Transverse Impact and Tensile Behavior of the Three-Dimensional Woven Fabric Reinforced Thermoplastic Composites

2010 ◽  
Vol 129-131 ◽  
pp. 1238-1243 ◽  
Author(s):  
Wei Gou Dong ◽  
Hai Ling Song
Keyword(s):  
Composite Materials ◽  
Damage Tolerance ◽  
Three Dimensional ◽  
Thermoplastic Composite ◽  
Woven Fabric ◽  
Thermoplastic Composites ◽  
Two Dimensional ◽  
Energy Impact ◽  
Commingled Yarns ◽  
The Impact

Two forms of perform were prepared by a Glass fiber/Polypropylene fiber commingled yarn. One was a three-dimensional woven fabric with an angle-interlock structure, and another was a two-dimensional plain woven fabric laminate. The three-dimensional woven fabric reinforced thermoplastic composites(3-DWRC) and two-dimensional woven fabric reinforced thermoplastic composites(2-DWRC) were fabricated by hot-press process. The Impact and tensile performances of both 3-DWRC and 2-DWRC were examined. Compared to the 2-DWRC, the 3-DWRC have better impact properties, the energy required to initiate cracks, the threshold force of the first oscillation and maximum load increased by 41.90%, 54.41%, 38.75% respectively under the low-energy impact conditions. The tensile tests shown that the 3-DWRC presented batter fracture toughness than the 2-DWRC. The use of thermoplastic composites is growing rapidly because of their excellent properties, a high toughness and damage tolerance, short processing cycles, and the ability to be reprocessed. But thermoplastic materials usually have a difficulty to impregnate between reinforcing fibers, due to high melt polymer viscosity. It is a technology innovation that the commingled yarns composed of reinforced fibers and thermoplastic fibers are used as prepreg for thermoplastic composite materials. Because thermoplastic fiber and reinforced fiber are closely combined, which reduces distances of resin’s infiltration, this can effectively overcome the difficulties of resin’s impregnation. The commingled yarns can be woven and knitted, and can facilitate the processing of complex structural composites. Three-dimensional fabrics reinforced composites are ideal materials with excellent integrity because it is linked with yarns between layers. Its shearing strength between layers, damage tolerance and reliability are better than the two-dimensional fabric laminated composites. At present, the researches of thermoplastic materials with two-dimensional fabric reinforced structure made from commingled yarns are much more, such as manufacturing technology, material properties ,effects of process conditions on properties, relationship between structures and properties, and so on [1-8]. However, only a few studies appear in literature on the structure-property relationships of three-dimensional fabric reinforced thermoplastic composite materials made of commingled yarns [9-10]. Byun, Hyung Joon et al. [9] undertook the impact test and the tensile test on 3-D woven thermoplastic composite materials and 2-D plain woven laminate which is made by CF/PEEK mixed yarn. Dong Weiguo and Huang Gu[10] studied the porosity, tensile and bending properties on 3-D woven thermoplastic composites which make from core-spun yarn containing glass fibers and polypropylene fibers. The aim of this study was to investigate the impact behavior of and tensile properties of 3-D woven fabric thermoplastic composites made by a GF/PP commingled yarns. Attempts was made to identify the damage mode of the 3-D woven fabric thermoplastic composites under the low energy impact and tensile conditions.

Low Energy Impact Damage Detection in Laminar Thermoplastic Composite Materials by Means of Embedded Optical Fibers

2005 ◽  
Vol 494 ◽  
pp. 481-486
Author(s):  
A. Kojović ◽  
I. Živković ◽  
Lj. Brajović ◽  
D. Mitraković ◽  
R. Aleksić
Keyword(s):  
Composite Materials ◽  
Optical Fibers ◽  
Impact Damage ◽  
Charpy Impact ◽  
Optical Signal ◽  
Low Energy ◽  
Thermoplastic Composite ◽  
Woven Fabric ◽  
Energy Impact ◽  
The Impact

The possibility of applying optical fibers as sensors for investigation of real time low energy impact damage in laminar thermoplastic composite materials has been studied. For that purpose intensity based optical fibers were embedded in composite material specimens. Kevlar 129 (DuPont’s registered trade-mark for poly (p-phenylene terephthalamide)) woven fabric was used as reinforcement. Impact toughness testing by the Charpy impact pendulum was conducted in order to investigate low energy impacts. Transient intensity of optical signal during the impact, were compared with material crack initiation energy and crack propagation energy. Following this approach, development of damage in material was monitored. Obtained results show that intensity based optical fibers could be used as detectors for material damage appearance, and also, for level evaluation of its degradation caused by low energy impacts.

