scholarly journals Structural Behavior of Ferrocement Concrete Plates Subjected to Flexural and Dynamic Loadings

2021 ◽  
pp. 71-84
Author(s):  
Yousry B. I. Shaheen ◽  
Fatma M. Eid ◽  
Omnia Mesalam
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Ultimate Load ◽  
Test Results ◽  
High Impact Energy ◽  
Absorption Properties ◽  
Steel Mesh ◽  
Dynamic Loadings ◽  
Steel Bars ◽  
The Impact

Ferrocement is one of the structural materials, widely used due to its advantages from its particular behavior such as mechanical properties, and impact strength. This paper deals with the impact studies and energy absorption properties of ferrocement slabs. For these studies, 11 different ferrocement slabs of size 50 mm X 500 mm X 25 mm were cast with alteration in the combinations of mesh layers and test results are analyzed to find the different crack patterns .The test specimens were loaded by 3.10 kg under its height 1.20 m in the center of plates. The ferrocement plates were divided into 4 groups reinforced with steel mesh, steel mesh with steel bars, percentage of rubber and fiber. The impact energy at initial cracking stage and at failure was determined for all the slabs. Results of reinforced ferrocement plates emphasized that increasing the number of the steel mesh layers in the ferrocement forms increases the first cracking load, ultimate load and energy absorption. Using steel bars with steel meshes led to higher energy absorption than that obtained when using mild steel bars only. Using rubber and fiber achieved high impact energy.

Effect of SiO2 Nanoparticles on the Mechanical and Low Velocity Impact Properties of Epoxy/Glass Composites

2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Impact Energy ◽  
Epoxy Matrix ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Nanoparticle Suspension ◽  
Impact Properties ◽  
Velocity Impact ◽  
The Impact

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).

scholarly journals Aluminium Foams in the Design of Transport Means

1970 ◽  
Vol 24 (4) ◽  
pp. 295-304 ◽  
Author(s):  
Krešimir Grilec ◽  
Gojko Marić ◽  
Katica Miloš
Keyword(s):  
Energy Absorption ◽  
Mechanical Energy ◽  
Aluminium Foam ◽  
Test Machine ◽  
Test Results ◽  
Compression Tests ◽  
Compression Behaviour ◽  
Low Weight ◽  
Good Energy ◽  
The Impact

The requirements for weight reduction and improvement of performances in the design of transport means are often in contradiction to the requirements for increased safety. One of the possible ways of meeting these requirements is the application of metal foams. Thanks to cellular structure of aluminium foam along with low weight, the capability of noise and vibration damping, they feature also excellent capabilities of absorbing impact energy. Their application in the production of impact-sensitive elements of mobile or stationary transport means has significantly contributed to the reduction of the impact or collision consequences.The focus of this paper is on improving the energy absorption characteristics of aluminium foams considering the significance of their application for the technology of traffic and transport.The paper analyzes the influence of the chemical composition and density on the compression behaviour of aluminium foam. The aluminium foam samples were produced from Alulight precursor. The capability of samples to absorb mechanical energy has been estimated according to the results of compression tests. The tests were performed on a universal test machine. The test results showed that aluminium foams feature good energy absorption and the absorption capability decreases with the foam density. The Alulight AlMgSi 0.6 TiH2 - 0.4 foam can absorb more energy than Alulight AlSi 10 TiH2 – 0.8 foam.

Interplay of fabric structure and shear thickening fluid impregnation in moderating the impact response of high-performance woven fabrics

2020 ◽  
Vol 54 (28) ◽  
pp. 4387-4395
Author(s):  
Sanchi Arora ◽  
Abhijit Majumdar ◽  
Bhupendra Singh Butola
Keyword(s):  
Beneficial Effect ◽  
Energy Absorption ◽  
Impact Energy ◽  
High Performance ◽  
Research Work ◽  
Impact Resistance ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Fabric Structure ◽  
The Impact

The beneficial effect of STF impregnation in enhancing the impact resistance of high-performance fabrics has been extensively reported in the literature. However, this research work reports that fabric structure has a decisive role in moderating the effectiveness of STF impregnation in terms of impact energy absorption. Plain woven fabrics having sett varying from 25 × 25 inch−1 to 55 × 55 inch−1 were impregnated with STF at two different padding pressures to obtain different add-ons. The impact energy absorption by STF impregnated loosely woven fabrics was found to be higher than that of their neat counterparts for both levels of add-on, while opposite trend was observed in case of tightly woven fabrics. Further, comparison of tightly woven plain, 2/2 twill, 3/1 twill and 2 × 2 matt fabrics revealed beneficial effect of STF impregnation, except for the plain woven fabric, establishing that there exists a fabric structure-STF impregnation interplay that tunes the impact resistance of woven fabrics.

