Evaluation of superalloy heavy-duty grinding based on multivariate tests

The quality and economy of grinding depend on proper selection of grinding conditions for the materials to be ground. In order to evaluate the effect of heavy-duty grinding, a new performance index, which includes specific material removal rate, size accuracy, and grinding forces, was proposed. Robust design of experiment, including orthogonal arrays, the signal-to-noise ratio (SNR) method, and analysis of variance (ANOVA) for multivariate data, was employed to estimate the effect of uniform experimental design and to optimize grinding parameters. Empirical models of grinding force were investigated for finite element analysis of new fixture design. These empirical models, based on robust design of experiments and multiple regression methodology, have been confirmed through further verification experiments. Correlation coefficients from 0.87 to 0.96 were achieved

Delivering manufacturing technology and workshop appreciation to engineering undergraduates using the flipped classroom approach

Delivery of manufacturing technology and practical workshop-based work, on undergraduate engineering courses that engage the learners, is challenging. The paper presents an experimental method of workshop delivery using the flipped learning approach, a pedagogical model in which the typical lecture and homework elements of a course are reversed. Video lectures are viewed by students prior to class. In-class time can be devoted to exercises, projects, or discussions as in this case. Learners were asked to observe three audiovisual clips in preparation for class. The objective was to determine whether the flipped classroom approach can enhance the learning experience, through better engagement with the students, compared to conventional classroom-based learning. The level of student participation and level of success have been established by means of feedback questionnaires from more than 100 participants and peer observation. The results are encouraging and demonstrate that this approach is favoured by the students

Poster 79 Comprehension of Visual Displays of the Functional Independence Measure (FIM) in Patients with Spinal Cord Injury in Acute Rehabilitation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147222/1/pmrjs187.pd

Confirmatory Factor Analysis of the Patient Health Questionnaire‐9: A Study of the Participants From the Spinal Cord Injury Model Systems

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146986/1/pmr2533.pd

Tribo-corrosion mechanisms of stainless steel in soft drinks

Tribo-corrosion mechanisms of 316L Stainless Steel in slurries containing common household soft drinks have been studied through investigating the micro-abrasion-corrosion performance using a ball and disk apparatus which has been modified to measure the in-situ corrosion current during the abrasion process. The objective of this study was to evaluate the effect of pH and solution viscosity on the micro-abrasion-corrosion performance of the material. 316L Stainless Steel was selected because it is commonly used as a dental replacement material. This is an important area of work as the use of steel retainers as well as other stainless steel dental replacements is still widespread and the effectiveness of these devices will be determined by their tribological and tribo-corrosion performance. Additionally, an attempt has been made to investigate the importance of the pH and viscosity variables on the tribo-corrosive synergism, wastage and mechanism maps

Functional Outcomes of Acute Inpatient Rehabilitation in Patients With Chronic Graft‐Versus‐Host Disease

BackgroundGrowing numbers of allogeneic stem cell transplants and improved posttransplant care have led to an increase of individuals with chronic graft‐versus‐host disease (cGVHD). Although cGVHD leads to functional impairment for many, there is limited literature regarding the benefits of acute inpatient rehabilitation for patients with cGVHD.ObjectiveTo assess Functional Independence Measure (FIM) outcomes of patients with cGVHD during acute inpatient rehabilitation and to compare inpatient rehabilitation outcomes with patients with burn injuries, a rehabilitation patient population with similar comorbidities.DesignRetrospective chart review.SettingAcute rehabilitation center at a large academic medical center.Patients (or Participants)A total of 37 adult patients with cGVHD and 30 with burn injuries admitted to inpatient rehabilitation from 2010 to 2015.Methods or InterventionsLinear regression analysis to evaluate group (cGVHD versus burn) differences in functional gains. Effect size and minimal detectable change at the 90% confidence level (MDC90) were used to evaluate change in FIM outcomes.Main Outcome MeasurementsTotal FIM gain, motor FIM gain, and FIM efficiency.ResultsPatients with cGVHD had statistically significant lower functional gains than patients with burn injuries, with an average of 11.66 fewer total FIM points (P ≤ .001), 10.54 fewer motor FIM points (P = .01), and 2.45 units less of FIM efficiency (P = .01). At the time of discharge, 7 (18%) patients with cGVHD exceeded the MDC90 values for total FIM gain versus 9 (30%) patients with burn injuries (P = .26). Eight (21%) patients with cGVHD exceeded the MDC90 for motor FIM gain versus 13 (43%) patients with burn injuries (P = .048). Effect sizes for patients with cGVHD and with burn injury were moderate to large, respectively, with patients with burn injuries having nearly twice the magnitude of gains as patients with cGVHD.ConclusionsDespite achieving more modest functional gains than patients with burn injuries, patients with cGVHD improved in function after acute inpatient rehabilitation. If replicated in larger studies, patients with functional impairment from cGVHD can be considered for inpatient rehabilitation. Future work should also determine minimal clinically important differences in function gain from inpatient rehabilitation for patients with cGVHD.Level of EvidenceIIPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147101/1/pmr2567.pd