scholarly journals Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers

2006 ◽  
Vol 60 (7-8) ◽  
pp. 176-179
Author(s):  
Aleksandar Kojovic ◽  
Irena Zivkovic ◽  
Ljiljana Brajovic ◽  
Dragan Mitrakovic ◽  
Radoslav Aleksic
Keyword(s):  
Composite Materials ◽  
Optical Fiber ◽  
Real Time ◽  
Optical Fibers ◽  
Impact Damage ◽  
Experimental Testing ◽  
Low Energy ◽  
Thermoplastic Composite ◽  
Woven Fabric ◽  
The Impact

This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the method for comparative measurement of the resulting damage in the material. For that purpose intensity-based optical fibers were built in to specimens of composite materials with Kevlar 129 (the DuPont registered trade-mark for poly(p-phenylene terephthalamide)) woven fabric as reinforcement and thermoplastic PVB (poly(vinyl butyral)) as the matrix. In some specimens part of the layers of Kevlar was replaced with metal mesh (50% or 33% of the layers). Experimental testing was conducted in order to observe and analyze the response of the material under multiple low-energy impacts. Light from the light-emitting diode (LED) was launched to the embedded optical fiber and was propagated to the phototransistor-based photo detector. During each impact, the signal level, which is proportional to the light intensity in the optical fiber, drops and then slowly recovers. The obtained signals were analyzed to determine the appropriate method for real time damage monitoring. The major part of the damage occurs during impact. The damage reflects as a local, temporary release of strain in the optical fiber and an increase of the signal level. The obtained results show that intensity-based optical fibers could be used for measuring the damage in laminar thermoplastic composite materials. The acquired optical fiber signals depend on the type of material, but the same set of rules (relatively different, depending on the type of material) could be specified. Using real time measurement of the signal during impact and appropriate analysis enables quantitative evaluation of the impact damage in the material. Existing methods in most cases use just the intensity of the signal before and after the impact, as the measure of damage. This method could be used to monitor the damage in real time, giving warnings before fatal damage occurs.

scholarly journals An experimental and theoretical investigation of particle–wall impacts in a T-junction

2013 ◽  
Vol 727 ◽  
pp. 236-255 ◽  
Author(s):  
D. Vigolo ◽  
I. M. Griffiths ◽  
S. Radl ◽  
H. A. Stone
Keyword(s):  
Flow Direction ◽  
Three Dimensional ◽  
Stokes Number ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Viscous Boundary Layer ◽  
Particle Tracing ◽  
Two Dimensional Model ◽  
Viscous Boundary ◽  
The Impact

AbstractUnderstanding the behaviour of particles entrained in a fluid flow upon changes in flow direction is crucial in problems where particle inertia is important, such as the erosion process in pipe bends. We present results on the impact of particles in a T-shaped channel in the laminar–turbulent transitional regime. The impacting event for a given system is described in terms of the Reynolds number and the particle Stokes number. Experimental results for the impact are compared with the trajectories predicted by theoretical particle-tracing models for a range of configurations to determine the role of the viscous boundary layer in retarding the particles and reducing the rate of collision with the substrate. In particular, a two-dimensional model based on a stagnation-point flow is used together with three-dimensional numerical simulations. We show how the simple two-dimensional model provides a tractable way of understanding the general collision behaviour, while more advanced three-dimensional simulations can be helpful in understanding the details of the flow.

Enhanced Infrared Heating of Thermoplastic Composite Sheets for Thermoforming Processes

2021 ◽  
Vol 36 (1) ◽  
pp. 35-43
Author(s):  
M. Längauer ◽  
G. Zitzenbacher ◽  
C. Burgstaller ◽  
C. Hochenauer
Keyword(s):  
Steady State ◽  
Composite Materials ◽  
Mechanical Performance ◽  
Heating Time ◽  
Thermoplastic Composite ◽  
Infrared Heating ◽  
Thermoplastic Composites ◽  
Steady State Condition ◽  
Reflector System ◽  
Heating Station

Abstract Thermoforming of thermoplastic composites attracts increasing attention in the community due to the mechanical performance of these materials and their recyclability. Yet there are still difficulties concerning the uniformity of the heating and overheating of parts prior to forming. The need for higher energy efficiencies opens new opportunities for research in this field. This is why this study presents a novel experimental method to classify the efficiency of infrared heaters in combination with different thermoplastic composite materials. In order to evaluate this, different organic sheets are heated in a laboratory scale heating station until a steady state condition is reached. This station mimics the heating stage of an industrial composite thermoforming device and allows sheets to slide on top of the pre-heated radiator at a known distance. By applying thermodynamic balances, the efficiency of chosen parameters and setups is tested. The tests show that long heating times are required and the efficiency of the heating is low. Furthermore, the efficiency is strongly dependent on the distance of the heater to the sheet, the heater temperature and also the number of heating elements. Yet, using a full reflector system proves to have a huge effect and the heating time can be decreased by almost 50%.

