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Viewing 31 to 60 of 19916
2015-04-14
Journal Article
2015-01-0435
S. Khodaygan, M. Hafezipour
Abstract Kinematic accuracy of the robot end-effector is decreased by many uncertainties. In order to design and manufacture robots with high accuracy, it is essential to know the effects of these uncertainties on the motion of robots. Uncertainty analysis is a useful method which can estimate deviations from desired path in robots caused by uncertainties. This paper presents an applied formulation based on Direct Linearization Method (DLM), for 3D statistical uncertainty analysis of open- loop mechanisms and robots. The maximum normal and parallel components of the position error on the end-effector path are introduced. In this paper, uncertainty effects of both linear and angular variations in performance of spatial open-loop mechanisms and robots are considered.
2015-04-14
Journal Article
2015-01-0518
Hirokuni Fuchigami
Abstract In this research, a new wire material made using surface-reforming heat treatment was developed in order to enhance the corrosion fatigue resistance of suspension springs. The aim of surface reforming is to improve hydrogen embrittlement characteristics through grain refinement and to improve crack propagation resistance by partial softening of hardness. The grain refinement method used an α'→γ reversed transformation by rapid short-term heating in repeated induction heating and quenching (R-IHQ) to refine the crystal grain size of SAE 9254 steel spring wire to 4 μm or less. In order to simultaneously improve the fatigue crack propagation characteristics, the possibility of reducing the hardness immediately below the spring surface layer was also examined. By applying contour hardening in the second IHQ cycle, a heat affected zone (HAZ) is obtained immediately below the surface.
2015-04-14
Journal Article
2015-01-0519
Susumu Maeda, Atsushi Kobayashi, Yuichiro Shimizu, Masao Kanayama, Masato Yuya, Hideki Imataka
Abstract A new nitriding technology and material technology have been developed to increase the strength of microalloyed gears. The developed nitriding technology makes it possible to freely select the phase composition of the nitride compound layer by controlling the treatment atmosphere. The treatment environment is controlled to exclude sources of supply of [C], and H2 is applied as the carrier gas. This has made it possible to control the forward reaction that decomposes NH3, helping to enable the stable precipitation of γ′-phase, which offers excellent peeling resistance. A material optimized for the new nitriding technology was also developed. The new material is a low-carbon alloy steel that makes it possible to minimize the difference in hardness between the compound layer and the substrate directly below it, and is resistant to decline in internal hardness due to aging precipitation in the temperature range used in the nitriding treatment.
2015-04-14
Journal Article
2015-01-0525
Constantin Chiriac, Ming F. Shi
Abstract Automotive structural parts made out of Advanced High Strength Steel (AHSS) are often produced in a multistage forming process using progressive dies or transfer dies. During each forming stage the steel is subjected to work hardening, which affects the formability of the steel in the subsequent forming operation. Edge flanging and in-plane edge stretching operations are forming modes that are typically employed in the last stage of the multistage forming processes. In this study, the multistage forming process was simulated by pre-straining a DP980 steel in a biaxial strain path with various strain levels followed by edge flanging and in-plane edge stretching. The biaxial prestrains were obtained using the Marciniak stretch test and edge flanging and in-plane edge stretching were accomplished by the hole expansion test using a flat punch and a conical punch, respectively.
2015-04-14
Journal Article
2015-01-0522
Robert Cryderman, Danielle Rickert, Kelly Puzak, John Speer, David Matlock, Michael Burnett
Abstract Fracture split forged steel connecting rods are utilized in many new high performance automotive engines to increase durability. Higher strength levels are needed as the power density increases. Fracture splitting without plastic deformation is necessary for manufacturability. Metallurgical design is a key for achieving the required performance levels. Several medium carbon steels containing 0.07 wt pct P, 0.06 wt pct S and various amounts of Mn, Si, V, and N were produced by vacuum induction melting laboratory heats and hot working the cast ingots into plates. The plates were cooled at varying rates to simulate typical cooling methods after forging. Microstructures were generally ferrite and pearlite as evaluated by light optical and scanning electron microscopy. Mechanical properties were determined by standard tensile tests, high strain rate notched tensile tests, and Charpy V-notch impact tests to assess “splittability”.
