scholarly journals High Strain Survivability of Piezoceramics by Optimal Bonding Adhesive Design

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2554 ◽  
Author(s):  
Hu Sun ◽  
Yishou Wang ◽  
Xinlin Qing ◽  
Zhanjun Wu
Keyword(s):  
Finite Element Analysis ◽  
Health Monitoring ◽  
Tensile Strain ◽  
High Strain ◽  
Aerospace Industry ◽  
Element Analysis ◽  
Strain Transfer ◽  
Impact Monitoring ◽  
Novel Approach ◽  
Host Structure

As one of the most common transducers used in structural health monitoring (SHM), piezoceramic sensors can play an important role in both damage detection and impact monitoring. However, the low tensile strain survivability of piezoceramics resulting from the material nature significantly limits their application on SHM in the aerospace industry. This paper proposes a novel approach to greatly improve the strain survivability of piezoceramics by optimal design of the adhesive used to bond them to the host structure. Theoretical model for determining the strain transfer coefficient through bonded adhesive from the host structure to piezoceramic is first established. Finite element analysis is then utilized to study the parameters of adhesive, including thickness and shear modulus. Experiments are finally conducted to validate the proposed method, and results show the piezoceramic sensors still work well when they are bonded on the host structures with tensile strain up to 4000 με by using the optimal adhesive.

A Finite Element Analysis on SAW Sensor for Torque Measuring

2014 ◽  
Vol 716-717 ◽  
pp. 1080-1083
Author(s):  
Li Jiu Wang ◽  
Yun Tao Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Thickness ◽  
Bonding Layer ◽  
Element Analysis ◽  
Strain Transfer ◽  
Saw Sensor ◽  
Sensing Applications ◽  
Host Structure ◽  
Material Mismatch

When detecting torque with surface acoustic wave (SAW) resonator sensors, the real strain of the host structure is not exactly consistent with the strain of SAW resonator due to material mismatch and the finite-thickness adhesive problem. A 3-layer (host structure, adhesive, and resonator layer) model is established. Finite-element Analysis (FEA) was used to investigate the strain transfer from the metal substrate to the SAW resonator (SAWR) through a bonding layer. The results show that the values of the strain transfer rate of FEA agree well with the experimental data. It can be concluded that FEA is of great value for SAW sensor design and sensing applications.

Design of the Full Scale Experiments for the Testing of the Tensile Strain Capacity of X52 Pipes With Girth Weld Flaws Under Internal Pressure and Tensile Displacement

2014 ◽  
Author(s):  
Celal Cakiroglu ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Millan Sen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Tensile Strain ◽  
Oil And Gas ◽  
Full Scale ◽  
Element Analysis ◽  
Simultaneous Application ◽  
Strain Capacity ◽  
Tensile Strain Capacity

