Assessment of contact-induced damage mechanisms in thick-walled composite cylinders

2020 ◽  
Vol 39 (17-18) ◽  
pp. 679-699
Author(s):  
Ruben AJ Weerts ◽  
Olivier Cousigné ◽  
Klaas Kunze ◽  
Marc GD Geers ◽  
Joris JC Remmers
Keyword(s):  
Damage Tolerance ◽  
Numerical Study ◽  
Failure Mechanisms ◽  
Pressure Vessels ◽  
Thick Wall ◽  
Thin Wall ◽  
Fiber Failure ◽  
Damage Mechanisms ◽  
Filament Wound ◽  
Composite Cylinders

In order to unravel the damage mechanisms occurring in composite-overwrapped pressure vessels (COPVs) subjected to crash conditions, a combined experimental-numerical study has been performed. For the purpose of generality and simplicity, quasi-static contacts on filament-wound cylinders are considered in this paper, as a precursor for geometrically complex impacts on COPVs. Rings with different wall thicknesses are tested to assess how failure mechanisms change when transitioning from thin-wall to thick-wall cylinders. The experimental results are used to identify, which mechanisms occur, and the numerical model is subsequently exploited to analyze the corresponding mechanisms. Based on the understanding of the mechanisms, a method to improve the damage tolerance of thick cylinders is presented. The rings are locally pre-delaminated during manufacturing to promote the growth of these pre-delaminations instead of the initiation of fiber failure.

scholarly journals Filament wound composite fatigue mechanisms investigated with full field DIC strain monitoring

2021 ◽  
Vol 11 (1) ◽  
pp. 401-413
Author(s):  
Eivind Hugaas ◽  
Andreas T. Echtermeyer
Keyword(s):  
Strain Field ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Image Correlation ◽  
Catastrophic Failure ◽  
Fiber Failure ◽  
Full Field ◽  
Matrix Cracks ◽  
Filament Wound ◽  
Over Time

Abstract Fatigue of filament wound materials was investigated using Digital Image Correlation DIC monitoring every 50th cycle of a high cycle fatigue test of a split disk ring sample. The ring was cut from a filament wound glass fiber reinforced polymer pressure vessel and had a hole. The strain field redistributed over time, lowering and moving strain concentrations. The redistributive behavior was most extensive in areas that later developed local fiber failure, which soon led to catastrophic failure. Microscopy was carried out on partially fatigued material. Damage evolved as matrix cracks and matrix splitting of groups of fibers and complete debonding of single fibers. This occurred at borders of voids and matrix cracks, easing progressive fiber failure. It was concluded that fatigue in filament wound composites has an extensive matrix damage phase before final failure. Fibers could locally withstand strains close to and above the static failure strain for considerable number of cycles if little local strain field redistribution was observed. The used method was able to detect changes in the strain fields that preceded catastrophic failure. It was concluded that DIC combined with the post processing methods presented may serve as a valuable tool for structural integrity monitoring of composite pressure vessels over time.

Composite Cylinders for Deep Sea Applications: An Overview

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Peter Davies ◽  
Dominique Choqueuse ◽  
Benoît Bigourdan ◽  
Pierre Chauchot
Keyword(s):  
Test Performance ◽  
Deep Sea ◽  
Impact Damage ◽  
Pressure Vessels ◽  
Thick Wall ◽  
Matrix Composites ◽  
Thermoplastic Matrix ◽  
Long Term Behavior ◽  
Composite Cylinders

In order to develop the knowledge base necessary to design deep sea pressure vessels, it is essential to understand the full chain from design and manufacturing through nondestructive testing (NDT) and characterization to long-term behavior under hydrostatic pressure. This paper describes results from European and national research programs focusing on the use of composites for underwater applications over the last 20 years. Initial tests on small glass/epoxy cylinders were followed by large demonstration projects on carbon/epoxy cylinders with implosion pressures of up to 600 bar, corresponding to 6000 m depth. Numerical modeling has enabled end closures design to be optimized for test performance. Thin and thick wall cylinders have been tested under quasi-static, and long-term loading. Both thermosetting and thermoplastic matrix composites have been tested to failure, and the influence of defects and impact damage on implosion pressure has been studied. These deep sea exploitation and exploration studies were performed for oceanographic, military, and offshore applications, and extensive data are available. The aim of this paper is to indicate existing results, particularly from European projects, in order to avoid costly repetition.