2015-04-14
Journal Article
2015-01-0510
Joy Hines Forsmark, Zachary Dowling, Kelsey Gibson, Caroline Mueller, Larry Godlewski, Jacob Zindel, James Boileau
Abstract Magnesium die-cast alloys are known to have a layered microstructure composed of: (1) An outer skin layer characterized by a refined microstructure that is relatively defect-free; and (2) A “core” (interior) layer with a coarser microstructure having a higher concentration of features such as porosity and externally solidified grains (ESGs). Because of the difference in microstructural features, it has been long suggested that removal of the surface layer by machining could result in reduced mechanical properties in tested tensile samples. To examine the influence of the skin layer on the mechanical properties, a series of round tensile bars of varying diameters were die-cast in a specially-designed mold using the AM60 Mg alloy. A select number of the samples were machined to different final diameters. Subsequently, all of the samples (as-cast as well as machined) were tested in tension.
2015-04-14
Journal Article
2015-01-0514
Sugrib K. Shaha, Frank Czerwinski, Wojciech Kasprzak, Jacob Friedman, Daolun Chen
Abstract The uniaxial compression test was used to assess the influence of strain amount on the behavior of precipitates and texture of the Al-7%Si-1%Cu-0.5%Mg alloy, modified with micro-additions of V, Zr and Ti. As revealed through metallographic examinations, fracturing and re-orientation of the second-phase particles increased with increasing compression strain. However, the intermetallic particles experienced substantially more frequent cracking than the eutectic silicon. The crystallographic texture was measured and correlated with deformation behavior of the alloy. The weak texture of 11<211> and 111<110> components, detected after casting transformed to a mixture of 1<110>, 112<110> and 111<110> components after room-temperature compression deformation. The intensity of the texture components depended on the strain amount. It is concluded that the texture formation in the studied alloy is controlled by the precipitates formed during solidification of the alloy.
2015-04-14
Journal Article
2015-01-0512
Anthony D. Prescenzi
Abstract Ablation casting is an emerging technology which combines traditional sand molding techniques with rapid cooling due to the use of a water soluble binder. High cooling rates and control of solidification direction allows for exceptional mechanical properties and complex shapes. Through the use of ablation, six different body node castings have been manufactured for the 2016 NSX aluminum space frame. The high mechanical properties allowed these castings to be integrated into the crash structure for energy absorption. Using the traditional casting alloy A356, target mechanical properties were 190 Mpa Yield Strength, 280 Mpa Tensile Strength and 12% min elongation. The high elongation was achieved due to the refined eutectic microstructure produced by high cooling rates. The eutectic microstructure produced by ablation was found to be Level 5 or 6 on the AFS scale. Light weighting could also be achieved when compared to traditional GDC castings.
2015-04-14
Journal Article
2015-01-0537
Hong Tae Kang, Abolhassan Khosrovaneh, Xuming Su, Yung-Li Lee, Mingchao Guo, Chonghua Jiang, Zhen Li
Abstract Due to magnesium alloy's poor weldability, other joining techniques such as laser assisted self-piercing rivet (LSPR) are used for joining magnesium alloys. This research investigates the fatigue performance of LSPR for magnesium alloys including AZ31 and AM60. Tensile-shear and coach peel specimens for AZ31 and AM60 were fabricated and tested for understanding joint fatigue performance. A structural stress - life (S-N) method was used to develop the fatigue parameters from load-life test results. In order to validate this approach, test results from multijoint specimens were compared with the predicted fatigue results of these specimens using the structural stress method. The fatigue results predicted using the structural stress method correlate well with the test results.
