Friction characterization and application to warm forming of a high strength 7000-series aluminum sheet

Noder, Jacqueline; George, Ryan; Butcher, Cliff; Worswick, Michael J.

doi:10.1016/j.jmatprotec.2021.117066

Cited by 18 publications

(12 citation statements)

References 27 publications

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“…Since frictional conditions affect the material flow behavior in a forming operation and thus affect the accuracy of model predictions, the tribological response of the 3rd Gen steel and the 590R at room temperature was studied in the Twist Compression Test (TCT) of Schey [ 39 ]. A recent study of Noder et al [ 40 ] on aluminum alloys showed that good correlations between the TCT and forming operations could be established if the TCT process parameters were carefully selected. A schematic of the test methodology is depicted in Figure 19 a.…”

Section: Friction Characterizationmentioning

confidence: 99%

“…The frictional torque is measured with the aid of a 45 N-load cell positioned in the torque arm. For details on the test apparatus, the reader is referred to Noder et al [ 40 ]. The process parameters of the friction test were carefully selected to represent an industrial forming process for AHSS using the CommDraw TM 220 (Commonwealth Oil Corporation, Harrow, ON, Canada) lubricant provided by the automotive toolmaker, Bowman Precision Tooling.…”

Section: Friction Characterizationmentioning

confidence: 99%

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A Comparative Evaluation of Third-Generation Advanced High-Strength Steels for Automotive Forming and Crash Applications

et al. 2021

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While the third generation of advanced high-strength steels (3rd Gen AHSS) have increasingly gained attention for automotive lightweighting, it remains unclear to what extent the developed methodologies for the conventional dual-phase (DP) steels are applicable to this new class of steels. The present paper provides a comprehensive study on the constitutive, formability, tribology, and fracture behavior of three commercial 3rd Gen AHSS with an ultimate strength level ranging from 980 to 1180 MPa which are contrasted with two DP steels of the same strength levels and the 590R AHSS. The hardening response to large strain levels was determined experimentally using tensile and shear tests and then evaluated in 3D simulations of tensile tests. In general, the strain rate sensitivity of the two 3rd Gen 1180 AHSS was significantly different as one grade exhibited larger transformation-induced behavior. The in-plane formability of the three 1180 MPa steels was similar but with a stark contrast in the local formability whereas the opposite trend was observed for the 3rd Gen 980 and the DP980 steel. The forming limit curves could be accurately predicted using the experimentally measured hardening behavior and the deterministic modified Bressan–Williams through-thickness shear model or the linearized Modified Maximum Force Criterion. The resistance to sliding of the three 3rd Gen AHSS in the Twist Compression Test revealed a comparable coefficient of friction to the 590R except for the electro-galvanized 3rd Gen 1180 V1. An efficient experimental approach to fracture characterization for AHSS was developed that exploits tool contact and bending to obtain fracture strains on the surface of the specimen by suppressing necking. Miniature conical hole expansion, biaxial punch tests, and the VDA 238-100 bend test were performed to construct stress-state dependent fracture loci for use in forming and crash simulations. It is demonstrated that, the 3rd Gen 1180 V2 can potentially replace the DP980 steel in terms of both the global and local formability.

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Section: Friction Characterizationmentioning

confidence: 99%

Section: Friction Characterizationmentioning

confidence: 99%

A Comparative Evaluation of Third-Generation Advanced High-Strength Steels for Automotive Forming and Crash Applications

et al. 2021

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“…The heat transfer between the mold and the blank took into account the pressure-dependent interfacial heat transfer coefficient

given in Table 3 . A constant value of

was selected for the coefficient of friction between the tool and the sheet metal blank as being the average value from tribological investigations on aluminum sheets at elevated temperatures from Noder et al [ 40 ]. The blank sheet was modeled by four-node fully-integrated shell elements (element type 16 in LS-DYNA shell element library) with seven integration points through the thickness, an element edge length of

mm and an initial temperature of

C. The rolling direction (RD) was consistent with the diagonal of the blank sheet.…”

Section: Coupled Thermo-mechanical Finite Element Simulations Of Warm Formingmentioning

confidence: 99%

A Generalized Stress State and Temperature Dependent Damage Indicator Framework for Ductile Failure Prediction in Heat-Assisted Forming Operations

Camberg

Erhart²,

Tröster

2021

Materials

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Heat-assisted forming processes are becoming increasingly important in the manufacturing of sheet metal parts for body-in-white applications. However, the non-isothermal nature of these processes leads to challenges in evaluating the forming limits, since established methods such as Forming Limit Curves (FLCs) only allow the assessment of critical forming strains for steady temperatures. For this reason, a temperature-dependent extension of the well-established GISSMO (Generalized Incremental Stress State Dependent Damage Model) fracture indicator framework is developed by the authors to predict forming failures under non-isothermal conditions. In this paper, a general approach to combine several isothermal FLCs within the temperature-extended GISSMO model into a temperature-dependent forming limit surface is investigated. The general capabilities of the model are tested in a coupled thermo-mechanical FEA using the example of warm forming of an AA5182-O sheet metal cross-die cup. The obtained results are then compared with state of the art of evaluation methods. By taking the strain and temperature path into account, GISSMO predicts greater drawing depths by up to 20% than established methods. In this way the forming and so the lightweight potential of sheet metal parts can by fully exploited. Moreover, the risk and locus of failure can be evaluated directly on the part geometry by a contour plot. An additional advantage of the GISSMO model is the applicability for low triaxialities as well as the possibility to predict the materials behavior beyond necking up to ductile fracture.

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“…In metal forming processes, the contact conditions at the tool/workpiece interfaces vary historically and spatially [5][6][7], leading to complex loading conditions featuring abrupt temperature, load, and speed changes, which could affect the viscosity and mechanochemical behaviour of lubricants. This may lead to premature lubricant breakdown, thus resulting in poor surface quality of the formed components and reduced tool life [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…At elevated temperatures, the transient lubricant behaviours were more pronounced. In the friction tests at the interfacial temperature of up to 230 °С, premature lubricant breakdown occurred, and the transient friction values were affected by lubricant properties and interfacial temperature which resulted in different peak forming forces [11].…”

Section: Introductionmentioning

confidence: 99%

Experimental and modelling studies of the transient tribological behaviour of a two-phase lubricant under complex loading conditions

et al. 2021

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The transient tribological phenomenon and premature lubricant breakdown have been widely observed in metal forming, leading to excessive friction at the contact interfaces. In this research, the transient tribological behaviour of a two-phase lubricant were studied under complex loading conditions, featuring abrupt interfacial temperature, contact load, and sliding speed changes, thus representing the severe interfacial conditions observed in warm/hot metal forming applications. The strong experimental evidence indicates that the evolution of friction was attributed to the physical diminution and chemical decomposition effects. As such, a visco-mechanochemical interactive friction model was developed to accurately predict the transient tribological behaviour of the two-phase lubricant under complex loading conditions. The new friction model exhibited close agreements between the modelling and experimental results.

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Friction characterization and application to warm forming of a high strength 7000-series aluminum sheet

Cited by 18 publications

References 27 publications

A Comparative Evaluation of Third-Generation Advanced High-Strength Steels for Automotive Forming and Crash Applications

A Comparative Evaluation of Third-Generation Advanced High-Strength Steels for Automotive Forming and Crash Applications

A Generalized Stress State and Temperature Dependent Damage Indicator Framework for Ductile Failure Prediction in Heat-Assisted Forming Operations

Experimental and modelling studies of the transient tribological behaviour of a two-phase lubricant under complex loading conditions

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