scholarly journals Bioinspired cementitious-polymer composite for increased energy absorption

2021 ◽  
Vol 349 ◽  
pp. 01012
Author(s):  
T. Trevor Painter ◽  
Emily Schwab ◽  
Nicole MacCrate ◽  
Alexander S. Brand ◽  
Eric Jacques
Keyword(s):  
Fracture Energy ◽  
Energy Absorption ◽  
High Performance ◽  
Deformation Behaviour ◽  
Image Correlation ◽  
Three Point Bending ◽  
Global Strain ◽  
Brick And Mortar ◽  
Energy Absorbing ◽  
Total Fracture

Preliminary results are presented on the energy absorbing characteristics of a cementitious-polymer architecture bioinspired by the organic-inorganic composite structure of nacre. The proposed bioinspired architecture consists of an open cell, platelet-shaped 3D-printed thermoplastic lattice filled with high performance cementitious paste. The hypothesis is that, similar to nacre, the platelet arrangement and differences in mechanical properties of the thermoplastic lattice and cementitious platelets would result in increased energy absorption. Initial laboratory scale investigations were performed using notched beam samples subjected to static three-point bending. Stereo-digital image correlation was used to track global strain displacement field and Hillerborg’s method was used to estimate the total fracture energy. The results indicate that this “brick-and-mortar” hierarchy can increase the energy absorbing capacity of the composite by upwards of 2490% compared with the benchmark cementitious specimen. The load-deformation behaviour and total fracture energy of the bioinspired composite were found to be influenced by the platelet arrangement and size and the lattice thickness.

scholarly journals Locally Produced UHPC: The Influence of Type and Content of Steel Fibres

2021 ◽  
Vol 64 (1) ◽  
pp. 31-52
Author(s):  
Ingrid Lande ◽  
Rein Terje Thorstensen
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Deformation Behaviour ◽  
Image Correlation ◽  
Material Strength ◽  
Content Type ◽  
Steel Fibres ◽  
Flexural Tensile Strength ◽  
Southern Norway

Abstract Ultra-high performance concrete might be a competitive alternative to normal concrete for some purposes. But despite research efforts during decades, utilisation is still not widespread. Reasons include limited competence and material availability. This paper presents one step of a research initiative aimed at facilitating the use of UHPC in Norway. The step presented here comprises the accumulated results from investigations on the influence steel fibres (content, type, and hybrid combination) have on material strength and deformation behaviour of locally produced UHPC, made with constituents found in southern Norway. 231 specimens were tested, spanning nine UHPC mixes. Digital Image Correlation (DIC) was successfully used to study crack propagation. Compressive strength of 166 MPa and E-modulus of 46 GPa were obtained, not being influenced by fibre content. The flexural tensile strength was found to be strongly dependent on variations in steel fibre properties and mix design. The highest flexural tensile strength was obtained for prisms with micro straight steel fibres alone, or in 50% combination with macro hooked-end fibres. The experimental results are considered in a theory-informed discussion. Suggestions are made on the use of steel fibres in locally produced UHPC, potentially lowering the cost by 30%.

Analysing the Deformation Behaviour of Compacted Graphite Cast Irons Using Digital Image Correlation Techniques

2010 ◽  
Vol 457 ◽  
pp. 470-475 ◽  
Author(s):  
Torsten Sjögren ◽  
Per Eric Persson ◽  
Peter Vomacka
Keyword(s):  
Digital Image Correlation ◽  
Tensile Test ◽  
Digital Image ◽  
Deformation Behaviour ◽  
Image Correlation ◽  
Cast Irons ◽  
Graphite Phase ◽  
Compacted Graphite ◽  
Global Strain ◽  
Correlation Techniques

