scholarly journals Failure Modes of a Reticulated Dome in a Small Airplane Crash

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
L. Lin ◽  
Y. X. Ren ◽  
M. Y. Huang ◽  
X. D. Zhi ◽  
D. Z. Wang
Keyword(s):  
Failure Modes ◽  
Impact Resistance ◽  
Test Subject ◽  
Engineering Research ◽  
Airplane Crash ◽  
Reticulated Domes ◽  
Small Airplanes ◽  
Span 60 ◽  
The Impact ◽  
Roof Sheathing

Since the 9/11 incident, many engineering research works have been conducted on the impact resistance of large-span space structures. In the present study, a small airplane, Bombardier Challenger 850, was chosen as the test subject. An airplane crash on a single-layered Kiewitt-8 reticulated dome with span 60 m considering roof sheathing effect was simulated using ANSYS/LS-DYNA software. The principles of establishing the numerical model of small airplanes were determined. In addition, the impact styles of small airplane and impact positions on the dome were investigated. The failure modes of reticulated dome with roof sheathing due to small airplane crash were identified. Furthermore, the failure modes between reticulated domes with and without roof sheathing were compared and the effect of roof sheathing on the failure modes of reticulated dome under a small airplane crash was investigated.

Experimental and Numerical Study of Basalt FRP Strip Strengthened RC Slabs under Impact Loads

2020 ◽  
Vol 20 (06) ◽  
pp. 2040001 ◽  
Author(s):  
Wensu Chen ◽  
Thong M. Pham ◽  
Mohamed Elchalakani ◽  
Huawei Li ◽  
Hong Hao ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Numerical Study ◽  
Impact Resistance ◽  
Basalt Fiber ◽  
Impact Behavior ◽  
Impact Loads ◽  
Quantitative Measurements ◽  
Rc Slabs ◽  
The Impact

Basalt fiber-reinforced polymer (BFRP) has been applied for strengthening concrete structures. However, studies on reinforced concrete (RC) slabs strengthened by BFRP strips under impact loads are limited in open literature. This study investigates the efficiency of using BFRP strips with various strengthening layouts and anchoring schemes on the impact resistance of RC slabs. A total of 11 two-way square slabs were prepared and tested, including one reference specimen without strengthening and ten slabs strengthened with BFRP strips and/or anchors. The RC slabs were impacted by a drop weight with increasing height until slab failure. The observed failure modes include punching shear failure, BFRP sheet debonding and reinforcement fracture. The failure modes and the effects of using various strengthening schemes on the impact resistant capacity of RC slabs were examined. The quantitative measurements, such as impact velocity, indentation depth and diameter, were compared and discussed. In addition, numerical studies were carried out by using LS-DYNA to simulate the impact tests of RC slabs with and without BFRP strengthening. With the calibrated numerical model, the impact behavior of slabs with various dimensions and strengthening layouts under different impact intensities can be predicted with good accuracy.

Dynamic Response of Reticulated Domes under the Impact

2014 ◽  
Vol 638-640 ◽  
pp. 58-61
Author(s):  
Chang Wu ◽  
Xiu Li Wang ◽  
Ya Xiong Liang ◽  
Zhan Zhong Yin
Keyword(s):  
Dynamic Response ◽  
Failure Modes ◽  
Numerical Models ◽  
Single Layer ◽  
Response Mode ◽  
Object Size ◽  
Response Modes ◽  
Reticulated Domes ◽  
Parametric Analyses ◽  
The Impact

As the study of the dynamic response of single-layer reticulated domes under impact, Numerical models for single-layer Kiewitt-6 reticulated domes with sub steel cube column were established by the ANSYS/ LS-DYNA program and a dynamic analysis were carried out. Four failure modes for the reticulated domes were put forward according as the dynamic response and plastic deformation. The parametric analyses on the dynamic response of single-layer reticulated domes with sub steel cube column under the impact loading are carried out, by changing the impact velocity, mass of impact object, size of impact object and impact location.The effects of these parameters on the response mode of the structures are investigated, and the distribution regularity of the response modes of the structures with different parameters is explained.

