NONLINEAR APPROACH OF TEACHING VARIOUS MECHANICAL FORMING OPERATIONS IN STUDYING ENGINEERING SCIENCES

2015 ◽  
Vol 1 (1) ◽  
pp. 75-81
Author(s):  
Rytis Bortkevičius ◽  
Author(s):  
Carmen Popa ◽  
Violeta Anghelina ◽  
Octavian Munteanu

Abstract The descriptive geometry constitues the foundation of the engineering sciences, so necessary to the specialists of this field. The aim of this paper is to establish the intersection curve between two cylinders and their unfoldings, by using the programmes:AutoCAD and Mathematica. We used the classical method and we first establish the intersection curve and then the cylinders unfoldings. To do this, we used the AutoCAD program. The same unfoldings can be obtained by introducing directly the curve equations (which are inferred) in Mathematica program.


2011 ◽  
Vol 15 (3) ◽  
pp. 45
Author(s):  
Hyunchul Lee ◽  
Minkyo Seo

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 58 ◽  
Author(s):  
Francesco Clementi

This paper presents a detailed study of the damages and collapses suffered by various masonry churches in the aftermath of the seismic sequence of Central Italy in 2016. The damages will first be analyzed and then compared with the numerical data obtained through 3D simulations with eigenfrequency and then nonlinear static analyses (i.e., pushover). The main purposes of this study are: (i) to create an adequately consistent sensitivity study on several definite case studies to obtain an insight into the role played by geometry—which is always unique when referred to churches—and by irregularities; (ii) validate or address the applicability limits of the more widespread nonlinear approach, widely recommended by the Italian Technical Regulations. Pushover analyses are conducted assuming that the masonry behaves as a nonlinear material with different tensile and compressive strengths. The consistent number of case studies investigated will show how conventional static approaches can identify, albeit in a qualitative way, the most critical macro-elements that usually trigger both global and local collapses, underlining once again how the phenomena are affected by the geometry of stones and bricks, the texture of the wall face, and irregularities in the plan and elevation and in addition to hypotheses made on the continuity between orthogonal walls.


Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 474
Author(s):  
Abdulhakim A. Al-Babtain ◽  
Ibrahim Elbatal ◽  
Hazem Al-Mofleh ◽  
Ahmed M. Gemeay ◽  
Ahmed Z. Afify ◽  
...  

In this paper, we introduce a new flexible generator of continuous distributions called the transmuted Burr X-G (TBX-G) family to extend and increase the flexibility of the Burr X generator. The general statistical properties of the TBX-G family are calculated. One special sub-model, TBX-exponential distribution, is studied in detail. We discuss eight estimation approaches to estimating the TBX-exponential parameters, and numerical simulations are conducted to compare the suggested approaches based on partial and overall ranks. Based on our study, the Anderson–Darling estimators are recommended to estimate the TBX-exponential parameters. Using two skewed real data sets from the engineering sciences, we illustrate the importance and flexibility of the TBX-exponential model compared with other existing competing distributions.


2021 ◽  
Vol 13 (8) ◽  
pp. 4236
Author(s):  
Tim Lu

The selection of advanced manufacturing technologies (AMTs) is an essential yet complex decision that requires careful consideration of various performance criteria. In real-world applications, there are cases that observations are difficult to measure precisely, observations are represented as linguistic terms, or the data need to be estimated. Since the growth of engineering sciences has been the key reason for the increased utilization of AMTs, this paper develops a fuzzy network data envelopment analysis (DEA) to the selection of AMT alternatives considering multiple decision-makers (DMs) and weight restrictions when the input and output data are represented as fuzzy numbers. By viewing the multiple DMs as a network one, the data provided by each DM can then be taken into account in evaluating the overall performances of AMT alternatives. In the solution process, we obtain the overall and DMs efficiency scores of each AMT alternative at the same time, and a relationship in which the former is a weighted average of the latter is also derived. Since the final evaluation results of AMTs are fuzzy numbers, a ranking procedure is employed to determine the most preferred one. An example is used to illustrate the applicability of the proposed methodology.


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