MMaterialsgateNEWS 2018/04/11

A UC3M study analyzes the keys to fragmentation of metallic materials

Credit: UC3M

Researchers from Universidad Carlos III de Madrid (UC3M), Texas A&M (USA) and the Israeli Institute of Technology have developed new theories for the fragmentation of metallic porous materials that can be applied to structural design in the aerospace, civil security and transportation sectors.

The scientists have analyzed the mechanisms which reside behind the phenomenon of dynamic fragmentationof ductile metallic materials, that is, those that exhibit large permanent deformations when they are subjected to severe mechanical loading (steel, aluminum, tantalum…). Previously it was thought that dynamic fragmentation was basically triggeredby the inherent defects of the material (pores). What this research suggests is thatthe key mechanism which controls dynamic fragmentation may not be the porosity of the metallic material (defects), but the inertia effects.

One of the authors of the study, Komi Espoir N'Souglo, pointed out that “we have developed a simple analytical model to shed light into the mechanisms which control dynamic fragmentation in porous metals used in the aerospace industry and the civilian-security sector”. This scientist works in this research line at UC3M within the European research project OUTCOME.

“This work provides a new approach for analyzing and designing structures for which it is important to predict and control the size of the fragments that form when a metallic material fractures under impact loading,” added OUTCOME project coordinator, José Antonio Rodríguez, from the Department of Continuum Mechanics and Structural Analysis, and coauthor of the paper recently published in the journal Proceedings of the Royal Society A.

Possible applications

The identification of the mechanisms which control dynamic fragmentation of a material used to build protective structures will lead to the optimization of their manufacturing processes, reducing costs (economic, environmental…) and improving the quality of the final products. For example, in the case of protective structures of industrial facilities such as nuclear power plants, it is very important that these will be capable of withstanding extrememechanical loads such as explosions and impacts without fragmenting, thus maintaining their load-carrying capacity. “This knowledge can also be applied in the design of structures that can easily be fragmented, as in the case of space debris that sometimes falls to the earth’s surface. In this case, the aim is that during the atmospheric re-entry the space debris will be fragmented so that the structures that eventually reach the earth’s surface are not of a large size,” the researchers explained.

OUTCOME is a project of the European Union Research, Technological Development and Innovation Programme (reference number GA 675602). This research consortium, coordinated by UC3M and formed by SMEs and Universities from Spain, France and Israel, aims to train early stage researchers in the analysis and design of structures subjected to extreme loading conditions, used in the aerospace and civilian-security sectors. These types of structures, such as components and parts of satellites, must be designed to withstand extreme temperatures, which can vary hundreds of degrees in short spans of time and extreme mechanical loads, such as hypervelocity impacts.

Source: Universidad Carlos III de Madrid – 09.04.2018.

Bibliographic references:

K. E. N’souglo, A. Srivastava, S. Osovski and J. A. Rodríguez-Martínez. Random distributions of initial porosity trigger regular necking patterns at high strain rates. Proceedings of the Royal Society A, Proc R Soc A 0000000 (2018)

Investigated and edited by:

Dr.-Ing. Christoph Konetschny, Inhaber und Gründer von Materialsgate
Büro für Material- und Technologieberatung
The investigation and editing of this document was performed with best care and attention.
For the accuracy, validity, availability and applicability of the given information, we take no liability.
Please discuss the suitability concerning your specific application with the experts of the named company or organization.

You want additional material or technology investigations concerning this subject?

Materialsgate is leading in material consulting and material investigation.
Feel free to use our established consulting services

MMore on this topic

Researchers find an ultrathin layer of aluminum oxide, though solid, can flow like a liquid instead of cracking.

Researchers have found that a solid oxide protective coating for metals can, when applied in sufficiently thin layers, deform as if it were a liquid, filling any cracks and gaps as they form. The thin coating layer should be especially useful to prevent leakage of tiny molecules that can penetrate through most materials, such as hydrogen gas that could be used to power fuel-cell cars, or the radioactive tritium (a heavy form of hydrogen) that forms inside the cores of nuclear power plants. Most metals, with the notable exception of gold, tend to oxidize when exposed to air and water. This reaction, which produces rust on iron, tarnish on silver, and verdigris on copper or brass, can weaken... more read more

New research from North Carolina State University and the U.S. Army’s Aviation Applied Technology Directorate shows that stainless steel composite metal foam (CMF) can block blast pressure and fragmentation at 5,000 feet per second from high explosive incendiary (HEI) rounds that detonate only 18 inches away.

“In short, we found that steel-CMF offers much more protection than all other existing armor materials while lowering the weight remarkably,” says Afsaneh Rabiei, senior author of a paper on the work and a professor of mechanical and aerospace engineering at NC State. “We can provide as much protection as existing steel armor at a fraction of the weight – or provide much more protection at the same weight. “Many military vehicles use armor made of rolled homogeneous steel, which weighs three times as much as our steel-CMF,” Rabiei says. “Based on tests like these, we believe we can replace that rolled steel with steel-CMF without sacrificing safety, better blocking not only... more read more

Synthesizing organic scaffolds that contain metal ions enables 3-D printing of metallic structures that are orders of magnitude smaller than previously possible

For the first time, it is possible to create complex nanoscale metal structures using 3-D printing, thanks to a new technique developed at Caltech. The process, once scaled up, could be used in a wide variety of applications, from building tiny medical implants to creating 3-D logic circuits on computer chips to engineering ultralightweight aircraft components. It also opens the door to the creation of a new class of materials with unusual properties that are based on their internal structure. The technique is described in a study that will be published in Nature Communications on February 9. In 3-D printing—also known as additive manufacturing—an object is built layer by layer, allowing... more read more


Partner of the Week

Search in MaterialsgateNEWS

Books and products