scholarly journals A monolithic algorithm for the flow simulation of flexible flapping wings

2019 ◽  
Vol 11 ◽  
pp. 175682931984612 ◽  
Author(s):  
Tao Yang ◽  
Mingjun Wei ◽  
Kun Jia ◽  
James Chen
Keyword(s):  
Three Dimensional ◽  
Flow Simulation ◽  
Flapping Wings ◽  
Rigid Sphere ◽  
Two Dimensional ◽  
Unified Framework ◽  
Fluid Structure ◽  
A Cell ◽  
Three Dimensional Configuration ◽  
The Impact

It has been a challenge to simulate flexible flapping wings or other three-dimensional problems involving strong fluid–structure interactions. Solving a unified fluid–solid system in a monolithic manner improves both numerical stability and efficiency. The current algorithm considered a three-dimensional extension of an earlier work which formulated two-dimensional fluid–structure interaction monolithically under a unified framework for both fluids and solids. As the approach is extended from a two-dimensional to a three-dimensional configuration, a cell division technique and the associated projection process become necessary and are illustrated here. Two benchmark cases, a floppy viscoelastic particle in shear flow and a flow passing a rigid sphere, are simulated for validation. Finally, the three-dimensional monolithic algorithm is applied to study a micro-air vehicle with flexible flapping wings in a forward flight at different angles of attack. The simulation shows the impact from the angle of attack on wing deformation, wake vortex structures, and the overall aerodynamic performance.

Experimental investigation on a fully thermoplastic composite subjected to repeated impacts

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6985-7002
Author(s):  
S Boria ◽  
A Scattina ◽  
G Belingardi
Keyword(s):  
Composite Laminates ◽  
Mechanical Performance ◽  
Impact Damage ◽  
Energy Levels ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Repeated Impacts ◽  
Structural Parts ◽  
The Impact

In the last years, the spread of composite laminates into the engineering sectors was observed; the main reason lies in higher values of strength/weight and stiffness/weight ratios with respect to conventional materials. Firstly, the attention was focused on fibres reinforced with thermosetting matrix. Then, the necessity to move towards low density and recyclable solutions has implied the development of composites made with thermoplastic matrix. Even if the first application of thermoplastic composites can be found into no structural parts, the replacement of metallic structural parts with such material in areas potentially subjected to impact has become worthy of investigation. Depending on the field of application and on the design geometry, in fact, some components can be subjected to repeated impacts at localized sites either during fabrication, activities of routine maintenance or during service conditions. When composite material was adopted, even though the impact damage associated to the single impact event can be slight, the accumulation of the damage over time may seriously weaken the mechanical performance of the structure. In this overview, the capability of energy absorption of a new composite completely made of thermoplastic material was investigated. This material was able to combine two conflicting requirements: the recyclability and the lightweight. In particular, repeated impacts at low velocity, on self-reinforced laminates made of polypropylene (PP), were conducted by experimental drop dart tests. Repeated impacts up to the perforation or up to 40 times were performed. In the analysis, three different energy levels and three different values of the laminate thicknesses were considered in order to analyse the damage behaviour under various experimental configurations. A visual observation of the impacted specimens was done, in order to evaluate the damage progression. Moreover, the trend of the peak force interchanged between specimen and dart and the evolution of both the absorbed energy and of the bending stiffness with the impacts number were studied. The results pointed out that the maximum load and the stiffness of the specimens tended to grow increasing the number of the repeated impacts. Such trend is opposite compared to the previous results obtained by other researchers using thermosetting composites.

Comparison of the impact damage resistance of non-hybrid and intra-ply hybrid carbon/E-glass/polypropylene non-crimp thermoplastic composites

2018 ◽  
Vol 38 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Gaye Kaya
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Impact Properties ◽  
Compression After Impact ◽  
Post Impact ◽  
The Impact ◽  
Hybrid Carbon

This study aims to compare the low-velocity impact and post-impact properties of intra-ply hybrid carbon/E-glass/polypropylene non-crimp thermoplastic composites with non-hybrid carbon/PP and E-glass/PP non-crimp thermoplastic composites. Impact test was performed at four energy levels as 15 J, 30 J, 45 J and 60 J. Post-impact properties of hybrid thermoplastic composites were tested by compression after impact method for each energy level to understand the impact damage tolerance of intra-ply hybrid carbon/E-glass/PP non-crimp thermoplastic composites. The effect of hybridization on energy absorption of composites was not significant, while C-scan results showed that the intra-ply hybrid non-crimp thermoplastic composites had smaller impact damage areas in comparison to the non-hybrid samples. Compression and compression after impact tests results confirmed that the intra-ply hybridization increased the toughness of the composite laminates. Also, the residual compression strength/modulus increased with hybridization which indicated to damage tolerance.

