Mechanical Engineering in Europe

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 16494

Special Issue Editor

Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, 00184 Rome, Italy
Interests: fatigue and fracture behavior of materials; mechanical characterization; structural integrity of conventional and innovative materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue is titled “Mechanical Engineering Europe”. In Europe, many research groups, from both industry and academia, are working on different aspects of mechanical engineering and structural integrity. The topics are strongly connected with industrial applications in different fields. In particular, advanced and innovative processes have been recently developed for the fabrication of mechanical parts that now require an overall structural integrity characterization. As an example, welding and joining, in general, have tremendously improved in the last few years.  Subtractive and additive process have been quickly developed, providing new opportunities but also new challenges.  The capacity for making a multi-scale design of a part and its topological optimization has been leading to unprecedented products and parts. In addition, knowledge in mechanical engineering, for example, on fatigue design, is becoming fundamental for the accurate design of large aluminum and steel structures.

Taking into account these recent developments, scientists from Europe are cordially invited to contribute original research papers or reviews to this Special Issue of Applied Science, which reports on recent trends in mechanical design, processes and structural integrity.

Prof. Dr. Filippo Berto
Guest Editor

Manuscript Submission Information

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Keywords

  • Mechanical design
  • Joining
  • Welding
  • Bolting
  • Topology optimization
  • Structural integrity
  • Fatigue and fracture
  • Material design
  • Case studies in mechanical engineering

Published Papers (6 papers)