Impact performances and failure modes of glass fiber reinforced polymers in different curvatures and stacking sequences

2021 ◽  
pp. 002199832110590
Author(s):  
Cihan Kaboglu ◽  
Taha Y Eken ◽  
Yakup Yurekturk
Keyword(s):  
Glass Fiber ◽  
Failure Modes ◽  
Impact Resistance ◽  
Matrix Cracking ◽  
Fiber Reinforced ◽  
Stacking Order ◽  
Glass Fiber Reinforced ◽  
The Impact

Recently, glass fiber reinforced polymer composites have been increasingly used in applications which are exposed to impact loads due to their high strength, low weight, and corrosion resistance properties. Therefore, the effect of curvature of composite laminate on their impact resistance is important. In this study, the mechanical properties of three curvature diameters and two stacking sequences, which have not been compared before, were examined and compared. The diameter of curved composites is 760 mm, 380 mm, and 304 mm and flat designated as A, B, C, and D, respectively. The fiber stacking orders are [0/0/-45/+45/90/90]S and [90/90/-45/+45/0/0]S designated as Type 1 and Type 2, respectively. The drop-weight impact tests were performed and failure modes of composites were examined. It was observed that the impact resistance decreases with the increase of curvature, where 760 mm diameter and Type 2 composites had the highest strength in all of the composites. In addition, delamination, fiber breakage, and matrix cracking failure modes were observed in the composites after impact. The reason why the strength decreases as the curvature of the composite increases is that the curved areas create an effect that increases the external force applied. The reason why Type 2 stacking order is more durable than Type 1 stacking order is that the 90° fiber direction in the bottom layer has a damping effect on the applied force. According to the results of this study, composite materials with larger diameter and stacking order starting with 0° provides more mechanical strength. [Formula: see text]

Experimental Study on Impact Resistance of CaCO3 Whisker-Reinforced Cement Mortar

2011 ◽  
Vol 99-100 ◽  
pp. 706-710
Author(s):  
Ming Li Cao ◽  
Hang Yao ◽  
Shi Cai Cui
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Cement Mortar ◽  
Impact Load ◽  
Impact Resistance ◽  
Reinforcing Effect ◽  
Reinforced Cement ◽  
The Impact

CaCO3 whiskers were incorporated into the cement mortar in this study and the effects of whiskers on the impact resistance of mortar were investigated. The results showed that CaCO3 whiskers could improve the impact resistance of cement mortar before initial cracking. When the whisker content was 10%, the reinforcing effect was optimal. But after initial cracking, the capacity of matrix to resist further impact load was not improved significantly. By observing the failure modes of specimens, it was shown that the crack branches of whisker-reinforced cement mortar were increased, which indicated the brittleness of matrix was decreased and the toughness was improved to some extent. In addition, the reinforcing mechanisms of CaCO3 whiskers in the cement mortar were also discussed

Quasi-Static Impact Response of Alternative Origami-Core Sandwich Panels

2013 ◽  
Author(s):  
Joseph M. Gattas ◽  
Zhong You
Keyword(s):  
Failure Modes ◽  
Mechanical Performance ◽  
Sheet Material ◽  
Preliminary Investigation ◽  
Impact Resistance ◽  
Sandwich Panels ◽  
Experimental Models ◽  
Lateral Impact ◽  
Energy Absorbing ◽  
The Impact

Foldcore sandwich panels have been the focus of much recent study in the aerospace industry. Existing foldcores are composed of a partially folded Miura origami pattern sandwiched between two stiff facings, and have been shown to possess numerous useful properties for impact-resistant applications. Non-Miura origami pattern with similar geometric properties, specifically rigid-foldability and tessellation, may be used as potential alternative origami-cores for sandwich panels, however the mechanical performance of such cores remains an unexplored area. This paper conducts a preliminary investigation into the impact resistance of five non-Miura sandwich panels. The selected patterns are numerically analysed under quasi-static lateral impact loads, and comparisons are drawn with existing foldcore designs. Two particular patterns are found to have failure modes suited for energy-absorbing applications. Prototypes of these two cores are constructed from polypropylene sheet material and experimentally tested to validate numerical results. Reasonable correlation is seen in the force-displacement response of numerical and experimental models.