During the last years the use of digital image correlation techniques (DIC) has become wide spread within different areas of research. One area in which these techniques are used is in the analysis of deformation of engineering materials. By the analysis of a set of successive images taken during a tensile test DIC makes it possible to determine how the deformation is localized. The observed local strains are often several times higher than the global strain measured by standard strain gauges. In this study, a set of compacted graphite cast irons (CGI) with different ratios of pearlite to ferrite have been examined by the use of DIC. In contrast to the normal use of DIC, where a pattern is sprayed on the tensile test sample as a reference for the determination of deformation taking place between successive images, the materials natural microstructural pattern has been used in this study. The use of the natural microstructural pattern makes it possible to study how the macroscopic deformation is accommodated within the different phases in the CGI studied. It is shown that the graphite phase accommodates a large portion of the strain and that the soft ferrite is strained more than the stronger, less ductile pearlite. The local strain of the observed area might be up to ten times higher than the global strain measured. The use of DIC improves the understanding of the deformation behaviour of compacted graphite cast irons and will be a useful tool when validating future finite element analyses of the micro-mechanical properties of cast irons.

scholarly journals Design and Numerical Simulation of Pyramidal Prefolded Patterned Thin-Walled Tubes

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Junxian Zhou ◽  
Chuang Dong ◽  
Bingzhi Chen ◽  
Xu Niu
Keyword(s):  
Energy Absorption ◽  
High Performance ◽  
Geometric Analysis ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Comparative Results ◽  
Energy Absorbing ◽  
Deformation Modes

An improved pyramidal prefolded pattern was designed and applied to thin-walled tubes. This delicately designed pattern modularizes the tube to control the folding process and act as an inducer to trigger deformation modes with outstanding crushing performance. Dynamic crushing tests were conducted numerically; the simulation results reveal that the patterned square tube developed a deformation mode with shorter wavelength, better load consistencies, and higher energy-absorption efficiency (up to 29%) than that of the traditional counterpart. Moreover, geometric analysis was performed and structural improvements were conducted by applying the optimal geometric parameters onto an octagonal profile. The designed patterned octagonal tube collapsed into a highly efficient deformation mode known as diamond mode. Furthermore, the comparative results show that patterned octagonal tubes demonstrated an energy absorption up to 90.1% higher than that of a conventional square column while improving the geometric compliance. These findings enrich research on patterned tubes and provide new explorations for the development of high-performance energy-absorbing structures.

Influence of Bias Voltage on Corrosion Resistance of TiN Coated on Biomedical TiZrNb Alloy

2013 ◽  
Vol 845 ◽  
pp. 436-440 ◽  
Author(s):  
A. Shah ◽  
S. Izman ◽  
Mohammed Rafiq Abdul Kadir ◽  
H. Mas-Ayu ◽  
Mahmood Anwar ◽  
...  
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
High Performance ◽  
Indentation Test ◽  
Complex Deformation ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Important Concern ◽  
Polyester Matrix ◽  
Chopped Strand Mat

Recently, Composite Sandwich Panel (CSP) technology considerably influenced the design and fabrication of high performance structures. Although using CSP increases the reliability of structure, the important concern is to understand the complex deformation and damage evolution process. This study is focused on the flexural and indentation behavior of CSP made of chopped strand mat glass fiber and polyester matrix as face sheets and polyurethane foam as foam core subject to flexural and indentation loading condition. A setup of three-point bending and indentation test is prepared using different strain rates of 1mm/min, 10mm/min, 100mm/min and 500mm/min to determine the effects of strain rate on flexural and indentation behavior of CSP material. The load-extension, stress-extension response and energy absorption of the panel show the relation between the flexural and indentation behavior of panels to strain rate as by increasing the strain rate, the flexural properties and the energy absorption of panel are increased.

