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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Siedlak, Dennis J. L. Schlais, Paul R. Pinon, Olivia J. Mavris, Dimitri N. Georgia Inst Technol Daniel Guggenheim Sch Aerosp Engn Aerosp Syst Design Lab Atlanta GA 30332 USA

ISBN: (纸本)9780791856833

In the years since the Cold War;the aerospace industry has seen a shift towards affordability-based design from the primarily petformance-based designs of the past era. While many techniques, such as IPPD and PLM, have been implemented in support of this shift recent developments in the industry have led to major cost overruns and production delays. the increased prevalence of demand variability in the aerospace industry and the difficulty to rapidly adapt production plans are a primary cause of these issues. Furthermore, traditional aircraft designers perform detailed manufacturing cost analysis late in the design process when the majority of the pro gram costs are already committed. With the recent shift to more composite aerostructures, historical regressions and cost estimating relationships used to predict cost and manufacturability are no longer accurate, so postponing more detailed cost analyses to later design phases can lead to high costs due to sub-optimal early design decisions. the methodology presented in this paper addresses these problems by providing the ability to conduct multi-disciplinary trades in the early stages of design, when a large amount of design freedom and cost savings opportunities exist. To enable these multi-disciplinary trades, this paper describes how aircraft performance considerations are integrated with production rate, manufacturing cost, and financial planning metrics into a parametric, visual trade-off environment. the environment, combined with a multi-objective optimization routine, facilitate effective affordability-based trades during the early stages of design. An F-86 Sabre redesigned wingbox using 3 separate manufacturing concepts is used as a proof-of-concept for this research.

关键词： Cost benefit analysis

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thermal analysis of a Jet Deflector Subjected to Liquid Engine Jet Exhaust in a Static Test

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HEAT TRANSFER engineering 2015年第4期36卷 346-351页

作者： Anoop, Parameswaran Unnikrishnan, Chakkedath Sundar, Balachandran Chacko, M. Joseph VSSC ISRO AERO AHTD Trivandrum 695022 Kerala India

the survivability of a jet deflector encountering severe heating conditions due to the direct impingement of exhaust gases from a liquid engine is analyzed. Using engineering methods the thermal environments and temperature history are estimated. the cooling of the jet deflector using a water stream into the exhaust stream through spray nozzles located upstream from the deflector to reduce the exhaust temperature is considered. Since the major source of heating of the jet deflector is by convection, the convective heating due to jet impingement is evaluated. A flow field from the exhaust of the liquid engine is generated using a finite-volume-based Navier-Stokes computational fluid dynamics solver. For evaluating convective heat transfer coefficient, engineering methods are used based on the flow-field data generated. the theoretical flow-field data generated do not account for jet water mixing. To account for the water jet effect, an energy balance method is used to estimate the jet temperature and a one-dimensional thermal response analysis is carried out using in-house design code. the computed temperature data are compared with the measured temperature data and the survivability of the jet deflector is assured.

关键词： thERMAL analysis MECHANICAL engineering ENGINES TEMPERATURE CALORIMETRY

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Surface Roughness Prediction using Numerical Scheme and Feedback Control

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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Ayomoh, Michael K. O. Abou-El-Hossein, Khaled A. Ghobashi, Sameh F. M. Nelson Mandela Metropolitan Univ Mechatron Engn Dept ZA-6001 Port Elizabeth South Africa