Sustainability Analysis of AISI 1018 Turning Operations under Surface Integrity Criteria

[EN] While the world is moving towards achieving sustainable development goals for responsible production and consumption, there is a need for metrics deployment for lower practical levels. From a manufacturing perspective, definitions of sustainability indicators are required for industrial processes and operations. These metrics encourage the evaluation of manufactured parts and whether they meet the quality requirements in both a qualitative and quantitative way. The present contribution proposes a framework for defining a structured set of metrics customizable for operations in different manufacturing technologies. In order to validate the proposal, an experimental data analysis of turning operations was completed and the surface integrity was defined as the control feature. The selected material was AISI 1018 and the main process parameters were controlled in order to identify their influence¿not only in the final mechanical quality of the part, but also in the sustainability indicators. To achieve this goal, a set of experiments was performed wherein some of the fundamental machining parameter values were fixed, while other key parameters were modified. The results obtained helped to determine the criteria for predicting the quality of the turning operation when the effects are not readily evident in visual or dimensional inspections, as well as in evaluating the environmental impact that guarantees optimal part manufacturingThis research was funded by Escuela Politecnica Nacional (Ecuador) Research Project: PIS 16-15, Universitat Politecnica de Valencia UPV (Spain) and Carolina Foundation (Spanish Government Scholarships) call 2017Vila, C.; Ayabaca-Sarria, C.; Díaz-Campoverde, C.; Calle, O. (2019). Sustainability Analysis of AISI 1018 Turning Operations under Surface Integrity Criteria. Sustainability. 11(17):1-17. https://doi.org/10.3390/su11174786S1171117Davim, J. P. (Ed.). (2017). Sustainable Machining. Materials Forming, Machining and Tribology. doi:10.1007/978-3-319-51961-6Jawahir, I. S., Brinksmeier, E., M’Saoubi, R., Aspinwall, D. K., Outeiro, J. C., Meyer, D., … Jayal, A. D. (2011). Surface integrity in material removal processes: Recent advances. CIRP Annals, 60(2), 603-626. doi:10.1016/j.cirp.2011.05.002Singh, K., & Sultan, I. (2018). A Computer-Aided Sustainable Modelling and Optimization Analysis of CNC Milling and Turning Processes. Journal of Manufacturing and Materials Processing, 2(4), 65. doi:10.3390/jmmp2040065Kishawy, H., Hegab, H., & Saad, E. (2018). Design for Sustainable Manufacturing: Approach, Implementation, and Assessment. Sustainability, 10(10), 3604. doi:10.3390/su10103604Bhanot, N., Rao, P. V., & Deshmukh, S. G. (2016). An Assessment of Sustainability for Turning Process in an Automobile Firm. Procedia CIRP, 48, 538-543. doi:10.1016/j.procir.2016.03.024Cioca, L.-I., Breaz, R.-E., & Racz, S.-G. (2019). Reducing the Risks during the Purchase of Five-Axis CNC Machining Centers Using AHP Method and Fuzzy Systems. Sustainability, 11(2), 315. doi:10.3390/su11020315Kluczek, A. (2017). Quick Green Scan: A Methodology for Improving Green Performance in Terms of Manufacturing Processes. Sustainability, 9(1), 88. doi:10.3390/su9010088(2018). Identification and Alignment of the Social Aspects of Sustainable Manufacturing with the Theory of Motivation. Sustainability, 10(3), 852. doi:10.3390/su10030852Leskovar, P., & Peklenik, J. (1982). Influences Affecting Surface Integrity in the Cutting Process. CIRP Annals, 31(1), 447-450. doi:10.1016/s0007-8506(07)63345-9Lalwani, D. I., Mehta, N. K., & Jain, P. K. (2008). Experimental investigations of cutting parameters influence on cutting forces and surface roughness in finish hard turning of MDN250 steel. Journal of Materials Processing Technology, 206(1-3), 167-179. doi:10.1016/j.jmatprotec.2007.12.018Sasahara, H. (2005). The effect on