Experimental Verification of Effect of Adhesive Layer Thickness Used for Strain Gauge Mounting

2015 ◽  
Vol 1119 ◽  
pp. 789-793
Author(s):  
K. Subrahmanya ◽  
K. Vadivuchezhian ◽  
N. Chockappan
Keyword(s):  
Layer Thickness ◽  
Strain Gauge ◽  
Strain Measurement ◽  
Adhesive Layer ◽  
Thickness Effect ◽  
Strain Gauges ◽  
Analytical Results ◽  
Adhesive Thickness ◽  
Basic Strength ◽  
Adhesive Materials

Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. Effect of adhesive layer thickness has been addressed in this paper. Well characterized tensile experiments have been conducted using Al 6061-T6 specimens attached with strain gauges at mid length of the specimen and strain gauges are attached with different materials namely epoxy and polyurethane to understand the effect of adhesive layer thickness in strain measurement. The strain at a location has been noted for one particular adhesive layer thickness value (0.13 mm) and similar experiments have been carried out with different adhesive thickness values (0.16 mm, 0.18 mm and 0.26 mm). The results obtained from experiments have been compared with analytical results from Basic Strength of Materials approach. Good agreement is seen between the experimental and analytical results. It has been observed that the thickness of the adhesive layer plays significant role for getting accurate strain.

Finite Element Modeling of Effect of Adhesive Layer and Carrier Thickness Used for Strain Gauge Mounting

2015 ◽  
Vol 1119 ◽  
pp. 828-832
Author(s):  
K. Vadivuchezhian ◽  
K. Subrahmanya ◽  
N. Chockappan
Keyword(s):  
Finite Element ◽  
Strain Gauge ◽  
Adhesive Layer ◽  
Element Model ◽  
Strain Gauges ◽  
Single Element ◽  
Metal Foil ◽  
Engineering Structures ◽  
Element Analysis ◽  
Typical Strain

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.

Measurement of Strain Using Strain Gauge and Piezoelectric Sensors

2020 ◽  
pp. 91-101
Author(s):  
Abhishek Kamal ◽  
Vinayak Kulkarni ◽  
Niranjan Sahoo
Keyword(s):  
Strain Gauge ◽  
Crucial Role ◽  
Strain Measurement ◽  
Strain Sensors ◽  
Piezoelectric Sensors ◽  
Strain Gauges ◽  
Research Fields ◽  
Different Types ◽  
Optical Strain ◽  
Semiconductor Strain

Today, measurement of strain plays a crucial role in different areas of research such as manufacturing, aerospace, automotive industry, agriculture, and medical. Many researchers have used different types of strain transducers to measure strain in their relevant research fields. Strain can be measured using mainly two methods (i.e., electrical strain sensors and optical strain sensors). Electrical strain sensors consist basically of strain gauges, piezo film, etc. In electrical strain sensors, the strain gauge is one of the oldest and reliable strain sensors which are available in different types (i.e., wire strain gauge, foil strain gauge, and semiconductor strain gauge). Piezofilm is also playing an important role in the field of strain measurement due to easy availability and less cost.

Use of the Fokker Bond Tester on Joints with Varying Adhesive Thickness

1987 ◽  
Vol 201 (1) ◽  
pp. 41-49 ◽  
Author(s):  
C C H Guyott ◽  
P Cawley ◽  
R D Adams
Keyword(s):  
Layer Thickness ◽  
Natural Frequencies ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Cohesive Strength ◽  
Piezoelectric Crystal ◽  
Adhesive Properties ◽  
Resonant Frequencies ◽  
Wide Range ◽  
Adhesive Thickness

The operation of the Fokker bond tester has been investigated. The instrument monitors one of the natural frequencies of the system comprising a piezoelectric crystal coupled to the joint under test. The resonant frequencies of two different sizes of transducer coupled to both plain plates and adhesive joints have been investigated both theoretically and experimentally, the measured values being in line with the predictions. It has been concluded that the method is satisfactory for the location of disbonds in a multi-layer construction but that it cannot distinguish between adhesive modulus and adhesive layer thickness. Both of these parameters affect the adhesive stiffness and hence the measured resonant frequencies. However, they have different effects on the cohesive strength of the adhesive so unless independent measurements of, for example, thickness are made, erroneous strength predictions may be obtained. Also, the measured frequencies are independent of adhesive stiffness over a wide range of typical stiffnesses, so changes in adhesive properties will not be measured in these cases.

scholarly journals Characterization of an Experimental Two-Step Self-Etch Adhesive’s Bonding Performance and Resin-Dentin Interfacial Properties

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1009
Author(s):  
Abu Faem Mohammad Almas Chowdhury ◽  
Arefin Alam ◽  
Monica Yamauti ◽  
Pedro Álvarez Lloret ◽  
Pipop Saikaew ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Water Storage ◽  
Adhesive Layer ◽  
Third Molars ◽  
Microtensile Bond Strength ◽  
Universal Adhesive ◽  
Bonding Performance ◽  
Adhesive Thickness ◽  
Self Etch

