Impact Toughness of Closed-Cell Aluminum Foam

2018 ◽  
Vol 933 ◽  
pp. 203-208
Author(s):  
Yong Liang Mu ◽  
Ding Ding Wang ◽  
Yong Dong He ◽  
Guang Chun Yao
Keyword(s):  
Impact Toughness ◽  
Aluminum Foam ◽  
Impact Load ◽  
Peak Load ◽  
Load History ◽  
Notched Specimens ◽  
State Of Stress ◽  
Closed Cell ◽  
The Impact ◽  
Rupture Mode

The impact toughness of closed-cell aluminum foam with various densities was investigated. The impact load history revealed an elastic region followed by a rapid load drop region. The peak load and impact toughness of aluminum foam increases exponentially with density. The power exponents for impact toughness test are greater than that for compressive test. Fracture analysis indicated a mixed-rupture mode of quasi-cleavage and small shallow dimples. It can be attributed to the complex state of stress of notched specimens and elevated impact velocity under impact loading.

Effects of Wall Thickness and Crush Initiators Position under Experimental Drop Test on Square Tubes

2017 ◽  
Vol 865 ◽  
pp. 612-618 ◽  
Author(s):  
M. Malawat ◽  
Jos Istiyanto ◽  
D.A. Sumarsono
Keyword(s):  
Energy Absorption ◽  
Tube Wall ◽  
Impact Load ◽  
Peak Load ◽  
Load Force ◽  
Drop Height ◽  
Thin Walled ◽  
The Impact ◽  
Initial Peak ◽  
Load Mass

Crush initiators are the weakest points to reduce initial peak load force with significant energy absorption ability. The objective of this paper is to study the effects of square tube thickness and crush initiators position for impact energy absorber (IEA) performance on thin-walled square tubes. Two square tubes having thickness about 0.6 mm (specimen code A) and 1 mm (specimen Code C) were tested under dynamic load. The crushing initiator is designed around the shape of the tube wall and has eight holes with a fixed diameter of 6.5 mm. In the experiment, the crushing initiator was determined at 5 different locations on the specimen wall. These locations are 10 mm, 20 mm. 30 mm, 40 mm, and 50 mm measured from the initial collision position of the specimen tested. The impact load mass was about 80 kg and had a drop height of about 1.5 m. Using the simulation program of the LabVIEW Professional Development System 2011 and National Instrument (NI) 9234 software equipped with data acquisition hardware NI cDAQ-9174 the signal from the load cell was sent to a computer. By controlling the thickness of the thin-walled square tube, the peak loading force can be decreased by approximately 56.75% and energy absorption ability of IEA can be increased approximately to 11.83%. By using different thin-walled square tube can produce different best crush initiators position with the lowest peak load force.

The relation between the impact load history and the impacted point on a cantilever beam.

1986 ◽  
Vol 52 (477) ◽  
pp. 1423-1428
Author(s):  
Hiroyuki MATSUMOTO ◽  
Toyomi MIYAGAWA ◽  
Sadayuki UJIHASHI ◽  
Dong-Yul YANG
Keyword(s):  
Cantilever Beam ◽  
Impact Load ◽  
Load History ◽  
The Impact

scholarly journals Study on Concrete Pier Impact Performance after Implementing Equal Cross-Section Stainless Steel with Protection from Closed-Cell Aluminum Foam

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xiwu Zhou ◽  
Honglong Zhang ◽  
Wenchao Zhang ◽  
Guoxue Zhang
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
Aluminum Foam ◽  
Bridge Piers ◽  
Concrete Bridge ◽  
Reinforced Concrete Bridge ◽  
Impact Forces ◽  
Closed Cell ◽  
Steel Bars ◽  
The Impact

In the present study, in order to examine the impact performances of ordinary reinforced concrete bridge piers which have been replaced by stainless-steel bars of equal cross-sections under the protective condition of anticollision material, the impact dynamic responses of the ordinary reinforced concrete bridge piers, with replacements under the protection of closed-cell aluminum foam, were compared and analyzed using an ultrahigh drop hammer impact test system. The results showed that when the impact velocity was small (for example, less than 1.42 M/s), after the implementation of equal cross-sectional replacements, the closed-cell aluminum foam had been in an elastic or yield stage. During that stage, the impact forces of the stainless-steel reinforced concrete piers were larger than those of the ordinary reinforced concrete piers, and the relative ratios were stable at approximately 28 to 34%. In addition, the relative ratios of the displacements at the tops of the components were also found to be stable at approximately 22%, and the change rates of the concrete ultrasonic damages were approximately the same. However, when the impact forces had increased (for example, more than 1.67 m/s), the closed-cell aluminum foam entered a densification stage, and the peak impact force ratios decreased sharply. It was also observed that the relative peak displacement ratios at the tops of the components displayed increasing trends, and the change rates of the concrete ultrasonic damages had displayed major flux. Therefore, the replacement of the ordinary piers with stainless-steel bars had increased the possibility of shear failures.

