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Viewing 271 to 300 of 19609
Technical Paper
2014-04-01
Gang Huang, Sriram Sadagopan, Hubert Schreier
Forming limit curve (FLC) and fracture forming limit curve (FFLC) are valuable tools for failure prediction in forming simulation and die try-out in press shops. In this paper, methods are presented to determine FLC and FFLC for sheets of advanced high strength steels (AHSS) using digital image correlation (DIC). Dome tests were conducted on AHSS specimens using DIC system for strain measurement. For generating FLCs, two approaches are introduced to determine the onset of localized necking by analyzing the strain history at critical locations, one of which has been implemented into the commercial DIC software Vic-3D (Correlated Solution inc.). For determination of FFLC, a method for measuring fracture strains based on the strain path evolution is presented. The measured FLCs for several AHSS were compared to the FLCs using ISO 12004-2, and conventional North American experimental measurements and empirical equations. The results of comparison revealed that FLCs using DIC are in good correlation with other existing data, thus validating the presented methodologies.
Technical Paper
2014-04-01
Jianghui Mao, Carlos Engler-Pinto, Xuming Su, Scott Kenningley
In this paper, the cyclic deformation behavior of an Al-Si-Cu alloy is studied under strain-controlled thermo-mechanical loading. Tests are carried out at temperatures from 20 °C to 440 °C. The effect of strain rate, hold time at temperature and loading sequence are investigated at each temperature. The results show that temperature has a significant effect on the cyclic deformation of Al-Si-Cu alloys. With increasing temperature, the effect of strain rate and hold time become more significant, while load sequence effects remain negligible within the investigated temperature range. Thus, an elasto-viscoplastic model is required for modeling the alloy's behavior at high temperature. This study provides an insight into the necessary information required for modeling of automotive engine components operating at elevated temperature.
Technical Paper
2014-04-01
Guowu Shen, Su Xu, Jie Liang, John Sollen
Magnesium alloys are of growing research, development and commercial interest for their lightweight characteristics, notably in the automotive sector. Recent results based on experiments and simulations of beam components have shown that finite element (FE) predictions using commercial FE software may significantly overestimate the peak load and load beyond the peak load. This indicates that better deformation and failure criteria are needed for crashworthiness simulation and design of Mg alloys for the development of computer-assisted engineering (CAE) capacity for Mg alloys. In this study, yield and hardening laws for deformation simulation of Mg alloys are reviewed. An isotropic Lode angle dependent von Mises yield and flow model originally used for soil was modified by replacing shear strength with tensile or compressive flow strength for deformation simulation of Mg alloys. In this law, the yield and strain hardening criteria depend on Lode angle (θ), a parameter related to the stress state of the material, e.g. θ=0corresponds to uniaxial tension and θ=30° corresponds to pure shear.
Technical Paper
2014-04-01
Li Huang, John V. Lasecki, Haiding Guo, Xuming Su
In present paper, the process of joining aluminum alloy 6111T4 and steel HSLA340 sheets by self-piercing riveting (SPR) is studied. The rivet material properties were obtained by inverse modeling approach. Element erosion technique was adopted in the LS-DYNA/explicit analysis for the separation of upper sheet before the rivet penetrates into lower sheet. Maximum shear strain criterion was implemented for material failure after comparing several classic fracture criteria. LS-DYNA/implicit was used for springback analysis following the explicit riveting simulation. Large compressive residual stress was observed near frequent fatigue crack initiation sites, both around vicinity of middle inner wall of rivet shank and upper 6111T4 sheet.
Technical Paper
2014-04-01
Wei-Jen Lai, Shin-Jang Sung, Jwo Pan, Yunan Guo, Xuming Su
Failure mode and fatigue behavior of dissimilar laser welds in lap-shear specimens of aluminum and copper sheets are investigated. Quasi-static tests and fatigue tests of laser-welded lap-shear specimens under different load ranges with the load ratio of 0.1 were conducted. Optical micrographs of the welds after the tests were examined to understand the failure modes of the specimens. For the specimens tested under quasi-static loading conditions, the micrograph indicates that the specimen failed through the fusion zone of the aluminum sheet. For the specimens tested under cyclic loading conditions, two types of failure modes were observed under different load ranges. One failure mode has a kinked crack initiating from the interfacial surface between the aluminum and copper sheets and growing into the aluminum fusion zone at an angle close to 90°. The other failure mode has an interfacial crack initiating at the interfacial surface between the aluminum and copper sheets and growing along the interfacial surface between the fusion zone and the copper base metal at an angle close to 90°.