Pipelines can be subjected to significant amounts of tensile forces due to geotechnical movements like slope instabilities and seismic activities as well as due to frost heave and thaw cycles in arctic regions. The tensile strain capacity εtcrit of pipelines is crucial in the prediction of rupture and loss of containment capability in these load cases. Currently the Oil and Gas Pipeline Systems code CSA Z662-11 0 contains equations for the prediction of εtcrit as a function of geometry and material properties of the pipeline. These equations resulted from extensive experimental and numerical studies carried out by Wang et al [2]–[6] using curved wide plate tests on pipes having grades X65 and higher. Verstraete et al 0 conducted curved wide plate tests at the University of Ghent which also resulted in tensile strain capacity prediction methods and girth weld flaw acceptability criteria. These criteria are included in the European Pipeline Research Group (EPRG) Tier 2 guidelines. Furthermore Verstrate et al 0 introduced a pressure correction factor of 0.5 in order to include the effect of internal pressure in the tensile strain capacity predictions in a conservative way. Further research by Wang et al with full scale pipes having an internal pressure factor of 0.72 also showed that εtcrit decreases in the presence of internal pressure [10]–[15]. In their work, Wang et al presented a clear methodology for the design of full scale experiments and numerical simulations to study the effect of internal pressure on the tensile strain capacity of pipes with girth weld flaws [10]–[15]. However, there has been limited testing to enable a precise understanding of the tensile strain capacity of pipes with grades less than X65 as a function of girth weld flaw sizes and the internal pressure. In this paper the experimental setup for the testing of grade X52 full scale specimens with 12″ diameter and ¼″ wall thickness is demonstrated. In the scope of this research 8 full scale specimens will be tested and the results will be used to formulate the tensile strain capacity of X52 pipes under internal pressure. The specimens are designed for the simultaneous application of displacement controlled tensile loading and the internal pressure. Finite element analysis is applied in the optimization process for the sizes of end plates and connection elements. Also the lengths of the full scale specimens are determined based on the results from finite element analysis. The appropriate lengths are chosen in such a way that between the location of the girth weld flaw and the end plates uniform strain zones could be obtained. The internal pressure in these experiments is ranging between pressure values causing 80% SMYS and 30% SMYS hoop stress. The end plates and connection elements of the specimens are designed in such a way that the tensile displacement load is applied with an eccentricity of 10% of the pipe diameter with the purpose of increasing the magnitude of tensile strains at the girth weld flaw location. The results of two full scale experiments of this research program are presented. The structural response from the experiments is compared to the finite element simulation. The remote strain values of the experiment are found to be higher than the εtcrit values predicted by the equations in 0.

scholarly journals Finite Element Analysis of Changes in Tensile Strain by Airsoft Gun Impact on Eye and Deformation Rate in Eyes of Various Axial Lengths

2020 ◽  
Vol Volume 14 ◽  
pp. 1445-1450
Author(s):  
Rie Takahashi ◽  
Kanno Okamura ◽  
Tomoko Tsukahara-Kawamura ◽  
Kazuhiro Harada ◽  
Yusuke Saeki ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Rate ◽  
Tensile Strain ◽  
Element Analysis

scholarly journals Bonded-bolted combination repair of a composite fuselage section

2021 ◽  
Author(s):  
Romeo Isaacs
Keyword(s):  
Finite Element Analysis ◽  
Endurance Limit ◽  
Aerospace Industry ◽  
Structural Deformation ◽  
Cad Model ◽  
Element Analysis ◽  
Composite Repair ◽  
Mechanical And Physical Properties ◽  
Materials Used ◽  
Ansys Workbench

Composite repair is an area of great importance, especially in the aerospace industry, due to the fact that an increasing number of modern aircrafts are utilizing these materials in larger quantities and in numerous areas in an effort to take advantage of their superior mechanical and physical properties. However, as result of their higher costs when compared to metals, replacing damaged structures could be a costly endeavour which is why composite repair is an excellent avenue to explore. This project aims to examine the suitability of a bonded-bolted combination repair for a damaged fuselage section through simulation by means of a finite element analysis on a CAD model. Catia V5 was used to create the model and the analysis was done in Ansys workbench. The repair section was compared with an undamaged section and after the application of pressure loads, the results indicated that there was a 10% increase in the stress and structural deformation of the repaired model when compared to the undamaged model. In addition, the stress in the materials used in the model was below that of their endurance limit.

A Novel Approach for Assessment of Pressurised Equipment for Slow Depressurisation During Fire

2018 ◽  
Author(s):  
Kaveh Ebrahimi ◽  
Saeid Rahimi Mofrad ◽  
Barry Millet ◽  
Kenneth Kirkpatrick ◽  
George Miller
Keyword(s):  
Finite Element Analysis ◽  
Cold Climate ◽  
Process Industry ◽  
Design Codes ◽  
Element Analysis ◽  
Economic Issues ◽  
Design Engineers ◽  
Novel Approach ◽  
Risk Of Rupture ◽  
Cold Case