ISBN: (纸本)9780791856826

this paper proposes a numerical modelling scheme for surface roughness prediction. the approach is premised on the use of 3D difference analysis method enhanced with the use of feedback control loop where a set of adaptive weights are generated. the surface roughness values utilized in this paper were adapted from [1]. their experiments were carried out using S55C high carbon steel. A comparison was further carried out between the proposed technique and those utilized in [1]. the experimental design has three cutting parameters namely: depth of cut, feed rate and cutting speed with twenty-seven experimental sample-space. the simulation trials conducted using Matlab software is of two sub-classes namely: prediction of the surface roughness readings for the non-boundary cutting combinations (NBCC) with the aid of the known surface roughness readings of the boundary cutting combinations (BCC). the following simulation involved the use of the predicted outputs from the NBCC to recover the surface roughness readings for the boundary cutting combinations (BCC). the simulation trial for the NBCC attained a state of total stability in the 7th iteration i.e. a point where the actual and desired roughness readings are equal such that error is minimized to zero by using a set of dynamic weights generated in every following simulation trial. A comparative study among the three methods showed that the proposed difference analysis technique with adaptive weight from feedback control produced a much accurate output as against the abductive and regression analysis techniques presented in [1].

关键词： Surface measurement Difference analysis Surface Roughness Mesh analysis Feedback control Adaptive weight Boundary Element

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4D PRINTING: design AND FABRICATION OF 3D SHELL STRUCTURES WIth CURVED SURFACES USING CONTROLLED SELF-FOLDING

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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Deng, Dongping Chen, Yong Univ So Calif Daniel J Epstein Dept Ind & Syst Engn Los Angeles CA 90089 USA

ISBN: (纸本)9780791856826

Self-folding structures such as origami-based structures have been studied by artists, mathematicians and engineers. New applications are emerging in fields such as biomedical and electronics. Self-folding structures can potentially extend three-dimensional (3D) printing into four-dimensional (4D) printing by intelligently designed material distribution in order to achieve controlled shape deformation over time. Traditionally, self-folding structures are folded along pre-defined hinges such that neighboring facets can transform their shapes. In this study, we present a new design and fabrication approach of self-folding structures with no foldable hinges. A significant benefit is its capability in fabricating shapes with smooth curved surfaces. Our self-folding method is based on a thermally responsive mechanism, where a thermal responsive film is used as the active material while another polymer material coated on the film is used as the constraining material. When the structure is heated, the two sides of the film will shrink differently due to the constraining material. Consequently the structure will fold. By changing the constraining patterns and coated material properties, the film can be self-folded into different shapes. three types of folding features are presented in our study. Based on them, an unfolding algorithm is presented for a given shell structure with curved surfaces. theoretical analysis and experimental tests are presented to demonstrate the capability of the self-folding method. Its limitation and future work are also discussed.

关键词： Self-folding 4D printing shell structure Stereolithography

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WEAR MECHANISM analysis OF COATED CARBIDE TOOLS IN HIGH-SPEED MILLING OF TI-6AL-4V ALLOY VIA CROSS-SECTION CHARACTERIZATION OF WORN CUTTING EDGE

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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Li, Anhai Zhao, Jun Lin, Fenghua Shandong Univ Sch Mech Engn MOE Key Lab High Efficiency & Clean Mech Mfg Jinan 250061 Peoples R China Shandong Binzhou Bohai Piston Co Ltd Binzhou 256602 Peoples R China

ISBN: (纸本)9780791856826

Tool wear analysis is essential in high speed machining, especially in the intermittent cutting and milling processes. Analyses of tool wear mechanisms will be beneficial for proposing the suggestions in the tool design process how to enhance the tool material properties to improve the cutting performance and eventually tool life. Wear mechanisms of coated carbide tools in high-speed dry milling of Ti-6Al-4V were assessed by characterization of the cross-section of worn tool cutting edge utilizing scanning electron microscopy, and the element distribution of the worn tool surface was detected by using energy dispersive spectroscopy. Results show that flank wear, chipping and flaking of tool material on the rake face and/or at the nose of tools were the dominant failure modes. And synergistic interaction among coating delamination, erosion wear, adhesion, dissolution-diffusion wear, and thermal-mechanical fatigue wear were the main wear mechanisms analyzed from cross-sectional worn cutting edge. Erosion wear was identified in high speed milling of Titanium alloy and introduced into the wear mechanisms of metal cutting tools. the hydromechanics characteristic of the chips produced in high-speed machining should be responsible for erosion wear of cuttings tools.