Technical Paper
2014-04-01
Mersin Hurpekli, Rifat Yilmaz, Emin Kondakci, Nuri Solak
Abstract Honing is a low-speed abrading process to remove metallic and non-metallic materials from a surface. Honing corrects surface errors produced by other machining operations prior to honing. Moreover,, the honing grooves, the volume and the direction of the valleys control the amount of oil available, by keeping the oil on the bore surface and by improving the spreading of the oil. The traditional honing process that uses ceramic abrasives has been replaced by the superior abrasives that is Metal Bonded Diamond [1,2]. However, the main drawback of diamond honing is that it leaves more torn metal and folded metal on surface [3]. The folded and / or torn metal partially covers the honing grooves and interrupts oil flow in groove. Hence, it causes abrasive wear as axial scratches on the cylinder surface. Diamond is the strongest material known that is less friable, wear very little, requires more pressure and tends to plough through metal surface rather than cut. On the other hand, conventional abrasives that are ceramic abrasives have self-sharpening properties and higher friability.
Technical Paper
2014-04-01
Rok Kopun, Dongsheng Zhang, Wilfried Edelbauer, Bernhard Stauder, Branislav Basara, David Greif
In this paper, a recently improved Computational Fluid Dynamics (CFD) methodology for virtual prototyping of the heat treatment of cast aluminum parts, above most of cylinder heads of internal combustion engines (ICE), is presented. The comparison between measurement data and numerical results has been carried out to simulate the real time immersion quenching cooling process of realistic cylinder head structure using the commercial CFD code AVL FIRE®. The Eulerian multi-fluid modeling approach is used to handle the boiling flow and the heat transfer between the heated structure and the sub-cooled liquid. While for the fluid region governing equations are solved for each phase separately, only the energy equation is solved in the solid region. Heat transfer coefficients depend on the boiling regimes which are separated by the Leidenfrost temperature. The objective of the present research work is to present an update of the quenching model where instead of constant, variable Leidenfrost temperature is applied.
Collection
2014-04-01
This technical paper collection advances the knowledge in the state of the art in all types of sheet metal forming. Topics include using simulated, analytical, numerical and experimental tools and sheet metals for the various forming technologies.
Collection
2014-04-01
This technical paper collection includes papers related to welding and joining of similar or dissimilar materials of plastics, composites, aluminum, magnesium, titanium, and conventional and advanced high strength steels. Papers related to friction stir (spot) welding, ultrasonic welding, resistance welding, arc welding, laser welding, brazing or soldering, riveting and bolting, and adhesive joining, strength, fracture and fatigue of welds, joints and fasteners are covered.
Technical Paper
2014-04-01
Takaaki Kondo, Kentarou Ishiuchi
Abstract To reduce the Body in White (BIW) mass, it is necessary to expand the application of Advanced High-Strength Steels (AHSS) to complex shaped parts. In order to apply AHSS to complex shaped parts with thinner gauge, high formability steel is required. However, higher strength steels tend to display lower elongations, compared with low/medium strength steels. Current AHSS are applied to limited parts for this reason. The new 1.2GPa material, with high formability, was developed to solve this issue. The mechanical property targets for the high elongation 1.2GPa material were achieved by precise metallurgical optimization. Many material aspects were studied, such as formability, weldabilty, impact strength, and delayed fracture. As the result of this development, 1.2GPa AHSS has been applied to a new vehicle launched in 2013.The application of this material was the 1st in the world, and achieved a 11kg mass reduction.
Magazine
2014-04-01
Toward smarter manufacturing and materials At the U.K.'s new Advanced Manufacturing Research Center, engineers and innovators have at their disposal some of the world's most advanced design and manufacturing assets for precision engineering. More electric, integrated fuel systems Engine system reliability can be improved by advanced electric architectures, while the reduction of hydraulic components, fuel tubes, and fittings can enhance the maintainability of the engine and minimize pilot workload.
