kass, Chris Janke, Timothy Theiss, Steve Pawel, James Baustian, Les Wolf, Wolf Koch
The compatibility of plastic materials used in gasoline storage and dispensing applications was determined for test fuels representing neat gasoline (Fuel C), and blends containing 25% ethanol (CE25a), 16% isobutanol (CiBu16a), and 24% isobutanol (CiBu24a). A solubility analysis was also performed and compared to the volume swell results obtained from the test fuel exposures. The plastic specimens were exposed to each test fuel for16 weeks at 60°C. After measuring the wetted volume and hardness, the specimens were dried for 65 hours at 60°C and then remeasured for volume and hardness. Dynamic mechanical analysis (DMA), which measures the storage modulus as a function of temperature, was also performed on the dried specimens to determine the temperature associated with the onset of the glass-to-rubber transition (Tg). For many of the plastic materials, the solubility analysis was able to predict the relative volume swell for each test fuel. Those plastic materials commonly used as permeation barriers exhibited the least amount of volume and hardness change (<5%) when exposed to the test fuels.
Technical Paper
2014-04-01
Dan Kraehling, David Anderson, Michael Worswick, Tim Skszek
Abstract The effect of stress triaxiality on failure strain in as-cast magnesium alloy AM60B is examined. Experiments using one uniaxial and two notched tensile geometries were used to study the effect of stress triaxiality on the quasi-static constitutive response of super vacuum die cast AM60B castings. For all tests, local strains, failure location and specimen elongation were tracked using two-dimensional digital image correlation (DIC) analysis. The uniaxial specimens were tested in two orthogonal directions to determine the anisotropy of the casting. Finite element models were developed to estimate effective plastic strain histories and stress state (triaxiality) as a function of notch severity. It was found that there is minimal, if any, anisotropy present in AM60B castings. Higher stress triaxiality levels caused increases in maximum stress and decreases in elongation and local effective plastic strain at failure. This data will serve as the basis for the development of a damage-based constitutive model.
Technical Paper
2014-04-01
Ram Iyer, Jin Zhou, Li Lu, Jeffrey Webb, Qaiser Khan
Abstract A CAE simulation methodology was developed to predict the warpage and shape deviation from nominal in finished plastic sub-assemblies that are joined using Infra-Red (IR), hot-plate or vibration welding processes. An automotive glove box bin and door sub-assembly was used to develop the methodology. It was seen that part warpage from injection molding and welding causes warpage in final assembled product which results in gaps and the consequent loss in quality of appearance. The CAE simulation methodology included prediction of the part warpage with residual stress from the injection molding process, use the post-molded shape as an initial part condition for the welding process, and simulation of the welding process itself. The welding process simulation included fixturing of the parts in the welding process, localized heating in the case of an IR welding process, fusion of the parts at the weld locations and thermal creep resulting in long term stress and shape relaxation of the part.
Technical Paper
2014-04-01
Josh Mcilvaine, Malika Warner
Abstract Thermoplastic polyesters are widely used in the automotive industry and are the material of choice for many types of electrical and electronic components due to their excellent balance of mechanical and electrical properties. Under certain conditions including elevated temperatures and the presence of high humidity, thermoplastic polyesters such as polybutylene terephthalate (PBT) have the potential to suffer hydrolytic attack. Recognizing the need for standardization, USCAR USCAR (The United States Council for Automotive Research) established component level testing guidelines specific to connectors. In response, many companies developed HR (hydrolysis resistant) PBT resins to help manufactures meet these requirements. As with many additive technologies in plastics, there are trade-offs. In this case, hydrolysis resistance was often improved at the expense of melt viscosity stability and high flow during the injection molding process. In addition to improved hydrolysis resistance, there is an emerging need for PBT with improved electrical performance for use in automotive connectors for electric hybrid vehicles.
