Impact to Composite Box Containing Water and Baffles

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Y. W. Kwon ◽  
T. J. South ◽  
K. J. Yun
Keyword(s):  
Experimental Study ◽  
Water Level ◽  
Computational Study ◽  
Structural Response ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Front Side ◽  
Low Velocity ◽  
Structural Responses ◽  
The Impact

A series of experimental tests were conducted for low-velocity impact on a composite box containing water in order to study the fluid–structure interaction (FSI). Then, baffles were inserted in the box to examine their effect on the structural response of the composite box. Finally, a computational study was conducted to supplement the experimental study. The water level inside the composite box was varied incrementally from 0% (i.e., no water) to 100% (full water). The impact velocity was also changed. In the experimental study, strain gauges and the load cell were used to measure the strain responses at the front, side, and back surfaces as well as the impact force. The results showed that the FSI effect was significant to the structural responses depending on the water level. The effect of the baffle was different among the front, side, and back surfaces. Both experimental and numerical results agreed well.

A Hierarchical Impact Force Reconstruction Method for Aerospace Composites

2019 ◽  
Vol 812 ◽  
pp. 17-24
Author(s):  
Mario Emanuele de Simone ◽  
Francesco Ciampa ◽  
Michele Meo
Keyword(s):  
Impact Force ◽  
Research Work ◽  
Time History ◽  
Low Velocity Impact ◽  
Reconstruction Method ◽  
Low Velocity ◽  
Force Reconstruction ◽  
Structural Responses ◽  
High Level ◽  
The Impact

This research work presents a hierarchical method able to reconstruct the time history of the impact force on a composite wing stringer-skin panel by using the structural responses measured by a set of surface bonded ultrasonic transducers. Time reversal method was used to identify the impact location by the knowledge of structural responses recorded from a set of excitation points arbitrarily chosen on the plane of the structure. Radial basis function interpolation approach was then used to calculate the transfer function at the impact point and reconstruct the impact force history. Experimental results showed the high level of accuracy of the proposed impact force reconstruction method for a number of low-velocity impact sources and energies.

The Effect of the Impactor Diameter and Boundary Conditions on Low Velocity Impact Composites Behaviour

2007 ◽  
Vol 7-8 ◽  
pp. 217-222 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
A.G. Magalhães ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Boundary Conditions ◽  
Damage Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of the impactor diameter and boundary conditions on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular plates were tested under low velocity impacts for two diameters of the hemispherical impactor, 12.7 mm and 20 mm, and considering similar impact energies, 2.6 J for the first impactor and 3 J for the second one. Rectangular and square plates were analysed under low velocity impacts with different boundary conditions. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements including a cohesive mixed-mode damage model, which allows to model delamination between layers. The impact tests showed that both the impactor’s diameter and boundary conditions have influence on the delaminated area. Good agreement between experimental and numerical analysis for shape, orientation and size of damage was obtained.

Elastic Impact of Abrasives for Controlled Erosion in Fine Finishing of Surfaces

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
V. S. Sooraj ◽  
V. Radhakrishnan
Keyword(s):  
Experimental Study ◽  
Erosive Wear ◽  
Target Surface ◽  
Low Velocity Impact ◽  
Surface Finishing ◽  
Low Velocity ◽  
Elastic Impact ◽  
Impact Theory ◽  
Proposed Modification ◽  
The Impact

Finishing of surfaces using free abrasive impingement is one of the constructive applications of erosive wear, well suited for complex shaped engineering components with difficult-to-access surfaces. Low velocity impact of abrasives in a fluidized bed is reported as a promising choice to impart fine finish on the target surface. An improved methodology to control the erosion and to achieve ultra fine finish through elastic impact of abrasives, using a carrier type-fluidized abrasive finishing, is discussed in this paper. Using the basic concepts of impact theory and contact mechanics, a revised mathematical model to express the depth of erosion as a function of material properties of target and erodent is proposed. Modification in erodent abrasive to introduce an elastic nature to the impact is described in detail using the theoretical model. This is substantiated through a particle-dropping experimental study. The effect of multiple impacts in a practical situation is also discussed through a detailed experimental study, clearly demonstrating the concepts of elastic impact erosion for surface finishing.

scholarly journals Investigation of damage to thick composite laminates under low-velocity impact and frequency-sweep vibration loading conditions

2020 ◽  
Vol 12 (10) ◽  
pp. 168781402096504
Author(s):  
Miaomiao Duan ◽  
Zhufeng Yue ◽  
Qianguang Song
Keyword(s):  
Composite Laminates ◽  
Energy Levels ◽  
Experimental Tests ◽  
Element Model ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Internal Damage ◽  
Frequency Sweep ◽  
Velocity Impact ◽  
The Impact

A detailed investigation of damage and failure mechanisms of composite laminates under low-velocity impact (LVI) by experimental tests and numerical modeling is presented. Five impact energy levels were investigated on composite laminates by drop-weight tests. Permanent indentations were measured, and delamination areas of each interface induced by each LVI event were captured using an ultrasonic C-scan. The 3D volume elements with a user-defined, material-based finite element model (FEM) has been applied to predict the LVI event considering damage modes, including intra-ply damage and inter-ply damage. The results of the FEM were found to agree well with experimental observations. Internal damage of the laminate during the impact process was analyzed. For thick laminates, the initiation of damage is observed at the first layer, and then spreads from the impact surface to the back, leading to a pine-type damage pattern as the thickness increases. Frequency-sweep vibration tests of composite laminates subjected to LVI events were studied under a “fixed ends” boundary condition. Our results show that it is reasonable to use frequency-sweep vibration experiments to evaluate the damage of laminates subjected to LVI events.

