Measurement of Adhesive Bonding Strength With an EMAT in the Resonant Mode

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Tianhao Liu ◽  
Haiqiang Zhou ◽  
Cuixiang Pei ◽  
Zhenmao Chen
Keyword(s):  
Attenuation Coefficient ◽  
Bonding Strength ◽  
Adhesive Bonding ◽  
Signal To Noise Ratio ◽  
Plate Thickness ◽  
Acoustic Resonance ◽  
Resonant Mode ◽  
Imperfect Interface ◽  
Electromagnetic Acoustic Transducer ◽  
Strength Evaluation

Abstract The electromagnetic acoustic resonance (EMAR) method with shear wave is sensitive to boundary conditions and plate thickness. In this paper, a new noncontact ultrasonic testing method based on the electromagnetic acoustic transducer (EMAT) in the resonant mode is proposed for the bonding strength evaluation in metal-based adhesive structures. Different from the conventional pulse-echo method using short-burst excitation for bonding inspection, the attenuation coefficient feature of the resonant ultrasonic signal with long-burst excitation is applied to increase the signal-to-noise ratio (SNR) and detecting sensitivity of the EMAT for adhesive bonding strength evaluation. A theoretical model for adhesive bonding testing with EMAT signals in the resonant mode is established. To extract the signal feature representing the reflection coefficient, the time-domain signal was processed by Hilbert transformation and exponential curve fitting. Through the simulation on the received signal, the correlation between the attenuation coefficient of the exponent fitted curve and the strength on the adhesive imperfect interface were confirmed. Finally, the proposed correlation is verified by an experiment on stainless steel plates bonded with polymethyl methacrylate plates by epoxy adhesion via a permanent magnetic EMAT.

Optimal design of shear vertical wave electromagnetic acoustic transducers in resonant mode

2020 ◽  
Vol 64 (1-4) ◽  
pp. 639-647
Author(s):  
Zhichao Cai ◽  
Zhenyong Zhao ◽  
Lan Chen ◽  
Guiyun Tian
Keyword(s):  
Permanent Magnets ◽  
Signal To Noise Ratio ◽  
Acoustic Resonance ◽  
Element Model ◽  
Response Characteristic ◽  
Resonant Mode ◽  
Thickness Measurement ◽  
Frequency Interval ◽  
Resonant Amplitude ◽  
The Common

In this paper, a new electromagnetic acoustic resonance (EMAR) transducer is proposed for precise thickness measurement in specimen. The new EMAR is composed of a mirror symmetric coil (MSC) and a pair of Nd-Fe-B permanent magnets with the different polarity for enhancing the generation and detection of resonant signals. Firstly, a finite element model was established to simulate the distributions of Lorentz force produced by new EMAR and the resonant process of shear waves. Furthermore, the relationship between the frequency response characteristic of the new EMAR and the common EMAR were explored. Finally, to verify the performance of the EMAR, several experiments were performed. Compared with the common EMAR transducer, the resonant amplitude of the new EMAR transducer was increased by 121.74% and the signal-to-noise ratio was increased by 28.35%, and the resonance frequency interval of the new EMAR was twice that of the common mode in the frequency domain simulation experiment, this advantage effectively reduced the error rate of measurement. The results show that the new EMAR transducer with mirror coil structure has higher accuracy in thickness detection of specimens.

Vacuum Adhesive Bonding and Stress Isolation for MEMS Resonant Pressure Sensor Package

2011 ◽  
Vol 694 ◽  
pp. 896-900 ◽  
Author(s):  
Yu Xin Li ◽  
De Yong Chen ◽  
Jun Bo Wang
Keyword(s):  
Pressure Sensor ◽  
Bonding Strength ◽  
Adhesive Bonding ◽  
Thermal Stresses ◽  
Time Pressure ◽  
Bonding Temperature ◽  
Bonding Process ◽  
Temperature Drift ◽  
Stress Isolation ◽  
Sensor Package

This paper presents a method of low temperature adhesive bonding and stress isolation for MEMS resonant pressure sensor hermetic packaging using non-photosensitive benzo-cyclo-butene (BCB) from Dow Co. According to the bonding process, pre-bake time, pumping time, pressure placed on the sensor and the thickness of crosslink layer are the most important factors. Stress isolation is designed to minimize thermal stresses to the resonant pressure sensor package. Experimental results show that this bonding process is a viable for MEMS resonant pressure sensor with the bonding temperature below 250°C, measured bonding strength more than 30MPa, the temperature drift less than 0.05%/°C in the range of -40°C to 70°C(10% of that without stress isolation), and the bonding strength maintains well after thermal treatments, handling, bench testing and implantations.

scholarly journals A FULL-SCALE STUDY OF THE STRENGTH OF MASSIVE WOOD GLUING WITH MODERN ADHESIVES WHEN OPERATING IN VARIOUS CONDITIONS