Technical Paper
2014-04-01
Keisuke Kojima, Takeshi Ogawa
Abstract The CO2 emission from automobile plants is large. A majority of this quantity comes from the body painting process. A breakdown of CO2 emissions from the painting process shows the significant impact of painting process equipment such as the oven used to cure paint and the air conditioning facilities used to maintain controlled temperature and humidity on CO2 emissions. It was concluded, therefore, that shortening these processes will effectively promote the reduction of CO2 emissions. Removing the primer process means that the basecoat (BC) and clearcoat (CC), which provide color and marketability, would be applied on the E-coat directly. By the removing the primer several issues are raised such as stone chipping resistance, weather durability, color variation and appearance. By contrast, this 3Wet painting system applies two coats of waterborne basecoat, dividing it up into 1-Base and 2-Base and then CC, in order to achieve both targets, quality and color variation. For severe corrosion areas, chipping primer (CP) is applied to keep chipping resistance before the application of 1-Base.
Technical Paper
2014-04-01
Yanhua Shen, Chun Jin
Abstract The large power mining dump truck usually has electric drive system for the harsh operating conditions of mining. The traction motor and multi-stage reducer are assembled in the limited space of the two rear wheels. The permanent magnet motor is often used as traction motor for its much advantage characteristic. However, the permanent magnet is particularly sensitive to the high temperatures since it can loose a part of magnetization when it is exposed to a high temperature. It is necessary to have better cooling system for improvement thermal performance of permanent magnet (PM) motor. The heat losses generated by permanent magnet motor in the off-road electric driving truck are cooled by the water to maintain the motor working effectively. This paper is focus on analyzing the thermal behavior of the PM motor numerically and experimentally. The 2-D transient temperature field of motor is investigated based on different losses of the permanent magnet motor which is determined by the magnetic field analysis.
Technical Paper
2014-04-01
Yu Hsien Wu, Sreekanth Surapaneni, Kumar Srinivasan, Paul Stibich
Abstract Automotive vehicle body electrophoretic (e-coat) and paint application has a high degree of complexity and expense in vehicle assembly. These steps involve coating and painting the vehicle body. Each step has multiple coatings and a curing process of the body in an oven. Two types of heating methods, radiation and convection, are used in the ovens to cure coatings and paints during the process. During heating stage in the oven, the vehicle body has large thermal stresses due to thermal expansion. These stresses may cause permanent deformation and weld/joint failure. Body panel deformation and joint failure can be predicted by using structural analysis with component surface temperature distribution. The prediction will avoid late and costly changes to the vehicle design. The temperature profiles on the vehicle components are the key boundary conditions used to perform structure analysis. This paper presents an efficient method to predict vehicle body temperature profiles as the vehicle pass through the radiant section of an e-coat and/or paint oven.
Technical Paper
2014-04-01
Philip S. Blackwelder, William Chang, Jonathan Lohr
Abstract The latest generation of Computer Numerically Controlled (CNC) technology enables cost and time effective product development by minimizing the time and expertise required to fabricate precision parts. The North Carolina State University (NCSU) EcoCAR 2 team used specialized Computer Aided Design (CAD) techniques and a CNC water-jet to produce a mounting system to install a custom series-hybrid drivetrain into a 2013 Chevrolet Malibu. The team of engineering students was able to overcome a lack of resources and machining experience by leveraging the capabilities of CAD and CNC to create quality components. Complex 3D designs were broken down into 2D shapes that were precision cut from inexpensive metal plate. The design of these parts featured slot and tab interfaces that enabled parts to be self-locating and were implemented in a way that only allowed parts to be assembled in the correct orientation. The precision fit afforded by the water-jet had the additional benefit of simplifying the welding process by eliminating the need for external work holding.
Technical Paper
2014-04-01
Bartosz Flekiewicz, Marek Flekiewicz
Paper describes analysis of the design process of modern automotive LPG and CNG containers. Over decade experience in the field of both computer based analysis as well as in the real conditions testing has been collected and presented in the paper. Authors present the potentials of modern FEM methodologies in the optimization and production of lightweight steel containers. It has been proved that the most sophisticated numerical analysis have to be followed by the construction verification, particularly considering direct exposure to fire. Bonfire test have become obligatory for both liquid and compressed gases containers. Properly chosen fire protection system, together with the adequate level of quality of materials applied for its production together with proper directing of the gas flowing out from safety devices are the essential factors defining gas containers fire safety. The experience in the field of bonfire tests made it also possible to present the main issues of the proper couplings of containers with their equipment (valves).
