Linear and Nonlinear Model of Cutting Forces in Peripheral Milling: A Comparison Between 2D and 3D Models

Author(s):  
Hamed Moradi ◽  
Mohammad R. Movahhedy ◽  
Gholamreza Vossoughi

Peripheral milling is extensively used in manufacturing processes, especially in aerospace industry where end mills are used for milling of wing parts and engine components. Knowledge of the cutting forces is the first necessary stage in analysis of the milling process. In this paper, cutting forces are presented for both two and three dimensional models. Instead of the common linear dependency of cutting forces to the cut chip thickness, two nonlinear models are presented. In the first model, cutting forces are considered as a function of chip thickness with a complete third order polynomial. In the second one, the quadratic and constant terms of the third order polynomial are set to zero. Results show about 2–3% and 2–7% maximum error between the linear, first and second nonlinear models, for 2D and 3D models, respectively. According to the simulation results, both the 2D and 3D models with second type of nonlinearity can be effectively used in practice. The advantage of such modelling is its simplicity in nonlinear analysis of the problem based on perturbation techniques.

2021 ◽  
Vol 8 (1) ◽  
pp. 11
Author(s):  
Sorel E. De Leon ◽  
Lana Cleuren ◽  
Zay Yar Oo ◽  
Paul R. Stoddart ◽  
Sally L. McArthur

Three-dimensional (3D) cell cultures have recently emerged as tools for biologically modelling the human body. As 3D models make their way into laboratories there is a need to develop characterisation techniques that are sensitive enough to monitor the cells in real time and without the need for chemical labels. Impedance spectroscopy has been shown to address both of these challenges, but there has been little research into the full impedance spectrum and how the different components of the system affect the impedance signal. Here we investigate the impedance of human fibroblast cells in 2D and 3D collagen gel cultures across a broad range of frequencies (10 Hz to 5 MHz) using a commercial well with in-plane electrodes. At low frequencies in both 2D and 3D models it was observed that protein adsorption influences the magnitude of the impedance for the cell-free samples. This effect was eliminated once cells were introduced to the systems. Cell proliferation could be monitored in 2D at intermediate frequencies (30 kHz). However, the in-plane electrodes were unable to detect any changes in the impedance at any frequency when the cells were cultured in the 3D collagen gel. The results suggest that in designing impedance measurement devices, both the nature and distribution of the cells within the 3D culture as well as the architecture of the electrodes are key variables.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Gui-ying Qiao ◽  
Yu-meng Liu ◽  
Jun-si Wang ◽  
Fu-ren Xiao

Abstract The weld joint is the weakest zone of a longitudinal-seam submerged arc welded (LSAW) pipe, which has great effects on its in-service properties and safety. The weld geometry and shape of the weld joint are important factors that affect the mechanical properties of the pipe. In this work, two-dimensional (2D) and three-dimensional (3D) finite element models (FEMs) of a large-diameter, heavy-wall API X80 LSAW pipe were established, and the stress distribution of the pipe was calculated to simulate the in-service gas transmission pipeline. Results showed that the stress distribution calculated by both 2D and 3D models are similar. Consequently, the effects of weld geometry, softening of heat affected zone (HAZ), and strength matching of the weld joint on bearing pressure capability of the pipe were analyzed, and the results showed that the bearing pressure capability of the pipe can be improved by controlling these parameters. These results are beneficial in providing references for welding parameter design and improved properties of the X80 LSAW pipe.


2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0015
Author(s):  
Jarrett D. Cain ◽  
Jordan T. Stolle ◽  
Sorin Siegler

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Hallux valgus (HV) is a tri-plane deformity of the foot corresponding to a medial deviation of the first metatarsal and a lateral deviation of the hallux. Understanding key angles between bones, as well as how these deformity changes in each plane, is critical to generating pre-operative insights into the most effective surgical correction of the deformity. While two- dimenional (2D) imaging can provide some information; utilizing three-dimensional (3D) imaging can include more precise and accurate measures of hallux valgus. The purpose of this study is to evaluate the metatarsal osteotomies for correction of hallux valgus deformity in axial, coronal and sagittal plane with 2D and 3D measurements with the hypothesis that 3D measurements will provide greater accuracy of pre and post surgical changes Methods: Ten cadaveric specimens were selected and weight-bearing CT scans were taken pre operatively with an applied an axial load of 80 pounds. Midshaft osteotomies were then performed on the cadaveric specimens followed by weight-bearing CT scans taken post-operatively.3D models of the pre-operative and post-operative specimens were created and differences in pre and post operative changes were analyzed using conventional 2D and 3D models of the first metatarsal (M1), second metatarsal (M2), fifth metatarsal (M5), and proximal phalanx of the hallux (PP1) using a paired student t-test. Quantitative examination of foot and ankle offset (FAO) alignment along with congruity of first metatarsal phalangeal and first tarsometatarsal joints Results: 3D measurements of the Inter-Metatarsal (IM) Angle, was 12.3 degrees pre-opeative and 10.4 degrees post-operative with no significant differences in all three planes while the M1M5 Angle, measured between the principle axes of the first metatarsal and fifth metatarsal was 25.3 degrees pre-operative and 22.0 degrees post-operative were statistically significant with the greatest change in the axial plane. 2D measurements of the hallux valgus angle, measured the longitudineal axes of the first metatarsal and proximal phalange of the hallux was 22.6 degrees pre opereative and 21.7 degrees post opereative with no statistical difference while the metatarsal parabola, measured in two dimensions projected onto the axial plane was 157.1 degrees before and 141.5 degrees after surgery was statistical significant. Conclusion: When comparing 2D and 3D pre and post surgical hallux valgus values, the only significant differences were identified in the absolute M1M5 values in the axial plane and a significant change was also observed in the metatarsal parabola angle. While the metatarsal parabola angle are sensitive measures, these results suggest that the M1 M5 angle allows for precise, efficient measurements in axial, coronal and sagittal planes that is previously unknown through two-dimensional radiographic measurements for quantifying the effect of metatarsal osteotomies on hallux valgus