2020 ◽  
Vol 10 (1) ◽  
pp. 105-115
Author(s):  
Larisa Ponomarenko ◽  
Ekaterina Kantieva ◽  
Maksim Posluhaev ◽  
Aleksandr Chernyshev
Keyword(s):  
Bonding Strength ◽  
Polyvinyl Acetate ◽  
Adhesive Bonding ◽  
Adhesive Layer ◽  
Correct Choice ◽  
Operating Conditions ◽  
Furniture Manufacturing ◽  
Wooden House ◽  
House Building ◽  
Adhesive Materials

Abstract Glues are widely used to connect various materials, especially since in some cases other options for combining materials are not suitable. The paper deals with the bonding of solid hardwood with modern adhesive materials. Currently, a large group of adhesives of various brands from Russian and foreign manufacturers is presented on the market. In the woodworking industry, adhesives are used in the carpentry and furniture, manufacturing, in wooden house-building, in the production of finishing materials, etc., which are operated outside and inside the premises in constant and variable humidity conditions. Therefore, the correct choice of adhesives plays an important role both for the manufacturer and subsequently for the consumer of the resulting product. In this work, we have studied the dependence of the tensile strength when chipping along the adhesive layer on the type of glue, wood species, and operating conditions. We have selected the following adhesives based on polychloroprene, polyvinyl acetate and rubber. The greatest strength of the adhesive bonding when gluing solid hardwood is given by polyvinyl acetate adhesives. When using the product in conditions of changing temperature and humidity, the bonding strength decreases, in some cases significantly. In fairness, it should be noted that not only the type of glue, but also the type of wood affects the bonding strength

Damascene-Patterned Metal-Adhesive (Cu-BCB) Redistribution Layers

2006 ◽  
Vol 970 ◽  
Author(s):  
Ronald J. Gutmann ◽  
J. Jay McMahon ◽  
Jian-Qiang Lu
Keyword(s):  
Bonding Strength ◽  
Adhesive Bonding ◽  
Process Integration ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Wafer Level ◽  
Technology Platform ◽  
Metal Bonding ◽  
Wafer Level Packaging ◽  
Metal Metal

ABSTRACTA monolithic, wafer-level three-dimensional (3D) technology platform is described that is compatible with next-generation wafer level packaging (WLP) processes. The platform combines the advantages of both (1) high bonding strength and adaptability to IC wafer topography variations with spin-on dielectric adhesive bonding and (2) process integration and via-area advantages of metal-metal bonding. A copper-benzocyclobutene (Cu-BCB) process is described that incorporates single-level damascene-patterned Cu vias with partially-cured BCB as the bonding adhesive layer. A demonstration vehicle consisting of a two-wafer stack of 2-4 μm diameter vias has shown the bondability of both Cu-to-Cu and BCB-to-BCB. Planarization conditions to achieve BCB-BCB bonding with low-resistance Cu-Cu contacts have been examined, with wafer-scale planarization requirements compared to other 3D platforms. Concerns about stress induced at the tantalum (Ta) liner-to-BCB interface resulting in partial delamination are discussed. While across-wafer uniformity has not been demonstrated, the viability of this WLP-compatible 3D platform has been shown.

scholarly journals Hierarchical Surface Texturing of Hydroxyapatite Ceramics: Influence on the Adhesive Bonding Strength of Polymeric Polycaprolactone

2020 ◽  
Vol 11 (4) ◽  
pp. 73
Author(s):  
Jonas Biggemann ◽  
Philipp Müller ◽  
David Köllner ◽  
Swantje Simon ◽  
Patrizia Hoffmann ◽  
...  
Keyword(s):  
Bonding Strength ◽  
Adhesive Bonding ◽  
Surface Texturing ◽  
Independent Effect ◽  
Nanometer Scale ◽  
Submillimeter Range ◽  
Covalent Bonds ◽  
Hydroxyapatite Ceramics ◽  
Materials Used ◽  
The Individual

The tailored manipulation of ceramic surfaces gained recent interest to optimize the performance and lifetime of composite materials used as implants. In this work, a hierarchical surface texturing of hydroxyapatite (HAp) ceramics was developed to improve the poor adhesive bonding strength in hydroxyapatite and polycaprolactone (HAp/PCL) composites. Four different types of periodic surface morphologies (grooves, cylindric pits, linear waves and Gaussian hills) were realized by a ceramic micro-transfer molding technique in the submillimeter range. A subsequent surface roughening and functionalization on a micron to nanometer scale was obtained by two different etchings with hydrochloric and tartaric acid. An ensuing silane coupling with 3-aminopropyltriethoxysilane (APTES) enhanced the chemical adhesion between the HAp surface and PCL on the nanometer scale by the formation of dipole–dipole interactions and covalent bonds. The adhesive bonding strengths of the individual and combined surface texturings were investigated by performing single-lap compressive shear tests. All individual texturing types (macro, micro and nano) showed significantly improved HAp/PCL interface strengths compared to the non-textured HAp reference, based on an enhanced mechanical, physical and chemical adhesion. The independent effect mechanisms allow the deliberately hierarchical combination of all texturing types without negative influences. The hierarchical surface-textured HAp showed a 6.5 times higher adhesive bonding strength (7.7 ± 1.5 MPa) than the non-textured reference, proving that surface texturing is an attractive method to optimize the component adhesion in composites for potential medical implants.