Technical Paper
2014-04-01
Paul R. Stibich, Yu Hsien Wu, Weidong Zhang, Michao Guo, Kumar Srinivasan, Sreekanth Surapaneni
Abstract This paper describes a comprehensive methodology for the simulation of vehicle body panel buckling in an electrophoretic coat (electro-coat or e-coat) and/or paint oven environment. The simulation couples computational heat transfer analysis and structural analysis. Heat transfer analysis is used to predict temperature distribution throughout a vehicle body in curing ovens. The vehicle body temperature profile from the heat transfer analysis is applied as an input for a structural analysis to predict buckling. This study is focused on the radiant section of the curing ovens. The radiant section of the oven has the largest temperature gradients within the body structure. This methodology couples a fully transient thermal analysis to simulate the structure through the electro-coat and paint curing environments with a structural, buckling analysis. The ability to predict the buckling phenomenon using a virtual simulation will reduce the risk of late production changes to the vehicle class “A” surfaces.
Technical Paper
2014-04-01
Shailesh Mani Pandey, Qasim Murtaza, Kalpana Gupta
Abstract The functions of a piston ring are to seal off the combustion pressure, to distribute and control the oil, to transfer heat and to stabilize the piston. Most piston rings and metallic sealing rings for modern application where running conditions are severe, require some form of coating to minimise abrasion and corrosion. The piston ring coating improves the life of engine as well as fuel efficiency. In this study, physical vapour deposition (ion chrome plating) was investigated; plates with similar composition as the piston ring material were prepared by the casting process using induction arc furnace and sand mould. Wear test of the coating was conducted on pin on disc machine under dry conditions. The wear rate was calculated using mass loss methods on an electronic balance having least count of 1× 10−4 g. The wear rate of the coating was found to be increased with increase in load as well as sliding speed for the ion plating with the counter body of tungsten carbide but in the case of ion plating with the HCS & MS it is found to be decreased.
Technical Paper
2014-04-01
Kambiz Jahani, Sajjad Beigmoradi, Mohsen Bayani Khaknejad
Abstract The main objective of this study is to investigate the effect of spot-weld modeling approaches on NVH virtual simulation problems. For this purpose, finite element method is considered for further simulations. The goal is to evaluate and compare results within the domain of 0 to 200 Hz by modeling spot-welds with three different element types: a rigid body constraint element (RBE), two rigid body elements with hexahedral solid element (RBE3-HEXA-RBE3) and CWELD constraint. In order to evaluate the effects, three main NVH analyses are chosen for this study. In the first place, a free-free modal analysis is performed for the BIW and trimmed body models of a D-segment saloon car in order to estimate natural frequencies and mode shapes. Afterwards, a frequency response analysis is performed to evaluate the dynamic stiffness of engine mount. Finally, a noise transfer function (NTF) simulation is carried out to calculate the sound pressure level at driver ear's location. The out coming results from each type of simulations are extracted and compared to investigate the effect of spot-weld modeling on the accuracy of FEM analyses results concerning NVH problems.
Technical Paper
2014-04-01
Ould Mohamed Lemine Yahya, Houssem Eddine Miled
Abstract The ultrasonic (US) welding of wires in automotive harnesses is increasingly used as an alternative to mechanical splices. However, this welding process may harm the electrical terminals crimped on the wires ends as a result on the energy propagation along the wire up the terminal with a frequency that is close to the terminals' natural frequencies. The modeling of the ultrasonic welding had been investigated by several authors from the process and weld strength perspective but the modeling of its effect on electrical terminals in automotive harnesses has not been given much attention in the literature. This paper describes and illustrates approaches used for modeling of the impact of the US welding on the electrical terminals in terms of stress and deformation from qualitative and quantitative perspectives and the related benefits/limitations from predictive standpoint. Illustrations are given on an actual terminal with respect to a typical ultrasonic welding process.