MICROSTRUCTURE ANALYSIS OF MOSO BAMBOO (Phyllostachys pubescens MAZEL) SURFACE AFTER UV RADIATION

2019 ◽  
Vol 27 (01) ◽  
pp. 1950090
Author(s):  
HAIXIA YU ◽  
XIN PAN ◽  
WEIMING YANG ◽  
WENFU ZHANG ◽  
XIAOWEI ZHUANG
Keyword(s):  
Uv Radiation ◽  
Cell Walls ◽  
Uv Light ◽  
Parenchyma Cell ◽  
Moso Bamboo ◽  
Thick Wall ◽  
Phyllostachys Pubescens ◽  
Thin Wall ◽  
Intercellular Spaces ◽  
Parenchyma Cell Walls

Bamboo material is widely used in outdoor applications. However, they are easily degraded when exposed to sunlight, their smooth surface will gradually turn to rough, and small cracks will appear and finally develop to large cracks. The paper presents a first-time investigation on the microstructure changes in the tangential section of Moso bamboo (Phyllostachys pubescens Mazel) radiated by artificial UV light. The results showed that the cracks mainly appeared at intercellular spaces of fibers where lignin content was high, the parenchyma cell walls and neighbor pits where the cell wall was very thin and more vulnerable than the other parts. In addition, the part of raised area and pit cavity tended to absorb more UV light radiation and showed more and larger cracks than the otherwhere. Cracks at the intercellular spaces of fibers were larger and bigger than those on the parenchyma cell walls. The cracks on the pits of the parenchyma cell walls normally appeared at one pit and then extended to the several surrounding pits. Bordered pits cavity showed more and larger cracks than the pits on the thin wall cells. The simple pits on the thick wall cells and the fiber cells were unaffected by UV radiation.

Development of Semi-Solid Die Casting Product Design and Die Design Technology for Aluminium Alloy Clamp

2016 ◽  
Vol 256 ◽  
pp. 334-339 ◽  
Author(s):  
Song Chen ◽  
Fan Zhang ◽  
You Feng He ◽  
Da Quan Li ◽  
Qiang Zhu
Keyword(s):  
Product Design ◽  
Die Casting ◽  
Casting Process ◽  
Die Design ◽  
Thick Wall ◽  
Thin Wall ◽  
Gating System ◽  
Cross Sectional ◽  
Die Casting Process ◽  
Semi Solid

Semi-solid slurry has significantly higher viscosity than liquid metal. This character of fluidity makes product design and die design, such as gating system, overflow and venting system, be different between these two die casting processes. In the present paper, taking a clamp product as an example, analyses the product optimization and die design by comparing the experimental and computational numerical simulation results. For the clamp, product structure is designed to be suitable for characters of SSM die casting process. The gating system is designed to be uniform variation of thickness, making the cross-sectional area uniformly reduce from the biscuit to the gate. This design ensures semi-solid metal slurry to fill die cavity from thick wall to thin wall. Gate position is designed at the thickest location, the gate shape of semi-solid die casting is set to be much bigger than traditional liquid casting. A good filling behaviour can be achieved by aforementioned all these design principles and it will be helpful to the intensification of pressure feeding after filling.