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

Bioinspired strengthening and toughening carbon nanotube@polyaniline/graphene film using electroactive biomass as glue for high rate, volumetric capacitance and low-temperature tolerance flexible supercapacitor

2021 ◽  
Author(s):  
Dan Wu ◽  
Chuying Yu ◽  
Wenbin Zhong
Keyword(s):  
Carbon Nanotube ◽  
High Performance ◽  
Graphene Film ◽  
Temperature Tolerance ◽  
High Rate ◽  
Flexible Supercapacitor ◽  
Low Temperature Tolerance ◽  
Electrical Devices ◽  
Brick And Mortar ◽  
Volumetric Capacitance

Natural nacre built up with brick-and-mortar architecture, exhibiting extraordinary strength and toughness, provides an inspiration to construct high-performance multifunctional film for flexible energy storage and portable electrical devices. In the...

scholarly journals Energy Absorption Characteristics of Foam Filled Tri Circular Tube under Bending Loads

2021 ◽  
Vol 15 ◽  
pp. 159-164
Author(s):  
Fauzan Djamaluddin
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Circular Tube ◽  
Comparative Investigation ◽  
Tubular Structures ◽  
Vehicle Engineering ◽  
Bending Resistance ◽  
Bending Loads ◽  
Foam Filled ◽  
Energy Absorbing

In this study, the researcher carried out a comparative investigation of the crashworthy features of different tubular structures with a quasi-static three bending point, like the foam-filled two and tri circular tube structures. Energy absorption capacities and failure modes of different structures are also studied. Furthermore, the general characteristics are investigated and compared for instance the energy absorption, specific energy absorption and energy-absorbing effectiveness for determining the potential structural components that can be used in the field of vehicle engineering. Experimental results indicated that under the bending conditions, the tri foam-filled structures were higher crashworthiness behaviour than the two foam-filled circular structures. Therefore, this study recommended the use of crashworthy structures, such as foam-filled tri circular tubes due to the increased bending resistance and energy-absorbing effectiveness.

scholarly journals Novel cellular materials for energy absorption applications

2020 ◽  
Author(s):  
Mohammed Mudassir ◽  
Mahmoud Mansour
Keyword(s):  
Additive Manufacturing ◽  
Energy Absorption ◽  
Metal Foams ◽  
Cellular Materials ◽  
Cellular Structures ◽  
Senior Project ◽  
Key Factor ◽  
Good Energy ◽  
To Come ◽  
Energy Absorbing

Cellular materials such as metal foams are porous, lightweight structures that exhibit good energy absorption properties. They have been used for many years in various applications including energy absorption. Traditional cellular structures do not have consistent pore sizes and their behaviors and properties such as failure mechanisms and energy absorption are not always same even within the same batch. This is a major obstacle for their applications in critical areas where consistency is required. With the popularity of additive manufacturing, new interest has garnered around fabricating metal foams using this technology. It is necessary to study the possibility of designing cellular structures with additive manufacturing and their energy absorbing behavior before any sort of commercialization for critical applications is contemplated. The primary hypothesis of this senior project is to prove that energy absorbing cellular materials can be designed. Designing in this context is much like how a car can be designed to carry a certain number of passengers. To prove this hypothesis, the paper shows that the geometry is a key factor that affects energy absorption and that is possible to design the geometry in order to obtain certain behaviors and properties as desired. Much like designing a car, it requires technical expertise, ingenuity, experience and learning curve for designing cellular structures. It is simple to come with a design, but not so much when the design in constrained by stringent requirements for energy absorption and failure behaviors. The scope was limited to the study of metal foams such as the ones made from aluminum and titanium. The primary interest has been academic rather than finding ways to commercialize it. The study has been carried out using simulation and experimental verification has been suggested for future work. Nevertheless, the numerical or simulation results show that energy absorbing cellular structures can be designed that exhibit good energy absorption comparable to traditional metal foams but perhaps with better consistency and failure behaviors. The specific energy absorption was found to be 18 kJ/kg for aluminum metal foams and 23 kJ/kg for titanium metal foams. The average crushing force has been observed to be around 70 kN for aluminum and around 190 kN for titanium. These values are within the acceptable range for most traditional metal foams under similar conditions as simulated in this paper.

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