Dynamic Energy Absorption Performances of Rain Forest Vehicle (RFV) under Frontal Impact

2014 ◽  
Vol 67 (3) ◽  
Author(s):  
M. S. Othman ◽  
Z. Ahmad
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Impact Loading ◽  
Rain Forest ◽  
Experimental Testing ◽  
Rigid Wall ◽  
Crash Analysis ◽  
Frontal Impact ◽  
Frontal Section ◽  
The Impact

This paper treats the crash analysis and energy absorption response of Rain Forest Vehicle (RFV) subjected to frontal impact scenario namely impacting rigid wall and column. Dynamic computer simulation techniques validated by experimental testing are used to carry out a crash analysis of such vehicle. The study aims at quantifying the energy absorption capability of frontal section of RFV under impact loading, for variations in the load transfer paths and geometry of the crashworthy components. It is evident that the proposed design of the RFV frontal section are desirable as primary impact energy mitigation due to its ability to withstand and absorb impact loads effectively. Furthermore, it is found that the impact energy transmitted to the survival room may feasibly be minimized in these two impact events. The primary outcome of this study is design recommendation for enhancing the level of safety of the off-road vehicle where impact loading is expected.   

Experimental and Numerical Investigation on the Load Carrying Behavior of Large Ship Windows

2014 ◽  
Author(s):  
Wolfgang Fricke ◽  
Bjarne Gerlach ◽  
Matthias Guiard
Keyword(s):  
Ultimate Load ◽  
Impact Loads ◽  
Test Results ◽  
Lateral Loads ◽  
Load Range ◽  
Filled Rubber ◽  
Load Carrying ◽  
Drop Tests ◽  
Load Tests ◽  
The Impact

Aboard ships windows are exposed to static as well as dynamic loads, e.g. impact loads. Failure can lead to serious consequences. Therefore two research projects were initiated in order to analyze the load carrying behavior of windows. In addition to quasi-static ultimate load tests and drop tests with water filled rubber bags special attention is paid to the Finite Element (FE) modeling. In particular the response — stresses and deformations — to quasi-static lateral loads can be calculated with good agreement to test results. Hence FE calculations can be useful to determine and compare failure mechanisms of different window designs. An ultimate load range can be estimated by taking into account the breaking strength range of glass. A comparison between FE calculations and results of the impact tests showed that these are sensitive to conditions which could hardly be measured during the test, e.g. the shape of the approaching water-filled rubber bag. Varying of parameters eventually yielded that window response to impact loads can also be calculated sufficiently, at least, to evaluate different window designs. Further investigations on this topic are in progress.

Wear behaviors of WC and TiC on co matrix composites under three-body impact abrasive wear condition

2019 ◽  
Vol 71 (7) ◽  
pp. 893-900 ◽  
Author(s):  
Lei Dong ◽  
Xiaoyu Zhang ◽  
Kun Liu ◽  
Xiaojun Liu ◽  
Ruiming Shi ◽  
...  
Keyword(s):  
Wear Rate ◽  
Abrasive Wear ◽  
Impact Energy ◽  
Wear Behavior ◽  
High Impact ◽  
Impact Wear ◽  
High Impact Energy ◽  
Content Type ◽  
Three Body ◽  
The Impact

Purpose The purpose of this paper is to investigate the tribological properties of the WC/TiC-Co substrate under different loading conditions under three impact abrasive wear conditions. Design/methodology/approach The three body collisional wear behavior of Co alloy with WC and TiC at three impact energy was studied from 1 to 3 J. Meanwhile, the microstructure, hardness, phase transformation and wear behavior of these specimens were investigated by scanning electron microscopy, Rockwell hardness (HRV), EDS and impact wear tester. The resulting wear rate was quantified by electronic balance measurements under different pressures. Findings The specific wear rate increases with the increase of the nonlinearity of the impact energy and the increase in the content of WC or TiC. The effect of TiC on wear rate is greater than that of WC, but the hardness is smaller. The wear characteristics of the samples are mainly characterized by three kinds of behavior, such as cutting wear, abrasive wear and strain fatigue wear. The WC-Co with fewer TiC samples suffered heavier abrasive wear than the more TiC samples under both low and high impact energy and underwent fewer strain fatigue wears under high impact energy. Originality/value The experimental results show that the wear resistance of the Co alloy is improved effectively and the excellent impact wear performance is achieved. The results can be used in cutting tools such as coal mine cutting machines or other fields.