Role of Size of Rubber Particles on Failure Mode and Impact Resistance Characteristics of PC/ABS Blends and their ABS Constituents with a Higher Rubber Content

2020 ◽  
Vol 402 ◽  
pp. 1-6
Author(s):  
Muhammad Nizar Machmud ◽  
Masaki Omiya ◽  
Hirotsugu Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Impact Test ◽  
Rubber Particle ◽  
Impact Resistance ◽  
Acrylonitrile Butadiene Styrene ◽  
Rubber Content ◽  
System A ◽  
The Impact

This study presents an experimental study on failure modes and resistances of polycarbonate (PC)/Acrylonitrile Butadiene Styrene (ABS) blends and their ABS constituents under a drop weight impact test (DWIT). Failure modes and impact resistances such as impact strength and impact toughness of such blends are generally influenced by molecular weight of the PC, rubber content and size of rubber particle in ABS system. A preliminary study on ABS materials using a DWIT showed that size of rubber particle not only determined their failure modes but also influencing their resistance characteristics. However, in a previous study performed using the similar DWIT on PC/ABS blends with a 10 wt% rubber content, it was revealed that size of rubber particle did not significantly influence their resistances. Their failure modes were even macroscopically very difficult to be distinguished. This study, hence, is aimed to further explore role of the size of rubber particle on failure mode and impact resistance characteristics of the PC/ABS blends and their ABS constituents with a higher rubber content. The impact test results have revealed that with a 20 wt% rubber content, size of rubber particle only influenced the resistances of the PC/ABS blends. It did not significantly contribute to affect failure mode of the PC/ABS blends. Whilst, it significantly influenced failure modes and resistances of the ABS. The DWIT results also re-confirmed that blending a brittle ABS into PC led to produce a tougher PC/ABS blend.

Failure Modes for Single-Layer Reticulated Domes under Oblique Impact

2012 ◽  
Vol 166-169 ◽  
pp. 1284-1289
Author(s):  
Duo Zhi Wang ◽  
Feng Fan ◽  
Jun Wu Dai ◽  
Xu Dong Zhi ◽  
Zhenggang Cao ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Numerical Simulations ◽  
Failure Modes ◽  
Single Layer ◽  
Oblique Impact ◽  
Large Numbers ◽  
Impact Position ◽  
Global Collapse ◽  
Reticulated Domes ◽  
The Impact

FE models of both the single-layer Kiewitt-8 reticulated domes with a span of 60m and the cylindrical impactor were developed incorporating ANSYS/LS-DYNA. Afterward, fourteen groups impact are simulated by changing the impact position or impacted angle on reticulated dome, and impact velocity and mass of impactor are changed for each group impact. On the basis of large numbers of numerical simulations, characteristics of dynamic response for reticulated dome under impact are shown. And four failure modes (Members slightly damaged, Local collapse of dome, Global collapse of dome, Members shear failed) are presented for single-layer Kiewitt-8 reticulated dome under diverse impact. The distributing of failure modes for the fourteen types impact are different from each other, and the adverse position and angle are summrized.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2323
Author(s):  
Yubing Du ◽  
Zhiqing Zhao ◽  
Qiang Xiao ◽  
Feiting Shi ◽  
Jianming Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Size Effect ◽  
Compressive Stress ◽  
Failure Modes ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Substitution Ratio ◽  
The Impact

To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.

scholarly journals Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Copper Foil ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Lightning Strike ◽  
Single Wall Carbon Nanotubes ◽  
Carbon Fibre Reinforced Polymer ◽  
The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

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