Technical Paper
2014-04-01
Ramya Natarajan, Ganesan Swaminathan, Shanmugasundaram Ramanathan
Abstract The machine breakdown occurrences in the shop floor of the manufacturing facilities of Ashok Leyland, were captured into the Enterprise Resource Planning (ERP) system with significant time delay. This affected the overall productivity of the shop floor lines. Hence, there was a need to deploy a computer based application with a simple Graphical User Interface (GUI) in the shop floor, to capture breakdown and update the ERP system accordingly. This application was meant for use by the shop floor associates, who come to know of the machine breakdown occurrences first. Also, there was a need for the managers at various levels to monitor the breakdowns, to ensure their timely closure. To fulfil these requirements, the in-house IT resources were sought after by the plant maintenance group. Free and Open Source Software (FOSS) was identified for application development and deployment. FOSS aids in significant cost savings, as there is no license cost involved in application development.
Technical Paper
2014-04-01
Yaamini Devi Loganathan, Jayakrishnan M
Abstract The automobile industry in India has long been recognized as a core manufacturing sector with the potential to drive national economic growth. India's attraction as a destination for automobile manufacturers has been underscored by the number of new manufacturers entering the country over the last two decades, through FDI. The number of manufacturers has continued to grow in India over the years across vehicle segments. Multinational and Transnational firms may enter a market by different modes of Foreign Direct Investment (FDI), either by Greenfield, Mergers & Acquisitions, Joint Ventures or Contract manufacturing. Indian automobile industry currently has a wide mix of home grown automobile companies and foreign invested companies. In this FDI development and the inclusion of more automobile manufacturers, the product development process of companies also has gone through a change. The cross pollination of product development process has happened between the automobile manufacturing firms.
Technical Paper
2014-04-01
Bert Bras, Andrew Carlile, Thomas Niemann, Sherry Mueller, Hyung Chul Kim, Timothy Wallington, Heidi McKenzie, Susan Rokosz
Abstract Tools are now publicly available that can potentially help a company assess the impact of its water use and risks in relation to their global operations and supply chains. In this paper we describe a comparative analysis of two publicly available tools, specifically the WWF/DEG Water Risk Filter and the WBCSD Global Water Tool that are used to measure the water impact and risk indicators for industrial facilities. By analyzing the risk assessments calculated by these tools for different scenarios that include varying facilities from different industries, one can better gauge the similarities and differences between these water strategy tools. Several scenarios were evaluated using the water tools, and the results are compared and contrasted. As will be shown, the results can vary significantly.
Technical Paper
2014-04-01
Jiangong Zhu, Zechang Sun, Xuezhe Wei, Haifeng Dai, Hongzhang Cen
Abstract This paper presents a three-dimensional electrochemical electrode plate pair model to study the effect of the electrode tabs configuration. Understanding the distribution of current density, potential and heat generation rate is critical for designing li-ion batteries and conducting effective design optimization studies. We developed several electrode plate pair models which were different in position and size of tabs. Results showed the influence and comparison of different configuration on the distribution of current density, potential density and heat generation rate at different discharge process. The distribution was predicted as a function of tabs. It can provide a theoretical basis for improving battery thermal performance and cooling system design.
Technical Paper
2014-04-01
Patrick Garcia, Sandro Paparelli
Abstract and Introduction After having successfully implemented Lean in Tenneco's Clean Air division, Tenneco Europe decided to expand Lean to its other divisions - Ride Performance including Aftermarket in 2011. These divisions were able to fully benefit from the best practices developed over the last 10 years. The implementation was articulated around two major axes: the execution of complex projects related to processes including several functions and sites. This approach allowed us to reach a critical mass in a reasonable time within the different functions and sites; the execution of smaller projects focused on one specific function,e.g.: Engineering or Sales. This approach is complementary to the first one since it enhances the spread of the lean spirit within the organization. This paper focuses on Tenneco's Ride Performance division and is split into two parts. Part 1 explains: the different steps required to implement the lean mindset; the challenges to implement it, i.e: the continuous improvement cycle, the enabling bureaucracy, the way of spreading the lean within an organization, the balance of top down and bottom up, the methodologies and ways of converting the benefits into concrete results.
