scholarly journals Behavior of CFRP-Confined Sand-Based Material Columns under Axial Compression

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3994
Author(s):  
Guodong Li ◽  
Honglin Liu ◽  
Wentao Deng ◽  
Hongzhi Wang ◽  
Haitian Yan
Keyword(s):  
Mechanical Response ◽  
Mechanical Performance ◽  
High Strength ◽  
Experimental Tests ◽  
High Water ◽  
Underground Mines ◽  
Uniaxial Compression Test ◽  
The Novel ◽  
Axial Deformation ◽  
Cementing Material

This paper presents an innovative pumpable standing support designed for underground mines located in the arid and semi-arid deserts of the Gobi region with a shortage of water resources. The exterior shell of this pumpable standing support is made of carbon fiber-reinforced polymer (CFRP), while the infill material is a sand-based material (SBM). As the novel backfill material, SBM is the combination of high-water cementing material and desert sand. A series of experimental tests were conducted to obtain the mechanical response mechanism of this novel pumpable standing support under uniaxial compression. Test variables investigated in this research covered the water-to-powder ratio of the cementing material, the mixing amount of sand, and the thickness of the CFRP tube. Test results confirmed that the CFRP-confined SBM columns exhibited typical strain hardening behavior with the acceptable axial deformation. It was also demonstrated that using high-strength cementing material, a thicker CFRP tube, and a high mixing amount of sand effectively increased the bearing capacity of the CFRP-confined SBM column. Except for the exemplary structural behavior, the consumption of high-water cementing materials of the novel pumpable standing support is smaller than that of its counterparts made of pure cementing material, when specimens with the same mechanical performance are compared.

scholarly journals Experimental and Numerical Analysis of 3D Printed Polymer Tetra-Petal Auxetic Structures under Compression

2021 ◽  
Vol 11 (21) ◽  
pp. 10362
Author(s):  
Demetris Photiou ◽  
Stelios Avraam ◽  
Francesco Sillani ◽  
Fabrizio Verga ◽  
Olivier Jay ◽  
...  
Keyword(s):  
Finite Element ◽  
3D Printing ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Poisson Ratio ◽  
Impact Resistance ◽  
Experimental Tests ◽  
Polymer Materials ◽  
Compression Tests ◽  
Auxetic Structures

Auxetic structures possess a negative Poisson ratio (ν < 0) as a result of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and impact resistance, as well as exceptional mechanical response advantages for applications in defense, biomedical, automotive, aerospace, sports, consumer goods, and personal protective equipment sectors. With the advent of additive manufacturing, it has become possible to produce complex shapes with auxetic properties, which could not have been possible with traditional manufacturing. Three-dimensional printing enables easy and precise control of the geometry and material composition of the creation of desirable shapes, providing the opportunity to explore different geometric aspects of auxetic structures with a variety of different materials. This study investigated the geometrical and material combinations that can be jointly tailored to optimize the auxetic effects of 2D and 3D complex structures by integrating design, modelling approaches, 3D printing, and mechanical testing. The simulation-driven design methodology allowed for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with different polymer materials. Compression tests were performed to characterize the auxetic behavior of the different system configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of ν = −0.6 for certain shape and material combinations, thus providing support for preliminary finite element studies on unit cells. Finally, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical performance of the auxetic structures by means of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis.

scholarly journals Physical and Mechanical Performance of Frozen Rocks and Soil in Different Regions

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Junhao Chen ◽  
Lexiao Wang ◽  
Zhaoming Yao
Keyword(s):  
Mechanical Performance ◽  
Failure Strain ◽  
High Strength ◽  
Cohesive Soil ◽  
High Water ◽  
Curing Temperature ◽  
High Water Content ◽  
Jurassic Rocks ◽  
Frozen Wall ◽  
Rock And Soil