Combustion Instabilities in Industrial Gas Turbines—Measurements on Operating Plant and Thermoacoustic Modeling

2000 ◽  
Vol 122 (3) ◽  
pp. 420-428 ◽  
Author(s):  
David E. Hobson ◽  
John E. Fackrell ◽  
Gary Hewitt
Keyword(s):  
Time Delay ◽  
Gas Turbines ◽  
Acoustic Resonance ◽  
Resonant Mode ◽  
Combustion Stability ◽  
Combustion Instabilities ◽  
Strong Function ◽  
Fuel Supply ◽  
Industrial Gas Turbines ◽  
Stability Limits

Measurements of vibration and combustion chamber dynamic pressures have been taken on a number of 150 MW industrial gas turbines operating on pre-mixed natural gas, both during long periods of base-load operation and during short duration load-swings. The data has been analyzed in terms of the frequency and bandwidth of the principle peak in the vibration and pressure spectra as a function of load and other operating parameters. It is observed that bandwidth, which is a measure of the damping of the resonant mode of the combustion chamber’s acoustic resonance, decreases towards zero as the machines approach their combustion stability limits. A theoretical model of the thermoacoustic behavior of the combustion system has been developed to see to what extent the observed behavior on the operational machines can be explained in terms of an acoustic model of the ductwork and a flame characterized simply by a time-delay. This time delay is obtained from the frequency response function of the flame in response to unsteady perturbations in inlet velocity and is calculated using computational fluid dynamics. The model has also been used to illustrate the importance of fuel supply system design in controlling combustion stability. It is shown that stability can be a strong function of the acoustic impedance of the fuel supply and that this can lead to enhanced or reduced stability depending on the flame characteristics. [S0742-4795(00)01403-4]

Structural Nanocomposite Bonding Reinforced by Graphite Nanofibers with Surface Treatments

2004 ◽  
Vol 843 ◽  
Author(s):  
L. Roy Xu ◽  
Charles M. Lukehart ◽  
Lang Li ◽  
Sreeparna Sengupta ◽  
Ping Wang
Keyword(s):  
Bonding Strength ◽  
Adhesive Bonding ◽  
Covalent Binding ◽  
Strength Increase ◽  
Thermal Curing ◽  
Graphite Nanofibers ◽  
Shear Joint ◽  
Metal Metal ◽  
Graphitic Carbon Nanofibers ◽  
Linker Molecules

ABSTRACTGraphitic carbon nanofibers were used to reinforce epoxy resin to form nanocomposite adhesive bonding. GCNFs having a herringbone atomic structure are surface-derivatized with bifunctional hexanediamine linker molecules capable of covalent binding to an epoxy matrix during thermal curing and are cut to smaller dimension using ultrasonication. Good dispersion and polymer wetting of the GCNF component is evident on the nanoscale. Tensile and shear joint strength measurements were conducted for metal-metal and polymer-polymer joints using pure epoxy and nanocomposite bonding. Very little bonding strength increase, or some bonding strength decrease, was measured.

Combustion Instabilities in Industrial Gas Turbines — Measurements on Operating Plant and Thermoacoustic Modelling

1999 ◽  
Author(s):  
David E. Hobson ◽  
John E. Fackrell ◽  
G. Hewitt
Keyword(s):  
Time Delay ◽  
Gas Turbines ◽  
Acoustic Resonance ◽  
Resonant Mode ◽  
Combustion Stability ◽  
Strong Function ◽  
Fuel Supply ◽  
Industrial Gas Turbines ◽  
Observed Behaviour ◽  
Stability Limits

Measurements of vibration and combustion chamber dynamic pressures have been taken on a number of 150MW industrial gas turbines operating on pre-mixed natural gas, both during long periods of base-load operation and during short duration load-swings. The data has been analysed in terms of the frequency and bandwidth of the principle peak in the vibration and pressure spectra as a function of load and other operating parameters. It is observed that bandwidth, which is a measure of the damping of the resonant mode of the combustion chamber’s acoustic resonance, decreases towards zero as the machines approach their combustion stability limits. A theoretical model of the thermoacoustic behaviour of the combustion system has been developed to see to what extent the observed behaviour on the operational machines can be explained in terms of an acoustic model of the ductwork and a flame characterised simply by a time-delay. This time delay is obtained from the frequency response function of the flame in response to unsteady perturbations in inlet velocity and is calculated using computational fluid dynamics. The model has also been used to illustrate the importance of fuel supply system design in controlling combustion stability. It is shown that stability can be a strong function of the acoustic impedance of the fuel supply and that this can lead to enhanced or reduced stability depending on the flame characteristics.

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