关键词： High speed milling Wear Mechanisms Cross-section Characterization Titanium alloy Carbide tool

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analysis OF WELD FORMATION IN MULTILAYER ULTRASONIC METAL WELDING USING HIGH-SPEED IMAGES

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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Lee, S. Shawn Kim, Tae Hyung Hu, S. Jack Cai, Wayne W. Abell, Jeffrey A. Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA Gen Motors R&D Ctr Mfg Syst Res Lab Warren MI USA

ISBN: (纸本)9780791856826

One of the major challenges in manufacturing automotive lithium-ion batteries and battery packs is to achieve consistent weld quality in joining multiple layers of dissimilar materials. While most fusion welding processes face difficulties in such joining, ultrasonic welding stands out as the ideal method. However, inconsistency of weld quality still exists because of limited knowledge on the weld formation through the multiple interfaces. this study aims to establish real-time phenomenological observation on the multilayer ultrasonic welding process by analyzing the vibration behavior of metal layers. Such behavior is characterized by a direct measurement of the lateral displacement of each metal layer using high-speed images. Two different weld tools are used in order to investigate the effect of tool geometry on the weld formation mechanism and the overall joint quality. A series of microscopies and bond density measurements is carried out to validate the observations and hypotheses of those phenomena in multilayer ultrasonic welding. the results of this study enhance the understanding of the ultrasonic welding process of multiple metal sheets and provide insights for optimum tool design to improve the quality of multilayer joints.

关键词： Multilayer Ultrasonic Welding Weld Propagation Mechanism High Speed Images

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EFFECTS OF PROCESS VARIABLES ON EXTRUSION OF CARBON FIBER REINFORCED ABS FILAMENT FOR ADDITIVE MANUFACTURING

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10th asme International Manufacturing Science and engineering conference (MSEC2015)

作者： Hull, Emmett Grove, Weston Zhang, Meng Song, Xiaoxu Pei, Z. J. Cong, Weilong Kansas State Univ Dept Ind & Mfg Syst Engn Manhattan KS 66506 USA Texas Tech Univ Dept Ind Engn Lubbock TX 79409 USA

ISBN: (纸本)9780791856826

Additive manufacturing (3D printing) is a class of manufacturing processes where material is deposited in a layer-by-layer fashion to fabricate a three-dimensional part directly from a computer-aided design (CAD) model. With a current market share of 44%, thermoplastic-based additive manufacturing such as fused deposition modeling (FDM) is a prevailing technology. A preliminary extrusion process is required to produce thermoplastic filaments for use in FDM 3D printers. It is crucial that extruded filament must have constant dimensional accuracy for FDM 3D printers to produce the desired object with precision. In this study, carbon fibers were blended with acrylonitrile butadiene styrene (ABS) thermoplastics to produce carbon fiber reinforced ABS filaments in order to improve the mechanical properties of FDM-printed objects. During filament extrusion, three process variables showed significant effects on filament diameter, expansion percentage, and extrusion rate. these process variables included carbon fiber content, extrusion temperature, and nozzle size. the objective of this study is to test the feasible ranges of these process variables and to investigate their effects on filament extrusion. Results of this study will provide knowledge on quality improvement of carbon fiber reinforced ABS filament extrusion for additive manufacturing.

关键词： 3D printing Additive manufacturing Filament extrusion Fused deposition modeling thermogravimetric analysis (TGA)

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Measurement of Steady-State CHF in Horizontal Channels for Low-Pressure, Low-Flow Conditions

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HEAT TRANSFER engineering 2015年第4期36卷 418-428页

作者： Baburajan, Parackal K. Bisht, Govind Singh Gaikwad, Avinash J. Gupta, Satish K. Prabhu, S. V. Atom Energy Regulatory Board Anushaktinagar India Indian Inst Technol Dept Mech Engn Bombay 400076 Powai India

