An iterative numerical method for determination of temperature-dependent friction coefficients in thermomechanical model analysis of cold bolt forging

Abstract

A set of temperature-dependent friction coefficients was developed to increase the accuracy of finite element (FE) simulations of cold bolt forging. The initially attained friction coefficients at different temperatures were calibrated with the iterations between the experimental and thermomechanical model extrusion test loads. The constant friction coefficient and the determined set of friction coefficients as function of temperature were then implemented to the simulations of the cold bolt-forging processes. Further calibrations and model validations were made based on the temperature measurements of the workpiece in the actual bolt-forging processes. To show the advantages of developed temperature-dependent friction coefficients, the loads of four different bolt-forging processes were compared with the thermomechanical model loads calculated using the constant friction and temperature-dependent friction coefficients. The modeling results indicated that the use of temperature-dependent friction coefficients in the FE simulations resulted in nearer temperature distributions and the loads of the workpiece during forging as compared with the use of a constant friction coefficient.

Resistance spot welding process simulation for variational analysis on compliant assemblies

“…The study of Ince and Güden [36] about cold bolt forging shows a reduction of the friction coefficient for an increment in temperature up to 200 • C, then it increase again up to 400 • C. In order to detach from the coupled materials, the values of the friction coefficient were normalised by dividing them for the static friction coefficient at ambient temperature 0 . The resulting friction parameter is defined as f T = (T)/ 0 and its behaviour is sketched in Fig.…”

Mechanical Behavior and Reliability of Anchoring Resin under Thermomechanical Coupling

“…The stress state of the anchor in deep mines differs greatly from that in shallow mines. Thus, the resin anchoring system, consisting of the anchor, the resin anchored layer and the surrounding rock, in deep mines must have vastly different mechanical features from that in shallow mines [13][14]. The supporting effect of the rock anchoring system hinges on the mechanical reliability of the resin anchored layer [15].…”

Evaluation of rheological behavior and interfacial friction under the adhesive condition by upsetting method

“…Up to now, some efforts have been done on rheological behavior and interfacial friction against specific friction phenomenon, and a large number of studies have been carried out in sheet [3][4][5][6][7] and bulk [8][9][10][11][12][13][14][15] metal forming to evaluate the rheological behavior and interfacial friction. Some parameter estimation approaches, such as direct method and inverse method [16,17], were developed to analyze rheological behavior and interfacial friction; meanwhile, many test methods, such as forward extrusion [18], forward-backward extrusion [19], ring upsetting [20][21][22], cylinder upsetting [23,24], multi-layered upsetting test [3], double-cup extrusion [25][26][27], upsetting-sliding [28], backward extrusion [29], and T-shape compression test [30], were presented to analyze rheological behavior and interfacial friction.…”