2015-04-14
Journal Article
2015-01-0530
Mikko Joonas Kähkönen, Emmanuel De Moor, John Speer, Grant Thomas
Abstract Quenching and partitioning (Q&P) is a novel heat treatment to produce third generation advanced high-strength steels (AHSS). The influence of carbon on mechanical properties of Q&P treated CMnSi-steels was studied using 0.3C-1.5Mn-1.5Si and 0.4C-1.5Mn-1.5Si alloys. Full austenitization followed by two-step Q&P treatments were conducted using varying partitioning times and a fixed partitioning temperature of 400 °C. The results were compared to literature data for 0.2C-1.6Mn-1.6Si, 0.2-3Mn-1.6Si and 0.3-3Mn-1.6Si Q&P treated steels. The comparison showed that increasing the carbon content from 0.2 to 0.4 wt pct increased the ultimate tensile strength by 140 MPa per 0.1 wt pct C up to 1611 MPa without significantly decreasing ductility for the partitioning conditions used. Increased alloy carbon content did not substantially increase the retained austenite fractions.
2015-04-14
Journal Article
2015-01-0604
Jibrin Sule, Supriyo Ganguly
Abstract In a multi-pass weld, the development of residual stress to a large extent depends on the response of the weld metal, heat affected zone and parent material to complex thermo-mechanical cycles during welding. Previous investigations on this subject mostly focused on mechanical tensioning or heat treatment to modify the residual stress distribution in and around the weld. In this research, microstructural refinement with modification of residual stress state was attempted by applying post weld cold rolling followed by laser processing. The hardening of the weld metal was evaluated after welding, post weld cold rolling and post weld cold rolling followed by laser processing. The residual stress was determined non-destructively by using neutron diffraction. Hardness results showed evidence of plastic deformation up to 4 mm below the weld surface.
2015-04-14
Journal Article
2015-01-0602
Shin-Jang Sung, Jwo Pan, Mohammed Yusuf Ali, Jagadish Sorab, Cagri Sever
Abstract In this paper, the evolution equation for the active yield surface during the unloading/reloading process based on the pressure-sensitive Drucker-Prager yield function and a recently developed anisotropic hardening rule with a non-associated flow rule is first presented. A user material subroutine based on the anisotropic hardening rule and the constitutive relation was written and implemented into the commercial finite element program ABAQUS. A two-dimensional plane strain finite element analysis of a crankshaft section under fillet rolling was conducted. After the release of the roller, the magnitude of the compressive residual hoop stress for the material with consideration of pressure sensitivity typically for cast irons is smaller than that without consideration of pressure sensitivity.
2015-04-14
Journal Article
2015-01-0706
Zheng-Ming Su, Pai-Chen Lin, Wei-Jen Lai, Jwo Pan
Abstract In this paper, failure modes of dissimilar laser welds in lap-shear specimens of low carbon steel and high strength low alloy (HSLA) steel sheets are investigated based on experimental observations. Micro-hardness tests across the weld zones of dissimilar laser welds were conducted. The hardness values of the fusion zones and heat affected zones are significantly higher than those of the base metals. The fatigue lives and the corresponding failure modes of laser welds as functions of the load ranges are then examined. Optical micrographs of the laser welds before and after failure under quasi-static and cyclic loading conditions are then examined. The failure modes and fatigue behaviors of the laser welds under different loading conditions are different. Under quasi-static loading conditions, a necking failure occurred in the upper low carbon steel sheet far away from the laser weld.
2015-04-14
Journal Article
2015-01-0708
Catherine M. Amodeo, Jwo Pan
Abstract In this paper, mode I and mode II stress intensity factor solutions for gas metal arc welds in single lap-shear specimens are investigated by the analytical stress intensity factor solutions and by finite element analyses. Finite element analyses were carried out in order to obtain the computational stress intensity factor solutions for both realistic and idealized weld geometries. The computational results indicate that the stress intensity factor solutions for the realistic welds are lower than the analytical solutions for the idealized weld geometry. The computational results can be used for the estimation of fatigue lives in a fatigue crack growth model under mixed mode loading conditions for gas metal arc welds.