The artificial freezing method is extensively used in the reinforcement of engineering strata in various regions for shaft excavation and subway connection channels. In this study, representative rock and soil strata from different regions were subjected to low-temperature physical and mechanical performance tests. The results show that, compared with Cretaceous and Jurassic rock and soil strata, deep topsoil and shallow coastal topsoil have high water content, low thermal conductivities, high frost heave rates, and high freezing temperatures. In addition, the results show that, as the curing temperature decreases, the uniaxial compressive strengths and elastic moduli of deep topsoil and shallow coastal topsoil increase almost linearly. The strength of the sandy soil strata is the highest, followed by the cohesive soil strata, and the strength of the mucky soil and the calcareous clay is the lowest. The strength of the frozen wall and the waterproof requirements must both be taken into account in the freezing design. Deep Cretaceous and Jurassic rocks can have high strength of more than 5 MPa under normal temperature conditions. An increase in the uniaxial compressive strength and elastic modulus with decreasing curing temperature is mainly manifested within the range from the normal temperature to −10°C. The strength can reach more than 10 MPa at −10°C, and only the strength requirements of the frozen wall need to be considered in the freezing design. At low temperatures, deep topsoil and shallow coastal topsoil are dominated by the form of compression failure. The average failure strain at −10°C is typically greater than 5%. When excavating the strata, it is essential to pay attention to the effect of creep. The failure strain of deep Cretaceous and Jurassic rocks is between 1% and 2%, and the breaking and sudden collapse of surrounding rocks should be prevented.

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

scholarly journals Survival Research Laboratories: A Dystopian Industrial Performance Art

Arts ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 17
Author(s):  
Nicolas Ballet
Keyword(s):  
Performance Art ◽  
Mechanical Performance ◽  
Common Interest ◽  
The Novel ◽  
Performance Group ◽  
Leading Role ◽  
Industrial Culture ◽  
Industrial Performance ◽  
Machine Art ◽  
Group Survival

This paper examines the leading role played by the American mechanical performance group Survival Research Laboratories (SRL) within the field of machine art during the late 1970s and early 1980s, and as organized under the headings of (a) destruction/survival; (b) the cyborg as a symbol of human/machine interpenetration; and (c) biomechanical sexuality. As a manifestation of the era’s “industrial” culture, moreover, the work of SRL artists Mark Pauline and Eric Werner was often conceived in collaboration with industrial musicians like Monte Cazazza and Graeme Revell, and all of whom shared a common interest in the same influences. One such influence was the novel Crash! by English author J. G. Ballard, and which in turn revealed the ultimate direction in which all of these artists sensed society to be heading: towards a world in which sex itself has fallen under the mechanical demiurge.

Mechanical performance of honeycomb sandwich structures built by FDM printing technique

2021 ◽  
pp. 089270572199789
Author(s):  
S Gohar ◽  
G Hussain ◽  
A Ali ◽  
H Ahmad
Keyword(s):  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Sandwich Structures ◽  
Weight Ratio ◽  
High Strength ◽  
Core Material ◽  
Interfacial Bond Strength ◽  
Fused Deposition ◽  
Competitive Prices ◽  
Composite Face

Honey Comb Sandwich Structures (HCSS) have numerous applications in aerospace, automobile, and satellite industry because of their properties like high strength to weight ratio, stiffness and impact strength. Fused Deposition Modeling (FDM) is a process which, through its flexibility, simple processing, short manufacturing time, competitive prices and freedom of design, has an ability to enhance the functionality of HCSS. This paper investigates the mechanical behavior (i.e. flexural, edgewise compression and Interfacial bond strength) of FDM-built HCSS. The influence of face/core material was examined by manufacturing four types of specimens namely ABS core with Composite (PLA + 15% carbon fibers) face sheets, ABS core with PLA face sheets, TPU core with composite face sheets and TPU core with PLA face sheets. To measure the effect of face sheets geometry, raster layup was varied at 0°/90° and 45°/−45°. The mechanical characterization revealed that an optimum combination of materials is ABS core with composite face sheets having raster layup of 0°/90°. This study indicates that HCSS with complex lamination schemes and adequate mechanical properties could be manufactured using FDM which may widen the applications of FDM on an industrial scale.

Sign in / Sign up

Export Citation Format

Share Document