Strength Loss in Composite Cylinders Under Impact

1988 ◽  
Vol 110 (2) ◽  
pp. 180-184 ◽  
Author(s):  
A. P. Christoforou ◽  
S. R. Swanson
Keyword(s):  
Composite Structures ◽  
Composite Plates ◽  
Strength Loss ◽  
Pressure Vessels ◽  
Fourier Series Expansion ◽  
Lateral Impact ◽  
Low Velocity ◽  
Expansion Procedure ◽  
The Impact ◽  
Composite Cylinders

The problem of strength loss in composite structures due to impact appears to be important due to the sensitivity of advanced composites to these loadings. Although a number of studies have been carried out on impact of flat composite plates, relatively little work has been done on tubular geometries such as pressure vessels despite the usage in applications. We have addressed the problem of calculating strength loss due to low velocity, lateral impact of composite cylinders. In our model we use an existing Fourier Series expansion procedure to calculate ply stresses and strains, compare these values with allowables to predict fiber breakage during the impact, and finally use fracture mechanics to predict the strength loss due to the impact. Although the model is quite simplified, the general trends of experiments appear to be represented.

Tolerance of Composite Pipes to Local Impact Damage

1996 ◽  
Vol 210 (3) ◽  
pp. 181-192 ◽  
Author(s):  
S R Reid ◽  
C Peng ◽  
J N Ashton
Keyword(s):  
Damage Tolerance ◽  
Impact Damage ◽  
Local Loading ◽  
Experimental Programme ◽  
Filament Wound ◽  
Nose Shape ◽  
Local Impact ◽  
Chopped Strand Mat ◽  
Composite Pipes

The results of an extensive experimental programme on local loading of composite pipes are presented. Particular attention is directed to the influence of projectile nose shape on the damage tolerance of the pipes. Both filament wound pipes and lined chopped-strand mat pipes are considered.

Abstract 19170: Lesion Morphological Classification by Optical Coherence Tomography to Predict Therapeutic Efficacy After Balloon Pulmonary Angioplasty

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Taku Inohara ◽  
Takashi Kawakami ◽  
Masaharu Kataoka ◽  
Keiichi Fukuda
Keyword(s):  
Optical Coherence Tomography ◽  
Therapeutic Efficacy ◽  
Pressure Ratio ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Thick Wall ◽  
Thin Wall ◽  
Optical Coherence ◽  
Pressure Wire ◽  
Balloon Pulmonary Angioplasty ◽  
Lesion Morphology

Introduction: Conventionally, angiographic classification has been used for chronic thromboembolic pulmonary hypertension (CTEPH). However, a classification based on lesion morphology is needed in the era of balloon pulmonary angioplasty (BPA). We sought to propose a classification of CTEPH based on lesion morphology detected by optical coherence tomography (OCT) and to evaluate its association with physiological stenosis assessed with a pressure wire and therapeutic efficacy in BPA. Methods: We analyzed 43 lesions in 17 patients who were treated with BPA under OCT and pressure-wire guidance from November 2012 to March 2015. OCT findings were classified into the following 4 categories: 1) mono-hole, 2) septum, 3) multi-hole with thin wall, and 4) multi-hole with thick wall. Results: Angiographic findings did not match the specific morphologic classification based on OCT findings. At the pre-BPA assessment, the pressure ratio of the septum type was significantly higher than that of the mono-hole and multi-hole with thick wall types (p = 0.026 and 0.047, respectively). Under the OCT-based classification, more than 50% of the septum and multi-hole with thin wall types could accomplish >0.8 of the mean pressure ratio assessed by a pressure wire, and these proportions were significantly higher than those of the other 2 types: mono-hole and multi-hole with thick wall (p = 0.044). Based on angiographic classification, accomplishment of this criterion was not significantly different among angiographic types. Conclusions: OCT-based morphologic lesion classifications in CTEPH were useful to predict whether the lesion stenosis could improve to the acceptable level mediated by BPA.

A Comparative Study of Impact Effect of Composite Cylinders and Type IV Pressure Vessels

2021 ◽  
Vol 10 (1) ◽  
pp. 1-12
Author(s):  
Naseer H Farhood ◽  
Saravanan Karuppanan ◽  
Hamdan H Ya ◽  
Wisam A Abdul-Lateef
Keyword(s):  
Comparative Study ◽  
Pressure Vessels ◽  
Impact Effect ◽  
Type Iv ◽  
Composite Cylinders
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