Investigation on Clinching with Additional Local Material Bond by Thermal Joining

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

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Local material symmetry group for first- and second-order strain gradient fluids

Mathematics and Mechanics of Solids ◽

10.1177/10812865211021640 ◽

2021 ◽

pp. 108128652110216

Author(s):

Victor A. Eremeyev

Keyword(s):

Symmetry Group ◽

Strain Gradient ◽

Constitutive Equations ◽

Strain Energy ◽

Mass Density ◽

Material Model ◽

Second Order ◽

Material Symmetry ◽

Local Material ◽

Current Mass

Using an unified approach based on the local material symmetry group introduced for general first- and second-order strain gradient elastic media, we analyze the constitutive equations of strain gradient fluids. For the strain gradient medium there exists a strain energy density dependent on first- and higher-order gradients of placement vector, whereas for fluids a strain energy depends on a current mass density and its gradients. Both models found applications to modeling of materials with complex inner structure such as beam-lattice metamaterials and fluids at small scales. The local material symmetry group is formed through such transformations of a reference placement which cannot be experimentally detected within the considered material model. We show that considering maximal symmetry group, i.e. material with strain energy that is independent of the choice of a reference placement, one comes to the constitutive equations of gradient fluids introduced independently on general strain gradient continua.

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Identification of Mode Shapes of a Composite Cylinder Using Convolutional Neural Networks

Materials ◽

10.3390/ma14112801 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2801

Author(s):

Bartosz Miller ◽

Leonard Ziemiański

Keyword(s):

Neural Networks ◽

Convolutional Neural Networks ◽

Composite Structures ◽

Three Dimensional ◽

Mode Shapes ◽

Identification Algorithm ◽

Material Degradation ◽

Local Material ◽

Noisy Input ◽

Shape Vector

The aim of the following paper is to discuss a newly developed approach for the identification of vibration mode shapes of multilayer composite structures. To overcome the limitations of the approaches based on image analysis (two-dimensional structures, high spatial resolution of mode shapes description), convolutional neural networks (CNNs) are applied to create a three-dimensional mode shapes identification algorithm with a significantly reduced number of mode shape vector coordinates. The CNN-based procedure is accurate, effective, and robust to noisy input data. The appearance of local damage is not an obstacle. The change of the material and the occurrence of local material degradation do not affect the accuracy of the method. Moreover, the application of the proposed identification method allows identifying the material degradation occurrence.

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Residual stress/strain evolution due to low‐cycle fatigue by removing local material volume and optical interferometric data

Fatigue & Fracture of Engineering Materials & Structures ◽

10.1111/ffe.13083 ◽

2019 ◽

Vol 42 (9) ◽

pp. 2061-2078

Author(s):

Yury Matvienko ◽

Vladimir Pisarev ◽

Svyatoslav Eleonsky ◽

Andrey Chernov

Keyword(s):

Residual Stress ◽

Low Cycle Fatigue ◽

Cycle Fatigue ◽

Stress Strain ◽

Strain Evolution ◽

Local Material ◽

Material Volume

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Sicily Before the Greeks. The Interaction with Aegean and the Levant in the Pre-colonial Era

Open Archaeology ◽

10.1515/opar-2020-0107 ◽

2020 ◽

Vol 6 (1) ◽

pp. 172-205

Author(s):

Davide Tanasi

Keyword(s):

Material Culture ◽

Complex Dynamics ◽

Eastern Mediterranean ◽

Colonial Era ◽

Local Material ◽

Gradual Process ◽

Multiple Variables ◽

New Perspective ◽

First Time ◽

The Relationship

AbstractThe relationship between Sicily and the eastern Mediterranean – namely Aegean, Cyprus and the Levant – represents one of the most intriguing facets of the prehistory of the island. The frequent and periodical contact with foreign cultures were a trigger for a gradual process of socio-political evolution of the indigenous community. Such relationship, already in inception during the Neolithic and the Copper Age, grew into a cultural phenomenon ruled by complex dynamics and multiple variables that ranged from the Mid-3rd to the end of the 2nd millennium BCE. In over 1,500 years, a very large quantity of Aegean and Levantine type materials have been identified in Sicily alongside with example of unusual local material culture traditionally interpreted as resulting from external influence. To summarize all the evidence during such long period and critically address it in order to attempt historical reconstructions is a Herculean labor.Twenty years after Sebastiano Tusa embraced this challenge for the first time, this paper takes stock on two decades of new discoveries and research reassessing a vast amount of literature, mostly published in Italian and in regional journals, while also address the outcomes of new archaeometric studies. The in-depth survey offers a new perspective of general trends in this East-West relationship which conditioned the subsequent events of the Greek and Phoenician colonization of Sicily.