Development of Splice Connections for Precast Concrete Structures

2014 ◽  
Vol 980 ◽  
pp. 132-136 ◽  
Author(s):  
Ahmad Baharuddin Abd Rahman ◽  
Jen Hua Ling ◽  
Zuhairi Abd Hamid ◽  
Mohd Hanim Osman ◽  
Shahrin Mohammad ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Failure Modes ◽  
Ultimate Load ◽  
Precast Concrete ◽  
Tensile Load ◽  
Test Results ◽  
Steel Bars ◽  
Embedment Length ◽  
Bar Diameter

This paper presents the test results of proposed grouted sleeve connections under increasing tensile load. The objective of this research was to investigate splice connections that could provide tensile strength similar to the full tensile strength of the connected rebars. The parameters varied were splice types, splice length and rebar embedment length. The performance of the splice connection was evaluated based on the load-displacement, ultimate load, displacements and failure modes. The results show that the strength of splice connection depends on the bond strength between sleeve-to-grout and grout-to-rebar; the tensile strength of spliced steel bars and also the tensile strength of sleeve. It is observed that when the grout compressive strength is more than 60N/mm2and bar embedded length is at least 10 bar diameter, the splice connection in BS series is able to provide full tensile strength of the connected rebars.

Dynamic Energy Absorption Performances of Rain Forest Vehicle (RFV) under Frontal Impact

2014 ◽  
Vol 69 (3) ◽  
Author(s):  
M. S. Othman ◽  
Z. Ahmad
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Impact Loading ◽  
Rain Forest ◽  
Experimental Testing ◽  
Rigid Wall ◽  
Crash Analysis ◽  
Frontal Impact ◽  
Frontal Section ◽  
The Impact

This paper treats the crash analysis and energy absorption response of Rain Forest Vehicle (RFV) subjected to frontal impact scenario namely impacting rigid wall and column. Dynamic computer simulation techniques validated by experimental testing are used to carry out a crash analysis of such vehicle. The study aims at quantifying the energy absorption capability of frontal section of RFV under impact loading, for variations in the load transfer paths and geometry of the crashworthy components. It is evident that the proposed design of the RFV frontal section are desirable as primary impact energy mitigation due to its ability to withstand and absorb impact loads effectively. Furthermore, it is found that the impact energy transmitted to the survival room may feasibly be minimized in these two impact events. The primary outcome of this study is design recommendation for enhancing the level of safety of the off-road vehicle where impact loading is expected.   

Low-velocity impact response of wood-strand sandwich panels and their components

Holzforschung ◽  
2018 ◽  
Vol 72 (8) ◽  
pp. 681-689 ◽  
Author(s):  
Mostafa Mohammadabadi ◽  
Vikram Yadama ◽  
LiHong Yao ◽  
Debes Bhattacharyya
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Failure Modes ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Insulation Material ◽  
Low Velocity ◽  
Velocity Impact ◽  
Section Modulus ◽  
The Impact

AbstractProfiled hollow core sandwich panels (SPs) and their components (outer layers and core) were manufactured with ponderosa and lodgepole pine wood strands to determine the effects of low-velocity impact forces and to observe their energy absorption (EA) capacities and failure modes. An instrumented drop weight impact system was applied and the tests were performed by releasing the impact head from 500 mm for all the specimens while the impactors (IMPs) were equipped with hemispherical and flat head cylindrical heads. SPs with cavities filled with a rigid foam insulation material (SPfoam) were also tested to understand the change in EA behavior and failure mode. Failure modes induced by both IMPs to SPs were found to be splitting, perforating, penetrating, core crushing and debonding between the core and the outer layers. SPfoams absorbed 26% more energy than unfilled SPs. SPfoams with urethane foam suffer less severe failure modes than SPs. SPs in a ridge-loading configuration absorbed more impact energy than those in a valley-loading configuration, especially when impacted by a hemispherical IMP. Based on the results, it is evident that sandwich structure is more efficient than a solid panel concerning impact energy absorption, primarily due to a larger elastic section modulus of the core’s corrugated geometry.

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