WIP Standard
2014-03-26
This proposed specification aims to cover a new alloy (Ti-54M) in the product form of sheet (<.1875in).
Standard
2014-03-25
The methodology for maximum package size loading is bsed on a mathematical method allowing the calculation of maximum package size tables. This method does not in principal differentiate between bulk loading and cargo system loading. However, some restrictions have to be considered: - Some cargo systems generate pre-determined pallet trajectories. Envelope curves depending on the pallet size and the possible trajectories have to be determined first. - Door geometric limitations (with or without cargo loading system) - Turning limitations due to weight, load geometry and conveyance capability - Securing requirements This document is not intended for airline operational use. It should be used by engineers performing calculations or developing computer programs to produce Maximum Package Size tables specified in AS1825.
Standard
2014-03-25
This SAE Aerospace Recommended Practice (ARP) delineates the minimum operational requirements that will ensure that perishable cargoes in insulated standard airborne containers are kept in prime condition during the ground handling and air transportation cycle for a maximum period of 36 h.
Standard
2014-03-25
The scope of this SAE Aerospace Standard (AS) shall cover the methodology of defining and determining the "internal volumes" of both the main deck and lower deck aircraft cargo compartments. The minimum required clearance between the compartment envelope and the unit load devices (ULDs) shall also be stated in order to provide the maximum ULD external contour and the methodology to define the ULD internal volumes.
Standard
2014-03-25
This SAE Aerospace Standard (AS) establishes the basic requirements for the design, construction and testing of air mode 2.44 m x 2.44 (8 ft X 8 ft) cross-section containers. These containers are to be used exclusively in conjunction with the air mode in freighter versions of wide-body commercial transport aircraft. Air mode containers will normally be on aircraft roller conveying systems and/or on similarly equipped ancillary ground handling devices. Similar requirements for air/surface (intermodal) containers are provided in AS832.
Standard
2014-03-25
This SAE Aerospace Standard (AS) establishes the basic requirements for the specification and testing of air/surface (intermodal) 8 ft x 8 ft (2.44 m x 2.44 m) cross-section containers. The basic rquirements for the air/surface (intermodal) container are presented in Sections 3 to 6 while the detailed design requirements are in Appendix A. Appendix B describes the sections of other standards that apply to air/surface containers. Appendix C describes uniformity of test apparatus and methods. These appendices shall be referred to for important supplemental requirements and procedures for this document. AS4041 presents the requirements for air mode general purpose containers. Requirements for containers to be transported by rotary-wing aircraft are excluded from this document. NOTE: The essential basic and detail criteria are identified by use of the key word "shall." Recommended basic and detail criteria are identified by use of the key word "should," and while notmandatory, are considered to be of primary importance in providing serviceable, economical, and practical air/surface containers.
Article
2014-03-24
The technology organization has developed an innovative process to help reduce the cost of composite component use. Features normally added in a separate operation, such as clips and inserts for threaded fasteners, can now be molded directly onto the back of high-quality composite panels, producing a more cost-effective part than a conventional bonded assembly.
Technical Paper
2014-03-24
Karthikeyan N, Anish Gokhale, Narendra Bansode, Gaurav Lakhe
Abstract Scooters are popular for the legroom available in the front and closed storage space beneath the seat. Engine is located at rear part of the vehicle beneath the storage space and is cooled by forcing the air by a centrifugal fan over the engine surface. Heat is rejected from the engine by the forced cooling and radiation to the surroundings. Storage space gets heated as result of excessive heat rejection from engine. To protect the material of storage space and the items stored in that, it is necessary to avoid heating of the storage space. The work aims to conduct the storage space heating analysis in a scooter. The objective is to propose the design modifications to reduce the storage space heating. The effect of convection and radiation in heating of the storage space is studied. Three dimensional Computational Fluid Dynamics (CFD) analysis, with a commercial code, is carried out to evaluate the heat transfer from the engine to the storage space, this gives a good scope in analyzing the effect of different parameters in avoiding the heating and aids in swift modifications in the design process.