scholarly journals Torsion Property of the Structure Bonded Aluminum Foam Due to Impact

2017 ◽  
Vol 62 (2) ◽  
pp. 1353-1357
Author(s):  
G.W. Hwang ◽  
J.U. Cho
Keyword(s):  
Impact Energy ◽  
Aluminum Foam ◽  
Bonding Interface ◽  
Cell Type ◽  
Aluminum Foams ◽  
Fracture Characteristics ◽  
Foaming Agent ◽  
Closed Cell ◽  
The Impact ◽  
Torsion Property

AbstractAn aluminum foam added with foaming agent, is classified into an open-cell type for heat transfer and a closed-cell type for shock absorption. This study investigates the characteristic on the torsion of aluminum foam for a closed-cell type under impact. The fracture characteristics are investigated through the composite of five types of aluminum foam (the thicknesses of 25, 35, 45, 55 and 65 mm), when applying the torsional moment of impact energy on the junction of a porous structure attached by an adhesive. When applying the impact energy of 100, 200 and 300J, the aluminum foams with thicknesses of 25 mm and 35 mm broke off under all conditions. For the energy over 200J, aluminums thicker than 55 mm continued to be attached. Furthermore, the aluminum specimens with thicknesses of 55 mm and 65 mm that were attached with more than 30% of bonding interface remained, proving that they could maintain bonding interface against impact energy. By comparing the data based on the analysis and test result, an increase in the thickness of specimen leads to the plastic deformation as the stress at the top and bottom of bonding interface moves to the middle by spreading the stress horizontally. Based on this fracture characteristic, this study can provide the data on the destruction and separation of bonding interface and may contribute to the safety design.

Effect of the Impact Load on Joining Region of the Friction Stir Jointing for 7022 Aluminum Alloy

2013 ◽  
Vol 568 ◽  
pp. 21-24
Author(s):  
Hong Feng Wang ◽  
J.L. Wang ◽  
W.W. Song ◽  
Dun Wen Zuo ◽  
X.L. Duan
Keyword(s):  
Aluminum Alloy ◽  
Impact Toughness ◽  
Base Metal ◽  
Process Parameters ◽  
Rotation Speed ◽  
Impact Load ◽  
Feed Speed ◽  
Friction Stir ◽  
The Impact ◽  
Joining Process

The impact experiment of the joining workpiece of the friction stir jointing for 7022 aluminum alloy was made by the impact load experiment machine. The objective was studying the effect of the different joining process parameters of the FSJ on impact toughness. The results showed the impact toughness of the joining region was lower than that of the base metal when the rotation speed of the tool was 300rpm and the feed speed was 30 and 50mm•min-1, the impact toughness of the joining region of the other joining process parameters was higher than that of the base metal. The impact toughness of the joining region was the best when the rotation speed of the tool was 400rpm and the feed speed was 100mm•min-1. It is higher than 22.3% of the base metal. The impact fracture of the joining region was mainly dimple; only fracture edge appeared a small amount of the quasi cleavage. The fracture presented good toughness.

scholarly journals Influence of the stacking sequence on the low-energy impact resistance of flax/PA11 composite

2019 ◽  
Vol 53 (22) ◽  
pp. 3187-3198 ◽  
Author(s):  
Yann Lebaupin ◽  
Thuy-Quynh T Hoang ◽  
Michaël Chauvin ◽  
Fabienne Touchard
Keyword(s):  
Impact Load ◽  
Peak Load ◽  
Composite Plates ◽  
Low Energy ◽  
Impact Behavior ◽  
Stacking Sequence ◽  
Polyamide 11 ◽  
Energy Impact ◽  
Isotropic Composite ◽  
The Impact

In this paper, the low-energy impact behavior of a fully biobased composite made of bio-sourced polyamide 11 resin reinforced with flax fibers was investigated. Different composite laminates were studied in order to determine the stacking sequence effects on the impact behavior of these composites. Four stacking sequences were manufactured: unidirectional [0°]8, cross-ply [0°/90°]2s, sandwich-like [02°/902°]s and quasi-isotropic [45°/0/−45°/90°]s. A low impact energy of 3.6 J was applied on these laminates by means of a drop weight impact tower. The impact properties of these lay-ups were ascertained by analysing the impact load history, the maximal displacement of the impactor and the absorbed energy. Damage after impact was further assessed by visual inspections, topographic measurements, C-scan and X-ray micro-tomography observations. The results show that impact damage of composite plates is highly influenced by fiber orientation. The impact test data are in good agreement with damage analysis after impact and indicate that stacking plies in the same orientation lead to a larger induced damage, which is responsible for energy dissipation. The quasi-isotropic composite has the smallest induced damage and the highest peak load. Otherwise, the sandwich-like sequence shows the lowest peak load, the highest energy absorption and significant induced damage. Therefore, it is necessary to choose the most suitable lay-up, in terms of impact behavior, for each considered industrial application.