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Considering multiple process observables to determine material model parameters for FE-cutting simulations

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06845-6 ◽

2021 ◽

Author(s):

Marvin Hardt ◽

Thomas Bergs

Keyword(s):

Chip Thickness ◽

Material Model ◽

Experimental Investigations ◽

Model Parameters ◽

Inverse Approach ◽

Local Material ◽

Novel Approach ◽

Validation Parameters ◽

Multiple Process ◽

Cutting Simulations

AbstractAnalyzing the chip formation process by means of the finite element method (FEM) is an established procedure to understand the cutting process. For a realistic simulation, different input models are required, among which the material model is crucial. To determine the underlying material model parameters, inverse methods have found an increasing acceptance within the last decade. The calculated model parameters exhibit good validity within the domain of investigation, but suffer from their non-uniqueness. To overcome the drawback of the non-uniqueness, the literature suggests either to enlarge the domain of experimental investigations or to use more process observables as validation parameters. This paper presents a novel approach merging both suggestions: a fully automatized procedure in conjunction with the use of multiple process observables is utilized to investigate the non-uniqueness of material model parameters for the domain of cutting simulations. The underlying approach is two-fold: Firstly, the accuracy of the evaluated process observables from FE simulations is enhanced by establishing an automatized routine. Secondly, the number of process observables that are considered in the inverse approach is increased. For this purpose, the cutting force, cutting normal force, chip temperature, chip thickness, and chip radius are taken into account. It was shown that multiple parameter sets of the material model can result in almost identical simulation results in terms of the simulated process observables and the local material loads.

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Bending tests on GLT beams having well-known local material properties

Materials and Structures ◽

10.1617/s11527-014-0424-2 ◽

2014 ◽

Vol 48 (11) ◽

pp. 3571-3584 ◽

Cited By ~ 9

Author(s):

Gerhard Fink ◽

Andrea Frangi ◽

Jochen Kohler

Keyword(s):

Material Properties ◽

Bending Tests ◽

Local Material ◽

Local Material Properties

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Analysis of Factors Affecting Technological Innovativeness in Engineering Enterprises in Tanzania

Tanzania Journal of Engineering and Technology ◽

10.52339/tjet.v34i1.454 ◽

2010 ◽

Vol 34 (1) ◽

pp. 1-14

Author(s):

Emmanuel A. Mjema

Keyword(s):

Innovation Management ◽

Positive Culture ◽

Key Factors ◽

Factors Affecting ◽

Level Of Education ◽

Fundamental Innovation ◽

Local Material ◽

The Right

This paper discusses the technological innovativeness in engineering enterprises in Tanzania and analyses the factors affecting the innovativeness. It starts by analyzing various concepts regarding innovation, then analyzed from documentary review factors affecting innovativeness and then analyzed the innovativeness in Tanzanian enterprises.From the documentary review it was learnt that the following key factors influence technological innovativeness: Existence of innovation management; Existence of market to absorb the products of innovation; Existence of partnership between the universities and the firms; Existence of positive culture and politics towards innovation; The governmentplaying its role to influence innovation; Existence of the right knowledge; and Ability of the enterprises to access to financing institutions that support innovation.The research shows that there is hardly any fundamental innovation in Tanzania, what is presented as innovation is the copying of technologies and manufacture them using local material. Theresearcher established the following factors affecting the innovativeness of engineering enterprises in Tanzania: Level of education among the entrepreneurs in engineering enterprises; financing for the enterprises in Tanzania; partnership with R&D institutions; innovativeness culture; and market for Tanzanian products.

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Phytoplankton in the embayments of King George Island (Antarctic Peninsula): a review with emphasis on diatoms

Polar Record ◽

10.1017/s0032247418000232 ◽

2018 ◽

Vol 54 (2) ◽

pp. 158-175 ◽

Cited By ~ 1

Author(s):

Priscila Kienteca Lange ◽

Ryszard Ligowski ◽

Denise Rivera Tenenbaum

Keyword(s):

Antarctic Peninsula ◽

Early Summer ◽

Western Antarctic Peninsula ◽

King George Island ◽

Accurate Identification ◽

Phytoplankton Assemblages ◽

Marine Food Web ◽

Planktonic Diatoms ◽

Local Material ◽

Marine Food

ABSTRACTConsidering that phytoplankton assemblages are good bioindicators of environmental conditions, the sensitivity of the Western Antarctic Peninsula (WAP) to climate change, and the importance of some areas of its islands as Antarctic Specially Managed Areas, this work assembles published datasets on phytoplankton biodiversity and ecology in confined coastal areas (embayments) of King George Island, WAP. Over 33 years (1980–2013), 415 species from 122 genera have been identified to species level, being mostly diatoms (371 species), with 10 new species described with local material (6 diatoms, 4 cyanobacteria). The importance of diatoms was indicated by the frequent occurrence of Corethron pennatum, Pseudogomphonema kamtshaticum, and abundant benthic genera in the plankton (e.g. Navicula, Cocconeis). The increased contribution of dinoflagellates after 2010 suggests marked changes in the water column. Early-summer blooms differ between the bays' eastern and western shores, with terrestrial melting and wind-driven upwelling inducing the dominance of benthic species at eastern shores, whereas planktonic diatoms (Thalassiosira, Pseudo-nizschia, and Chaetoceros) are most abundant along western shores and central areas. The importance of an accurate identification of organisms that are becoming key ecological components of the region is discussed, as recent changes in the microflora may affect the entire marine food web.

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