2013 ◽  
Vol 405-408 ◽  
pp. 2015-2019 ◽  
Author(s):  
Joanna M. Dulinska ◽  
Anna Galuszka

The paper indicates the role of 3D modeling of concrete gravity dams in evaluation of dynamic response of dams to mining tremors which occur in mining activity regions. 2D and 3D models of a concrete gravity dam were prepared in order to compare two-and three-dimensional analysis of the dynamic response of dam to mining shock. Firstly, values of natural frequencies obtained for 2D and 3D models occurred to be very similar, but only the 3D model allowed to predict the dam behaviour under longitudinal kinematic excitation. Secondly, the comparison of the maximal principal stresses obtained for 2D and 3D models indicates that the simplified 2D analysis underestimates the values of dynamic response on about 20 %. Three-dimensional dynamic analysis allows to assess internal stresses resulting from mining shock more precisely, since the amplitudes of ground vibrations during mining tremors are comparable in three directions.


1978 ◽  
Vol 1 (16) ◽  
pp. 63
Author(s):  
A.M. Davies

This paper describes how a two-dimensional numerical model of the North Sea was used to determine optimum positions for the deployment of off-shore tide gauges during the JONSDAP '76 oceanographic exercise. A three-dimensional model of the North West European Shelf is also described. Using this model the three-dimensional distribution of the M2 tidal current over the shelf has been computed. This model has also been used to compute the wind induced circulation of the North Sea for the INOUT period of JONSDAP '76.


Author(s):  
Chengfeng Li ◽  
Xinmin Lai ◽  
Hongtao Li ◽  
Linfa Peng ◽  
Jun Ni

This paper develops a three-axis micro milling machine for manufacturing meso-scale components and products. This machine utilizes high-speed miniature spindle to obtain appropriate cutting velocities, and three precision linear stages with 50 nm feed resolution to supply the relative motion. The PMAC2 controller is used to control three axes simultaneously, and a piezoelectric dynamometer is mounted on the X-Y stages to measure three-dimensional cutting forces for the real-time measurement and feedback. More than 200 cutting experiments of end milling operations are performed on the developed machine. When the machined feature ranges at meso scale, the characteristics and phenomena in milling process will heavily differ from those of conventional scale milling due to the size effects. The critical differences at meso scale arise from the breakdown of the assumptions of negligible edge radius effects. The roundness of cutting edge and the runout of spindle have a crucial impact on the chip formation process and the characteristics of cutting forces. The roundness of cutting edge also induces the existence of the minimum chip thickness and the intermittency of the chip formation at a low feed per tooth.


2018 ◽  
Vol 7 (4.35) ◽  
pp. 662
Author(s):  
Erly Bahsan ◽  
Rifani Fakhriyyanti

Slope stability analyses are performed mostly as a two-dimensional (2D) section under the assumption of plane strain conditions, without much consideration to the impact of three-dimensional (3D) shapes. For natural slopes that have the complexities of slope surfaces, 3D modeling may also be considered since it can represent the more realistic geometry of the slope. However, previous studies show that the factor of safety (FS) as a result of 3D analyses mostly overestimated the FS from 2D analyses. This may lead to a long discussion on whether the 3D analysis is still applicable for the natural slopes, and could it represent the same results as the 2D analysis. This study was conducted using the finite element method for calculating the 2D and 3D FS of Pasir Muncang natural slope in order to observe differences of FS resulted from both analyses. A comparison of the FS from the 2D and 3D analyses, and also verification of sensitivity on several factors that impact the 2D and 3D models have been performed. The results of this study has indicated that some factors such as soil parameters, contour interval, and mesh coarseness greatly affect the results of the 2D and 3D calculations. Having carefully selected the aforementioned factors as the inputs for calculations, the difference between the FS values of 3D and 2D analyses becomes smaller. The final result of FS for this case study from the 3D analysis was still higher than the one from the 2D analysis, with the ratio of FS from 3D to FS from 2D was 1.44. It can be inferred that the use of 3D analyses needs more accurate data selections compared to the 2D analyses.  


2013 ◽  
Vol 325-326 ◽  
pp. 1324-1328 ◽  
Author(s):  
Joanna Dulinska

The paper indicates the role of 3D modeling of concrete gravity dams in evaluation of dynamic response of dams to mining tremors which occur in mining activity regions. 2D and 3D models of a concrete gravity dam were prepared in order to compare two-and three-dimensional analysis of the dynamic response of dam to mining shock. Firstly, values of natural frequencies obtained for 2D and 3D models occurred to be very similar, but only the 3D model allowed to predict the dam behaviour under longitudinal kinematic excitation. Secondly, the comparison of the maximal principal stresses obtained for 2D and 3D models indicates that the simplified 2D analysis underestimates the values of dynamic response on about 20 %. Three-dimensional dynamic analysis allows to assess internal stresses resulting from mining shock more precisely, since the amplitudes of ground vibrations during mining tremors are comparable in three directions.


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