Majority of modern design codes and regulations for pressurised equipment mandate that pressurised equipment are equipped with depressurising facilities so that in the event of an over-pressurising scenario or during emergency shut-downs the equipment can be safely depressurised. In the process industry, depressurisation calculations are usually done in accordance with the requirements of API 521 standard. For equipment with a wall thickness greater than 25mm, this standard recommends that depressurising facilities are designed to reduce the pressure of a vapour containing system exposed to external pool fire from the initial internal pressure to the final safe pressure within 15 minutes. There are cases where the depressurising time is even further shortened from 15 minutes by design engineers, e.g. for LPG applications or jet fire scenario. Once depressurisation facilities are sized for the fire-case, depressurising calculations are carried out in order to determine the minimum metal temperatures at coincident pressures reached in the equipment in a non-fire depressurising scenario (called cold-case). This will enable design engineers to analyse equipment for potential brittle fracture of equipment during cold-case depressurisation. Whilst the above mentioned methodology is usually adequate for majority of applications, there may be occasions that achieving API 521 recommended fire-case depressurisation time would require a large depressurising valve. This can potentially cause: • Significantly fast depressurising (and subsequent auto-refrigeration) in the cold-case leading to very low metal temperatures and the need for costly materials, particularly in cold climate environments; • Damage to equipment internals due to high depressurising rate; • Overloading the existing flare network in a brown field project. Increasing the depressurising time can alleviate the operational and/or economic issues arising from rapid depressurisations. However, slower-than-usual depressurisation increases the risk of rupture during fire-case, as equipment will be subject to heat for a longer period of time whilst still pressurised. This paper describes a methodology and identifies the necessary steps for assessment of pressurised equipment for slow depressurisations. The method is based on the provisions in the latest editions of API 521, API 579-1/ASME FFS-1 and Finite Element Analysis (FEA). A sample high pressure vessel is analysed in this paper for both cold and fire depressurisation.

scholarly journals Damage Detection in Glass/Epoxy Laminated Composite Plates Using Modal Curvature for Structural Health Monitoring Applications

2020 ◽  
Vol 4 (4) ◽  
pp. 185
Author(s):  
Mahendran Govindasamy ◽  
Gopalakrishnan Kamalakannan ◽  
Chandrasekaran Kesavan ◽  
Ganesh Kumar Meenashisundaram
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Damage Detection ◽  
Health Monitoring ◽  
Strain Energy ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Element Analysis ◽  
Modal Curvature

This paper deals with detection of macro-level crack type damage in rectangular E-Glass fiber/Epoxy resin (LY556) laminated composite plates using modal analysis. Composite plate-like structures are widely found in aerospace and automotive structural applications which are susceptible to damages. The formation of cracks in a structure that undergoes vibration may lead to catastrophic events such as structural failure, thus detection of such occurrences is considered necessary. In this research, a novel technique called as node-releasing technique in Finite Element Analysis (FEA), which was not attempted by the earlier researchers, is used to model the perpendicular cracks (the type of damage mostly considered in all the pioneering research works) and also slant cracks (a new type of damage considered in the present work) of various depths and lengths for Unidirectional Laminate (UDL) ([0]S and [45]S) composite layered configurations using commercial FE code Ansys, thus simulating the actual damage scenario. Another novelty of the present work is that the crack is modeled with partial depth along the thickness of the plate, instead of the through the thickness crack which has been of major focus in the literature so far, in order to include the possibility of existence of the crack up to certain layers in the laminated composite structures. The experimental modal analysis is carried out to validate the numerical model. Using central difference approximation method, the modal curvature is determined from the displacement mode shapes which are obtained via finite element analysis. The damage indicators investigated in this paper are Normalized Curvature Damage Factor (NCDF) and modal strain energy-based methods such as Strain Energy Difference (SED) and Damage Index (DI). It is concluded that, all the three damage detection algorithms detect the transverse crack clearly. In addition, the damage indicator NCDF seems to be more effective than the other two, particularly when the detection is for damage inclined to the longitudinal axis of the plate. The proposed method will provide the base data for implementing online structural health monitoring of structures using technologies such as Machine Learning, Artificial Intelligence, etc.

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