Experimental Investigation on the Crashworthiness of Braided Glass/Epoxy Tubes Subjected to Axial Impacting

2014 ◽  
Vol 23 (2) ◽  
pp. 096369351402300
Author(s):  
Ping Zhang ◽  
Liang-Jin Gui ◽  
Zi-Jie Fan ◽  
Jing-Yu Liu
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Failure Modes ◽  
Impact Load ◽  
Peak Load ◽  
Low Velocity Impact ◽  
Test Results ◽  
Specific Energy Absorption ◽  
The Mean ◽  
The Impact

This paper presented an experimental study on the low-velocity impact response of triaxial braided composite circular tubes, which were fabricated with S-glass/epoxy composite. The impact responses were recorded and analyzed in terms of impact load-displacement curves and specific energy absorption. In addition, four basic failure modes called delaminating, splaying, fragmental fracture and progressive folding were founded. The levels of the mean impact load and specific energy absorption (SEA) are determined by the energy absorption mechanisms, which are related to the dominant failure modes of the tubes. In general, delamination which exhibits the poor energy absorbing performance is the dominant failure mode for all the specimens. Impact test results showed that all three types of tubes had almost the same SEA. Compared to the quasi-static test results, the first peak load and the mean load decrease at about 50% and 10% respectively, SEA generally decreases at an average level 10%.

On the Distribution of Wave Impact Loads on Offshore Structures

2017 ◽  
Author(s):  
Thomas B. Johannessen ◽  
Øystein Lande ◽  
Øistein Hagen
Keyword(s):  
Model Test ◽  
Load Distribution ◽  
Impact Load ◽  
Peak Load ◽  
Offshore Structures ◽  
Impact Loads ◽  
Test Results ◽  
Wave Impact ◽  
The Impact ◽  
Crest Height

For offshore structures in harsh environments, horizontal wave impact loads should be taken into account in design. Shafts on GBS structures, and columns on semisubmersibles and TLPs are exposed to impact loads. Furthermore, if the crest height exceeds the available freeboard, the deck may also be exposed to wave impact loads. Horizontal loads due to waves impacting on the structure are difficult to quantify. The loads are highly intermittent, difficult to reproduce in model tests, have a very short duration and can be very large. It is difficult to calculate these loads accurately and the statistical challenges associated with estimating a value with a prescribed annual probability of occurrence are formidable. Although the accurate calculation of crest elevation in front of the structure is a significant challenge, industry has considerable experience in handling this problem and the analysis results are usually in good agreement with model test results. The present paper presents a statistical model for the distribution of horizontal slamming pressures conditional on the incident crest height upwave of the structure. The impact load distribution is found empirically from a large database of model test results where the wave impact load was measured simultaneously at a large number of panels together with the incident crest elevation. The model test was carried out on a circular surface piercing column using long simulations of longcrested, irregular waves with a variety of seastate parameters. By analyzing the physics of the process and using the measured crest elevation and the seastate parameters, the impact load distribution model is made seastate independent. The impact model separates the wave impact problem in three parts: – Given an incident crest in a specified seastate, calculate the probability of the crest giving a wave impact load above a threshold. – Given a wave impact event above a threshold, calculate the distribution of the resulting peak load. – Given a peak load, calculate the distribution of slamming pressures at one spatial location. The development of the statistical model is described and it is shown that the model is appropriate for fixed and floating structures and for wave impact with both columns and the deck box.

scholarly journals Effect of Fibre Architecture on Impact Response of Glass-Aluminium Fibres Metal Laminates (FML)

2019 ◽  
Vol 9 (1) ◽  
pp. 5639-5645
Keyword(s):  
Glass Fibre ◽  
Impact Load ◽  
Peak Load ◽  
Matrix Cracking ◽  
Impact Behavior ◽  
Drop Weight ◽  
Glass Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Weight Impact ◽  
The Impact

This paper investigates the drop weight impact behavior of glass fibre-aluminum (GFRP-AL FML) composites. The purpose of the research is to study the effect of different type of glass fibres architecture, i.e woven and unidirectional, with existence Al sheet in the middle of the glass fibre reinforced polymer composites (GFRP). The impact behaviour of these GFRP and GFRP-AL FMLs was investigated using a drop-weight impact tower at three different energy level, which are 10J, 20J and 30J. The Load - deflection curves were used to measure the absorbed energy. The results showed that the woven type of GFRP exhibited the highest peak load but lowest deflection thus reducing the total energy absorbed. In contrast, the unidirectional types of GFRP possessed the lowest peak load and highest deflection, which results in the highest energy absorbed. For the GFRP-AL FML composites, the energy absorbed obtained almost similar for both woven and unidirectional types. This is may be due to poor adhesion between the GFRP and Al sheet, thus make both materials separated and delaminated when subjected to impact load. The optical analysis proved that the GFRP-AL debonding, fibres breakage, fibres delamination and matrix cracking occurred during the impact loading. These are the main impact energy –absorption mechanisms involved during the test.

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