fatigue life of residual stress and surface hardness resulting from different cutting conditions of 0.45%C steel. International Journal of Machine Tools and Manufacture, 45(2), 131-136. doi:10.1016/j.ijmachtools.2004.08.002Jayal, A. D., Badurdeen, F., Dillon, O. W., & Jawahir, I. S. (2010). Sustainable manufacturing: Modeling and optimization challenges at the product, process and system levels. CIRP Journal of Manufacturing Science and Technology, 2(3), 144-152. doi:10.1016/j.cirpj.2010.03.006Pan, Z., Feng, Y., & Liang, S. Y. (2017). Material microstructure affected machining: a review. Manufacturing Review, 4, 5. doi:10.1051/mfreview/2017004Wang, F., Zhao, J., Li, A., & Zhang, H. (2014). Effects of cutting conditions on microhardness and microstructure in high-speed milling of H13 tool steel. The International Journal of Advanced Manufacturing Technology, 73(1-4), 137-146. doi:10.1007/s00170-014-5812-9Nagendhra, S., Rami reddy, A. S., & Preetham Kumar, G. V. (2018). Workability Study on Austempered AISI 1018. IOP Conference Series: Materials Science and Engineering, 376, 012049. doi:10.1088/1757-899x/376/1/012049Mohsan, A. U. H., Liu, Z., Ren, X., & Liu, W. (2018). Influences of cutting fluid conditions and cutting parameters on surface integrity of Inconel 718 under high-pressure jet-assisted machining (HPJAM). Lubrication Science, 30(6), 269-284. doi:10.1002/ls.1418Hwang, Y.-K., Lee, C.-M., & Park, S.-H. (2009). Evaluation of machinability according to the changes in machine tools and cooling lubrication environments and optimization of cutting conditions using Taguchi method. International Journal of Precision Engineering and Manufacturing, 10(3), 65-73. doi:10.1007/s12541-009-0049-5Yang, S., Talekar, T., Sulthan, M. A., & Zhao, Y. F. (2017). A Generic Sustainability Assessment Model towards Consolidated Parts Fabricated by Additive Manufacturing Process. Procedia Manufacturing, 10, 831-844. doi:10.1016/j.promfg.2017.07.086Lu, L., Sun, J., Han, X., & Xiong, Q. (2016). Study on the Surface Integrity of a Thin-Walled Aluminum Alloy Structure after a Bilateral Slid Rolling Process. Metals, 6(5), 99. doi:10.3390/met6050099Gupta, M., Pruncu, C., Mia, M., Singh, G., Singh, S., Prakash, C., … Gill, H. (2018). Machinability Investigations of Inconel-800 Super Alloy under Sustainable Cooling Conditions. Materials, 11(11), 2088. doi:10.3390/ma11112088Yue, C., Gao, H., Liu, X., & Liang, S. (2018). Part Functionality Alterations Induced by Changes of Surface Integrity in Metal Milling Process: A Review. Applied Sciences, 8(12), 2550. doi:10.3390/app8122550Pawade, R. S., Joshi, S. S., & Brahmankar, P. K. (2008). Effect of machining parameters and cutting edge geometry on surface integrity of high-speed turned Inconel 718. International Journal of Machine Tools and Manufacture, 48(1), 15-28. doi:10.1016/j.ijmachtools.2007.08.004Bordin, A., Bruschi, S., & Ghiotti, A. (2014). The Effect of Cutting Speed and Feed Rate on the Surface Integrity in Dry Turning of CoCrMo Alloy. Procedia CIRP, 13, 219-224. doi:10.1016/j.procir.2014.04.03

Critical Buckling Loads of the Perfect Hollomon's Power-law Columns

In this work, we present analytic formulas for calculating the critical buckling states of some plastic axial columns of constant cross-sections. The associated critical buckling loads are calculated by Euler-type analytic formulas and the associated deformed shapes are presented in terms of generalized trigonometric functions. The plasticity of the material is defined by the Hollomon's power-law equation. This is an extension of the Euler critical buckling loads of perfect elastic columns to perfect plastic columns. In particular, critical loads for perfect straight plastic columns with circular and rectangular cross-sections are calculated for a list of commonly used metals. Connections and comparisons to the classical result of the Euler-Engesser reduced-modulus loads are also presented.Comment: 15 page