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Research

17 pages, 3831 KiB  
Article
Statistical Characterization of Stress Concentrations along Butt Joint Weld Seams Using Deep Neural Networks
by Moritz Braun, Josef Neuhäusler, Martin Denk, Finn Renken, Leon Kellner, Jan Schubnell, Matthias Jung, Klemens Rother and Sören Ehlers
Appl. Sci. 2022, 12(12), 6089; https://doi.org/10.3390/app12126089 - 15 Jun 2022
Cited by 8 | Viewed by 2173
Abstract
In order to ensure high weld qualities and structural integrity of engineering structures, it is crucial to detect areas of high stress concentrations along weld seams. Traditional inspection methods rely on visual inspection and manual weld geometry measurements. Recent advances in the field [...] Read more.
In order to ensure high weld qualities and structural integrity of engineering structures, it is crucial to detect areas of high stress concentrations along weld seams. Traditional inspection methods rely on visual inspection and manual weld geometry measurements. Recent advances in the field of automated measurement techniques allow virtually unrestricted numbers of inspections by laser measurements of weld profiles; however, in order to compare weld qualities of different welding processes and manufacturers, a deeper understanding of statistical distributions of stress concentrations along weld seams is required. Hence, this study presents an approach to statistically characterize different types of butt joint weld seams. For this purpose, an artificial neural network is created from 945 finite element simulations to determine stress concentration factors at butt joints. Besides higher quality of predictions compared to empirical estimation functions, the new approach can directly be applied to all types welded structures, including arc- and laser-welded butt joints, and coupled with all types of 3D-measurement devices. Furthermore, sheet thickness ranging from 1 mm to 100 mm can be assessed. Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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27 pages, 8710 KiB  
Article
Assessment of the Durability of Threaded Joints
by Žilvinas Bazaras, Mindaugas Leonavičius, Vaidas Lukoševičius and Laurencas Raslavičius
Appl. Sci. 2021, 11(24), 12162; https://doi.org/10.3390/app112412162 - 20 Dec 2021
Cited by 3 | Viewed by 2698
Abstract
The article deals with the determination of the resistance to cyclic loading of the threaded joints of pressure vessels and defective elements according to the failure mechanics criteria. Theoretical and experimental studies do not provide a sufficient basis for the existing calculation methods [...] Read more.
The article deals with the determination of the resistance to cyclic loading of the threaded joints of pressure vessels and defective elements according to the failure mechanics criteria. Theoretical and experimental studies do not provide a sufficient basis for the existing calculation methods for the cyclic strength of the threaded joints of pressure vessels. The short crack kinetics in the threaded joints, a shakedown in one of the joint elements of pressure vessels, i.e., in the bolt or stud, has not been studied sufficiently. The calculation methods designed and improved within the study were based on theoretical and experimental investigations and were simplified for convenient application to engineering practice. The findings could be used to investigate the shakedown of studs of a different cross-section with an initiating and propagating crack. Value: the developed model for the assessment of durability of the threaded joints covers the patterns of resistance to cyclic failure (limit states: crack initiation, propagation, final failure) and shakedown (limit states: progressive shape change and plastic failure). Analysis-based solutions of plastic failure conditions and progressive shape change were accurate (the result was reached using a two-sided approach; the solutions were obtained in view of the parameters of the cyclic failure process in the stud (bolt) and based on experimental investigations of the threaded joints). Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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35 pages, 5193 KiB  
Article
Determination of Local Stresses and Strains within the Notch Strain Approach: The Efficient and Accurate Calculation of Notch Root Strains Using Finite Element Analysis
by Lukas Masendorf, Ralf Burghardt, Michael Wächter and Alfons Esderts
Appl. Sci. 2021, 11(24), 11656; https://doi.org/10.3390/app112411656 - 08 Dec 2021
Viewed by 2867
Abstract
For the service life estimation of metallic components under cyclic loading according to strain-based approaches, a simulation of the elastic-plastic stress–strain path at the point of interest is necessary. An efficient method for determining this stress–strain path is the use of the load–notch-strain [...] Read more.
For the service life estimation of metallic components under cyclic loading according to strain-based approaches, a simulation of the elastic-plastic stress–strain path at the point of interest is necessary. An efficient method for determining this stress–strain path is the use of the load–notch-strain curve, as this is also implemented within the FKM guideline nonlinear. The load–notch-strain curve describes the relationship between the load on the component and the local elastic-plastic strain. On the one hand, this can be estimated from loads or theoretical elastic stresses by using notch root approximations. On the other hand, this can be determined in a finite element analysis based on the elastic-plastic material behaviour. This contribution describes how this latter option is carried out in general and how it can be optimised in such a way that the FEA requires significantly less calculation time. To show the benefit of this optimisation, a comparative calculation on an exemplary geometry is carried out. Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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16 pages, 7668 KiB  
Article
Gearbox Mechanical Efficiency Determination by Strain Gauges Direct Application
by František Lopot, Martin Dub, Jan Flek, Daniel Hadraba, Martin Havlíček, Lukáš Kučera, Ondřej Štoček, Tomáš Veselý and Jiří Janáček