2015-04-14
Technical Paper
2015-01-0598
Xiaona Li, Changqing Du, Yongjun Zhou, Xin Xie, Xu Chen, Yaqian Zheng, Thomas Ankofski, Rodrigue Narainen, Cedric Xia, Thomas Stoughton, Lianxiang Yang
Abstract Accurate determination of the forming limit strain of aluminum sheet metal is an important topic which has not been fully solved by industry. Also, the effects of draw beads (enhanced forming limit behaviors), normally reported on steel sheet metals, on aluminum sheet metal is not fully understood. This paper introduces an experimental study on draw bead effects on aluminum sheet metals by measuring the forming limit strain zero (FLD0) of the sheet metal. Two kinds of aluminum, AL 6016-T4 and AL 5754-0, are used. Virgin material, 40% draw bead material and 60% draw bead material conditions are tested for each kind of aluminum. Marciniak punch tests were performed to create a plane strain condition. A dual camera Digital Image Correlation (DIC) system was used to record and measure the deformation distribution history during the punch test. The on-set necking timing is determined directly from surface shape change. The FLD0 of each test situation is reported in this article.
2015-03-27
Standard
J2130/1_201503
This SAE Standard applies to all self-propelled machines with a gross vehicle mass greater than 5000 kg that are utilized to clean material from highways, parking lots, airfield runways, outside paved areas that are principally exposed to vehicular traffic. These machines can also be involved with road construction or repaving work. Primary methods for material removal and cleaning can be by mechanical, pneumatic, washing and flushing systems, or in a combination of any system.
2015-03-27
Standard
J1254_201503
This SAE Standard includes names of major components and parts peculiar to this type of machine. Illustrations used here are not intended to include all existing commercial machines or be exactly descriptive of any particular machine. They have been provided to describe the principles to be used in applying this document.
2015-03-27
Standard
J2129_201503
This SAE Information Report lists the method which outside sources will follow when submitting documents for origination or review by the SAE CONAG Council.
2015-03-27
WIP Standard
J2130/2_201503
This SAE Standard applies to all self-propelled machines with a gross vehicle mass up to 5000 kg that are utilized to clean material from outside paved areas, parkland, floors in non-residential buildings and areas principally exposed to pedestrian traffic. Primary methods for material removal can be by mechanical, pneumatic, washing and flushing systems, or in a combination of any system.
2015-03-25
WIP Standard
AMS4871H
This specification covers an aluminum bronze alloy in the form of centrifugal and chill castings.
2015-03-24
Article
Aerojet Rocketdyne recently completed a series of hot-fire tests of additive manufactured components for its AR1 booster engine at its Sacramento test facility.
2015-03-24
Article
The EFC 3600 variable frequency drive from Bosch Rexroth offers a solution for efficient process control application.
2015-03-24
Standard
AMS5629G
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, flash welded rings, extrusions, and stock for forging, flash welded rings, or extrusion.
2015-03-24
Standard
AMS4904C
This specification covers a titanium alloy in the form of sheet, strip, and plate up through 2.000 inches (50.80 mm), inclusive.
2015-03-24
Standard
AMS4115J
This specification covers an aluminum alloy in the form of rolled or cold-finished bars, rods, and wire, of flash welded rings, and of stock for flash welded rings.
2015-03-24
Standard
AMS4116J
This specification covers an aluminum alloy in the form of bars, rods, and wire.
2015-03-24
Standard
AMS4903C
This specification covers a titanium alloy in the form of sheet strip, and plate up through 2.000 inches (50.80 mm), inclusive.
2015-03-24
Standard
AMS4117K
This specification covers an aluminum alloy in the form of rolled or cold-finished bars, rods, and wire and of flash welded rings and stock for flash welded rings.
2015-03-24
Standard
AMS4901T
This specification covers one grade of commercially-pure titanium in the form of sheet, strip, and plate up through 1.000 inch (25.40 mm), inclusive.
2015-03-23
Article
The company has expanded its additive manufacturing material capabilities to support metal 3-D printing of complex high-hardness parts and the ability to customize properties layer-by-layer through “gradient material design.”
Viewing 31 to 60 of 19916

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