Technical Paper
2014-04-01
Pierre Marquette, Arnaud Dereims, Michael Hugon, Guenael Esnault, Anthony Pickett, Dimitrios Karagiannis, Apostolos Gkinosatis
Abstract Today, LRI is a proven manufacturing technology for both small and large scale structures (e.g. sailboats) where, in most cases, experience and limited prototype experimentation is sufficient to get a satisfactory design. However, large scale aerospace (and other) structures require reproducible, high quality, defect free parts, with excellent mechanical performance. This requires precise control and knowledge of the preforming (draping and manufacture of the composite fabric preforms), their assembly and the resin infusion. The INFUCOMP project is a multi-disciplinary research project to develop necessary Computer Aided Engineering (CAE) tools for all stages of the LRI manufacturing process. An ambitious set of developments have been undertaken that build on existing capabilities of leading drape and infusion simulation codes available today. Currently the codes are only accurate for simple drape problems and infusion analysis of RTM parts using matched metal molds. Furthermore, full chaining of the CAE solution will allow results from materials modeling, drape, assembly, infusion and final part mechanical performance to be used in subsequent analyses.
Technical Paper
2014-04-01
Jianghui Mao, Sayed Nassar
Abstract In this paper, experimental study and FEA simulation are performed to investigate the effect of three different methods for joining dissimilar metal coupons in terms of their strength and load transferring capacity. The joining techniques considered include adhesive bonding, bolting and hybrid bolting-and-bonding. Elastic-plastic material model with damage consideration is used for each of the joint components. Traction-separation rule and failure criterion is defined for adhesive. Load transfer capacity and the failure mode are assessed for each type of joining. Joint strength is examined in terms of the effects of adhesive property, bolt preload level, and friction coefficient. Results show that load transferred and failure mechanism vary significantly between samples with different joint methods; preload evolution in bolt changes with friction coefficient; hybrid joint generally has advantage over the other two methods, namely, bolting-only and bonding-only. With appropriate damage model, the FEA could successfully simulate the actual failure mode of the single slap joint samples.
Technical Paper
2014-04-01
Peter J. Ulintz
Abstract The application of advanced high-strength steels with ultimate tensile strengths of approximately 800 MPa is now well established within the automotive stamping industry. Current trends point to growth in higher strength applications with tensile strengths exceeding 1200 MPa. Due to their higher strength and greater springback after forming, producing high-strength steel stampings and their tools requires special attention. Effective processing methods are required that address problems specific to these materials, including: selection of an optimum stamping process and related equipment, solving formability problems, controlling springback, and selecting appropriate die steels and coatings for optimal tool life. As automakers strive to meet 2025 CAFÉ requirements of 54.5 miles per gallon, the demand for higher strength steel stampings will increase among lower tier automotive suppliers. These companies tend to be contract manufacturers and tool & die shops that are well established and experienced with mild steel and high strength low alloy materials.
Technical Paper
2014-04-01
Lei Liu, Zhiheng Yang, Bo Song, Zhengwei Fan, Jianhua Jiang
Ti-alloy sheet is a high-modulus elastic-plastic material, about which the resilience in the cold-forming process is quite difficult to control. As a matter of fact, the procedure of cold-forming is composed of many cases such as tensile case and bending case. An expression of ultimate radius for bending-curvature is obtained based on tri-parameters elastic-plastic constitutive model. By classifying the cold-forming process, some typical cases of cold-forming are presented in this paper, and analytical solutions with a high precision of resilience for high-modulus elastic-plastic material such as Ti-alloy sheet under the different typical cases are obtained in this paper. The accurate analytical solutions of resilience for high-modulus elastic-plastic material presented in this paper will contribute to cold-forming process both in the mould-designing and optimizing of cold-forming procedure.
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