Experimental investigations on critical heat flux (CHF) are mostly on vertical channels involving high mass fluxes and high system pressures. Reported studies on CHF in horizontal flow channels under low-pressure, low-flow (LPLF) conditions are limited. Understanding CHF is essential in the design and operation of heat exchangers and heat-generating devices including fuel channels of nuclear reactors. the present work investigates CHF in horizontal tubes for low steady flow at atmospheric pressure conditions. Appearance of a "red hot" spot on the test section is considered to be the occurrence of critical heat flux condition in this study. Present data could not be predicted using the reported method of applying a correction factor for the vertical lookup table data. A correlation using the experimental data is developed incorporating the fluid-to-fluid modeling parameters for the prediction of CHF in horizontal channels under LPLF conditions. Numerical study using thermal hydraulic system code RELAP5 suggests liquid film dryout as the mechanism of CHF occurrence in the present investigations.

关键词： HEAT flux HEAT transfer thERMAL analysis PRESSURE FORCE density

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PERFORMANCE AND MOORING analysis OF 10 KW FLOATING DUCT-TYPE TIDAL CURRENT POWER SYSTEM 34

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34th asme International conference on Ocean, Offshore and Arctic engineering (OMAE2015)

作者： Jo, Chul-hee Rho, Yu-ho Goo, Chan-hoe Kim, Do-youb Inha Univ Inchon South Korea

ISBN: (纸本)9780791856574

Recently, focus has been placed on ocean energy resources because environmental concerns regarding the exploitation of hydrocarbons are increasing. Among the various ocean energy sources, tidal current power (TCP) is recognized as the most promising energy source in terms of predictability and reliability. the enormous energy potential in TCP fields has been exploited by installing TCP systems. the flow speed is the most important factor for power estimation of a tidal current power system. the kinetic energy of the flow is proportional to the cube of the flow's velocity, and velocity is a critical variable in the performance of the system. Since the duct can accelerate the flow speed, its use could expand the applicable areas of tidal devices to relatively low velocity sites. the inclined angle of the duct and the shapes of inlet and outlet affect the acceleration rates of the flow inside the duct. To investigate the effects of parameters that increase the flow speed, a series of simulations are performed using the commercial computational fluid dynamics (CMS) code ANSYS-CFX. Experimental investigations were conducted using a circulation water channel (CWC). Also, mooring system concepts are investigated using the commercial mooring analysis software WADAM and. OrcaFlex. Due to other floating structures operating within a limited area, station-keeping is needed in order to keep the motions of the floating duct structures within permissible limits. In this study, methods for optimizing the mooring system of a floating duct-type tidal current power system in shallow water are investigated. Based on the performance and mooring analysis results of the 10 kW floating duct-type TCP system, a new design for a small capacity floating TCP system is introduced.

关键词： Power systems (Machinery) Ducts Mooring Tides

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asme 2012 11th biennial conference on engineering systems design and analysis, ESDA 2012

ASME 2012 11th Biennial Conference on Engineering Systems De...

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asme 2012 11th biennial conference on engineering systems design and analysis, ESDA 2012

ISBN: (纸本)9780791844861

the proceedings contain 386 papers and 1 PowerPoint presentation. the topics discussed include: crack initiation and propagation as part of engineering design;heavy truck 5th wheel modeling techniques in finite element and their effect on stress distribution;modelling local dynamic pressure within inflatable sports balls;first steps in the space separated representation of models defined in complex domains;numerical simulation on the flow pattern in forebay of pumping station;a numerical simulation approach for atmospheric pollution evolution at urban scale to help traffic control decision making;fractal orifices for flowmetering;numerical implementation of higher-order homogenization problems and computation of gradient elasticity coefficients;micromechanical based simulation and experimental approaches in the thermal conductivities assessment of hybrid polymeric composite materials;laser sintering process analysis: application to chromium-cobalt alloys for dental prosthesis production;and knowledge-based automated programming of welding robots for lot-size one products.

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