Appl. Sci. 2021, 11(23), 11150; https://doi.org/10.3390/app112311150 - 24 Nov 2021
Cited by 4 | Viewed by 2733
Abstract
This article describes a unique method of measuring the efficiency of gearboxes using foil strain gauges, which allows maintaining the current configuration of the gearbox within the overall assembly of the machine and its functional condition. The presented method is applicable to gearboxes [...] Read more.
This article describes a unique method of measuring the efficiency of gearboxes using foil strain gauges, which allows maintaining the current configuration of the gearbox within the overall assembly of the machine and its functional condition. The presented method is applicable to gearboxes located in the original equipment assembly without the need to use a test rig. Using foil strain gauges, the torque at the input and output of the gearbox is detected. Therefore, the accuracy of torque measurement is key. The crucial step is the calibration of the instrumentation to the given application conditions, which, in this case, is ensured by a virtual calibration using a very accurate FEM analysis. The accuracy of the position of strain gauges and virtual calibration of measurements generate inaccuracies affecting the resulting uncertainty of the determined efficiency. The present article shows, on the example of several measurements, that when using 24-bit converters, after processing the obtained data, mechanical stress with a sensitivity better than hundredths of an MPa can be reliably detected even without signal amplification from strain gauges. It follows that the efficiency is determined with an accuracy of better than low units of tenths. Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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23 pages, 1689 KiB  
Article
Determination of Local Stresses and Strains within the Notch Strain Approach: Efficient Implementation of Notch Root Approximations
by Ralf Burghardt, Lukas Masendorf, Michael Wächter and Alfons Esderts
Appl. Sci. 2021, 11(21), 10339; https://doi.org/10.3390/app112110339 - 03 Nov 2021
Cited by 4 | Viewed by 1917
Abstract
An estimation of the elastic-plastic stress state using elasticity-theoretical input data is an essential part of the service life estimation with the local strain approach in general and a German guideline based on it, in particular. This guideline uses two different notch root [...] Read more.
An estimation of the elastic-plastic stress state using elasticity-theoretical input data is an essential part of the service life estimation with the local strain approach in general and a German guideline based on it, in particular. This guideline uses two different notch root approximations (an extended version of Neuber’s rule and an approach according to Seeger and Beste) for this estimation. Both require the implementation of Newton’s method to be iteratively solved. However, many options are left open to the user concerning implementation in program code. This paper discusses ways in which notch root approximation methods can be implemented efficiently for use in software systems and elaborates an application recommendation. The following aspects and their influence on the computational accuracy and performance of Newton’s method are considered in detail: influence of the formulation of the root finding problem, determination of the derivative required for Newton’s method and influence of the termination criterion. The investigation shows that the advice given in the abovementioned guideline indeed leads to a conservative implementation. By carefully considering the investigated aspects, however, the computational performance can be increased by approximately a factor of 2–3 without influencing the accuracy of the service life estimation. Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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13 pages, 8845 KiB  
Article
A Comparative Numerical Analysis on the Effect of Welding Consumables on the Ballistic Resistance of SMAW Joints of Armor Steel
by Ambuj Saxena, Shashi Prakash Dwivedi, Shubham Sharma, Vishal Shankar Srivastava, Gursharan Singh, Jujhar Singh, Somnath Chattopadhyaya and Catalin I. Pruncu
Appl. Sci. 2021, 11(8), 3629; https://doi.org/10.3390/app11083629 - 17 Apr 2021
Cited by 6 | Viewed by 2070
Abstract
In the present investigation, a comparative study of ballistic impact behavior of Armox 500T (base metal) and its weldments prepared by low hydrogen ferrite (weldment-1) and austenitic stainless steel (weldment-2) consumables against 7.62 AP bullet has been performed with the help of finite [...] Read more.
In the present investigation, a comparative study of ballistic impact behavior of Armox 500T (base metal) and its weldments prepared by low hydrogen ferrite (weldment-1) and austenitic stainless steel (weldment-2) consumables against 7.62 AP bullet has been performed with the help of finite element analysis code Abaqus 2017. Further, the result is validated with the experimental results. The experiment has been performed on the base metal, weldment-1, and weldment-2 against 7.62 AP bullet. Further, a two-dimensional explicit model has been developed for given purpose to simulate the bullet penetration at such high strain rate (103 s−1). Both bullet and plate are considered as deformable. Experimental results revealed that the depth of penetration in the base metal, weldment-1, and weldment-2 is 10.93, 13.65, and 15.20 mm respectively. Further computational results revealed that the depth of penetration of base metal, weldment-1, and weldment-2 is 10.11, 12.87, and 14.60 mm, respectively. Furthermore, weldment-1 shows more resistance against 7.62 AP bullet than weldment-2 in experimentation as well as FEA results. The percentage difference between experimental and FEA results are less than 10% which shows the prediction capability of FEA models. A feasibility analysis has been presented for using the welding consumables to weld the Armox 500T plate. Finally, in terms of ballistic resistance, the low hydrogen ferrite consumables are more appropriate than austenitic stainless-steel electrodes. Full article
(This article belongs to the Special Issue Mechanical Engineering in Europe)
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