Technical Paper
2014-03-24
Pawut Namklang, Vitoon Uthaisangsuk
Abstract Ultra-High Strength Steels (UHSSs) have been widely used to reduce car body weight and to increase crashworthiness of new generation vehicles. To manufacture such components, hot stamping or press hardening process was developed, in which sheet metal forming at high temperature and quenching procedure were performed successively in a single step. Generally, hot stamped parts exhibit exceptionally high strength properties and low springback effect. In this work, a direct hot stamping process of boron-alloyed steel with a thickness of 1.4 mm was investigated. Temperature evolutions on blank and tools were determined during the experiments. Afterwards, microstructure analysis, hardness measurement and tensile test for different locations, namely, at the bottom and flange of the formed samples were carried out. It was found that final parts after the hot forming mostly showed a fully martensitic microstructure. Yield strength and tensile strength up to 1100 and 1500 MPa, respectively, could be obtained.
Technical Paper
2014-03-24
Daeyong Kim, Hyeon Park, Ji Hoon Kim, Youngseon Lee, Myoung-Gyu Lee
Abstract In this study, numerical simulations of electromagnetic forming (EmF) for automotive sheet metals with flat spiral coil were performed in order to analyze electromagnetic, mechanical behaviors in EmF process. Two automotive sheets which are 5J32 aluminum alloy sheet and DP780 high strength steel sheet having thickness of 1.0mm were utilized. Numerical simulations were conducted with the commercial software LS-Dyna, which is able to fully couple with electromagnetic and mechanical as well as thermal natures in three dimensional spaces. From numerical analysis, electromagnetic quantities such as Lorentz force and mechanical quantities such as deformed shape of sheet metals were examined. At low charge voltage, the simulations of the deformed shape for two workpiece blanks have a good agreement with the experiments.
Technical Paper
2014-03-24
Sang-Woo Kim, Young-Seon Lee
Abstract Recently, the applications of magnesium alloy to automobile and electric parts have been increased because of its high specific strength, excellent machinability, high electrical and thermal conductivity. The efforts of automobile industry to reduce fuel consumption by using lightweight structural materials have accelerated the deep drawing technology of magnesium alloy sheet. In the present study, the basic study to fabricate an automotive compressor case have been carried out. In order to apply ductile fracture criterion to predict the forming failure, critical damage values were determined from uniaxial tensile tests and FE simulations, and then they were expressed as the function of strain rate and temperature. The proposed methodology was applied to design the deep drawing process for fabrication of magnesium automotive compressor case without any defect. Based on the simulation and experimental results, AZ31 EL-cover part 39% lighter than ADC12 die casting EL-cover could be fabricated by warm deep drawing process.
Technical Paper
2014-03-24
Kee-Jin Park, Yong-Sik Kim
Abstract Heat treatment for car body's mold is mainly a manual process which is performed by worker. The performance of this process is affected by workers' skill level, and has limitation to maintain uniform product quality. In this study, we developed high frequency heat treatment robot system that implements OLP type simulator to overcome the limitation of manual process, and to improve and stabilize the quality level. Also, we plan to verify the efficiency of robot system and mechanism stability from the early stage through design verification and simulated analysis in development stage. In addition, we plan to study the way to establish optimized D/B for heat treatment criteria for car body mold such as heat treatment speed, interval, etc. via site experiment.
Standard
2014-03-24
This specification covers methyl alcohol in the form of a liquid.
Standard
2014-03-24
This specification covers a denatured ethyl alcohol in the form of a liquid.
Standard
2014-03-19
This specification covers a titanium alloy in the form of bars, wire, forgings, and flash welded rings 4.000 inches (101.60 mm) and under in nominal diameter or least distance between parallel sides and of stock for forging and flash welded rings.
Standard
2014-03-17
This standard establishes the physical item marking requirements for identificationpurposes for copper and copper-base alloy mill products procured and issued for government activities. Shipment and inspection accpetance markings are not within the scope of this standard.
Standard
2014-03-11
This specification covers a titanium alloy in the form of bars, forgings, and stock for forging.
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