Evaluation of Low Velocity Impact Response of Carbon Fiber Reinforced Composites

2018 ◽  
Vol 779 ◽  
pp. 3-10
Author(s):  
Mihaela Raluca Condruz ◽  
Alexandru Paraschiv ◽  
Ionuț Sebastian Vintilă ◽  
Mihail Sima ◽  
Andreea Deutschlander ◽  
...  
Keyword(s):  
Polymeric Composite ◽  
Experimental Tests ◽  
Impact Testing ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Specimen Thickness ◽  
Fiber Reinforced ◽  
Low Velocity ◽  
Cfrp Laminates ◽  
The Impact

The analysis of damage resulted from concentrated out-of-plane impact forces is a concern in case of fiber reinforced polymeric composite aerostructures. Thereby, it can be quantified in terms of resulting size/damage type by drop weight impact testing. The aim of the present research was to evaluate the impact response of CFRP laminates by FEA and experimental tests. For FEA, two failure criterions were used, energetic criterion and Tsai Wu criterion. In both modeling scenarios the laminate was fractured. In case of the energetic criterion it was observed a meandering crack along with internal delamination of the material plies, while in case of the Tsai Wu criterion the impactor passes through the specimen, destroying the impacted area. Experimental tests performed at 0.7 meters height and 33 J of impact energy showed that all material plies were visible damaged, but the impactor didn’t pass through all specimen thickness. Different damage modes were observed on the tested specimens, the impacted face of the specimen presented a combined damage consisting in large cracks with fiber breakage indentation/puncture and a dent while on the non-impacted side of the specimen splits, cracks and a small swelling were observed. Considering the results from FEA and experimental tests, it can be said that regarding the damage shape, the experimental results are in a good agreement with a combination of the results obtained from the two failure models of FEA.

The Dynamic Response of the Clamped Beam under Low Velocity Impact

2011 ◽  
Vol 328-330 ◽  
pp. 1017-1021
Author(s):  
Wen Gui Long ◽  
Zhu Hua Tan ◽  
Yang Liu ◽  
Fu Rui Wang
Keyword(s):  
Theoretical Model ◽  
Dynamic Response ◽  
Virtual Work ◽  
Plastic Hinge ◽  
Structural Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact ◽  
Good Agreement

A simplified theoretical model about the impact energy and maximum deflection was acquired based on the principle of virtual work while clamped beam subjected to low velocity impact. Finite element simulations have been undertaken to further understand the response of the clamped beam, the results show that: A good agreement has been obtained between theoretical model and numerical results, the dynamic response of the clamped beam is divided into four stages: elastic fluctuation, the overall structural response, unloading response and free vibration, the formation of plastic hinge occurred in the overall structural response stage.

Residual Strength after Low Velocity Impact in Carbon-Epoxy Laminates

2006 ◽  
Vol 514-516 ◽  
pp. 624-628 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Residual Strength ◽  
Testing Machine ◽  
Experimental Tests ◽  
Low Energy ◽  
Low Velocity Impact ◽  
Stacking Sequence ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of low energy impacts on residual strength of carbon-epoxy laminates. Experimental tests were performed on [0,90,0,90]2s and [0,90]8 laminates using a drop weight-testing machine. The influence of the laminate stacking sequence is analysed under 1.5 J, 2 J, 2.5 J and 3 J impact energies, corresponding to a 0.91 ms-1, 1.05 ms-1, 1.18 ms-1 and 1.29 ms-1 of impact velocity, respectively. The impacted plates were inspected by CScan to evaluate the size, shape and position of the delaminations through the thickness of the plate. The same plates were inspected by C-Scan before the impact, to evaluate the eventual presence of defects produced during the manufacturing process. The residual flexural strength showed that the [0,90,0,90]2s laminates have better performance than the [0,90]8 ones. The explanation is related with the lower flexural stiffness of the antisymmetric lay-up relatively to the symmetric one.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

2020 ◽  
pp. 095440622097542
Author(s):  
Jianxun Du ◽  
Peng Hao ◽  
Mabao Liu ◽  
Rui Xue ◽  
Lin’an Li
Keyword(s):  
Honeycomb Structure ◽  
Low Velocity Impact ◽  
Parameter Study ◽  
Low Velocity ◽  
Micro Aerial Vehicle ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Aerial Vehicle ◽  
Thin Walled ◽  
The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

Sign in / Sign up

Export Citation Format

Share Document