scholarly journals Discrepancy between two-dimensional and three-dimensional digital subtraction angiography for the planning of endovascular coiling of small cerebral aneurysms <5 mm

2020 ◽  
Vol 26 (6) ◽  
pp. 733-740
Author(s):  
Te-Chang Wu ◽  
Yu-Kun Tsui ◽  
Tai-Yuan Chen ◽  
Ching-Chung Ko ◽  
Chien-Jen Lin ◽  
...  
Keyword(s):  
Digital Subtraction Angiography ◽  
Three Dimensional ◽  
Cerebral Aneurysms ◽  
Endovascular Coiling ◽  
Parent Artery ◽  
Two Dimensional ◽  
Digital Subtraction ◽  
Rotational Angiography ◽  
Treatment Choices ◽  
The Impact

Background To investigate the discrepancy between two-dimensional digital subtraction angiography and three-dimensional rotational angiography for small (<5 mm) cerebral aneurysms and the impact on decision making among neuro-interventional experts as evaluated by online questionnaire. Materials and methods Eight small (<5 mm) ruptured aneurysms were visually identified in 16 image sets in either two-dimensional or three-dimensional format for placement in a questionnaire for 11 invited neuro-interventionalists. For each set, two questions were posed: Question 1: “Which of the following is the preferred treatment choice: simple coiling, balloon remodeling or stent assisted coiling?”; Question 2: “Is it achievable to secure the aneurysm with pure simple coiling?” The discrepancies of angio-architecture parameters and treatment choices between two-dimensional-digital subtraction angiography and three-dimensional rotational angiography were evaluated. Results In all eight cases, the neck images via three-dimensional rotational angiography were larger than two-dimensional-digital subtraction angiography with a mean difference of 0.95 mm. All eight cases analyzed with three-dimensional rotational angiography, but only one case with two-dimensional-digital subtraction angiography were classified as wide-neck aneurysms with dome-to-neck ratio < 1.5. The treatment choices based on the two-dimensional or three-dimensional information were different in 56 of 88 (63.6%) paired answers. Simple coiling was the preferred choice in 66 (75%) and 26 (29.6%) answers based on two-dimensional and three-dimensional information, respectively. Three types of angio-architecture with a narrow gap between the aneurysm sidewall and parent artery were proposed as an explanation for neck overestimation with three-dimensional rotational angiography. Conclusions Aneurysm neck overestimation with three-dimensional rotational angiography predisposed neuro-interventionalists to more complex treatment techniques. Additional two-dimensional information is crucial for endovascular treatment planning for small cerebral aneurysms.

Impact of Cavity on Sunroof Buffeting: A Two Dimensional CFD Study

2004 ◽  
Author(s):  
Chang-Fa An ◽  
Seyed Mehdi Alaie ◽  
Michael S. Scislowicz
Keyword(s):  
Fluid Dynamics ◽  
Wind Tunnel ◽  
Three Dimensional ◽  
Leading Edge ◽  
Two Dimensional ◽  
Deep Insight ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
The Impact ◽  
Insight Into

Driven by fluid dynamics principles, the concept for buffeting reduction, a cavity installed at the leading edge of the sunroof opening, is analyzed. The cavity provides a room to hold the vortex, shed from upstream, and prevents the vortex from escaping and from directly intruding into the cabin. The concept has been verified by means of a two dimensional simulation for a production SUV using the CFD software — FLUENT. The simulation results show that the impact of the cavity is crucial to reduce buffeting. It is shown that the buffeting level may be reduced by 3 dB by adding a cavity to the sunroof configuration. Therefore, the cavity could be considered as a means of buffeting reduction, in addition to the three currently-known concepts: wind deflector, sunroof glass comfort position and cabin venting. Thorough understanding of the buffeting mechanism helps explain why and how the cavity works to reduce buffeting. Investigation of the buffeting-related physics provides a deep insight into the flow nature and, therefore, a useful hint to geometry modification for buffeting reduction. The buffeting level may be further reduced by about 4 dB or more by cutting the corners of the sunroof opening into smooth ramps, guided by ideas coming from careful examining the physics of flow. More work including three dimensional simulation and wind tunnel experiment should follow in order to develop more confidence in the functionality of the cavity to hopefully promote this idea to the level that it can be utilized in a feasible way to address sunroof buffeting.

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