This study evaluated an experimental two-step self-etch adhesive (BZF-29, BZF) by comparing it with a reference two-step self-etch adhesive (Clearfil Megabond 2, MB) and a universal adhesive (G-Premio Bond, GP) for microtensile bond strength (μTBS) and resin-dentin interfacial characteristics. Twenty-four human third molars were used for the μTBS test. Bonded peripheral dentin slices were separated to observe the resin-dentin interface and measure the adhesive layer thickness with SEM. μTBS data of the central beams were obtained after 24 h and 6 months of water storage. Fracture modes were determined using a stereomicroscope and SEM. Nine additional third molars were used to determine the elastic modulus (E) employing an ultra microhardness tester. Water storage did not affect μTBS of the tested adhesives (p > 0.05). μTBS of BZF and MB were similar but significantly higher than GP (p < 0.05). BZF achieved the highest adhesive layer thickness, while GP the lowest. E of BZF and MB were comparable but significantly lower than GP (p < 0.05). Except for GP, the predominant fracture mode was nonadhesive. The superior bonding performance of BZF and MB could be attributed to their better mechanical property and increased adhesive thickness imparting better stress relief at the interface.

scholarly journals Comparison of Resistive and Optical Strain Measurement for Early Fracture Detection

2020 ◽  
Vol 6 (3) ◽  
pp. 196-199
Author(s):  
Alina Carabello ◽  
Constanze Neupetsch ◽  
Michael Werner ◽  
Christian Rotsch ◽  
Welf-Guntram Drossel ◽  
...  
Keyword(s):  
Surgical Training ◽  
Error Detection ◽  
Strain Measurement ◽  
Testing Machine ◽  
Image Correlation ◽  
Strain Gauges ◽  
Measurement Technology ◽  
Bone Surface ◽  
Fracture Detection ◽  
Local Strains

AbstractTo increase learning success in surgical training, physical simulators are supplemented by measurement technology to generate and record objective feedback and error detection. An opportunity to detect fractures following hip stem implantation early can be measurement of occurring strains on bone surface. These strains can be determined while using strain gauges, digital image correlation (DIC) or photoelasticity. In this research strain gauges and DIC were compared regarding their suitability as strain measurement tools for use in physical simulators. Therefore a testing method was described to replicate the implantation of a hip stem. Testing devices modelled on a realistic prosthesis were pressed into prepared porcine femora in a two-step procedure with a material testing machine. The local strains occurring on bone surface were determined using an optical measurement system for DIC and strain gauges. The initial fractures in the tested femora are located medial-anterior in most cases (73,6%). With increasing indentation depth of the test device, the strains on bone surface increase. Comparing the local strains determined by DIC and strain gauges consistencies in curves are noticeable. Maximal determined strains before fracturing amount to 0,69% with strain gauges and 0,75% with DIC. In the range of the fracture gap, strain gradients are determined by using DIC. However the detected surfaces are of low quality caused by gaps and motion artefacts. The results show strains on bone surfaces for early fracture detection are measurable with strain gauges and DIC. DIC is assessed as less suitable compared to strain gauges. Furthermore strain gauges have greater level of integration and economic efficiency, so they are preferred the use in surgical training simulators.

Optical strain measurements on fast moving fiber reinforced polymer rotors using diffraction gratings

2019 ◽  
Vol 86 (3) ◽  
pp. 175-183
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Robert Kuschmierz ◽  
...  
Keyword(s):  
Rigid Body ◽  
Strain Measurement ◽  
Composite Structures ◽  
Dynamical Behavior ◽  
Image Correlation ◽  
Fiber Reinforced Polymers ◽  
Strain Gauges ◽  
Objective Lens ◽  
Fiber Reinforced ◽  
Body Movements

AbstractIn-situ measurements of the deformation and of the structural dynamical behavior of moving composite structures, such as rotors made of glass fiber reinforced polymers (GFRP), are necessary in order to validate newly developed simulation models. Local methods like strain gauges and fiber Bragg gratings lack spatial resolution, while contactless optical methods like image correlation or speckle interferometry suffer from noise effects in the presence of fast rigid body movements. A novel compact sensor – based on the diffraction grating method – is introduced for spatially and temporally resolved strain measurement. The use of a line camera allows the measurement of vibrations up to several tens of kHz. With a scanning movement, strain fields at submillimeter resolution can be recorded. The use of two diffraction orders and an objective lens reduces cross sensitivities to rigid body movements on the strain measurement by two to three orders of magnitude. A validation on a GFRP probe was conducted in a quasi-static tensile test with an optical extensometer up to 14500 µϵ. Furthermore, a strain measurement on a moving rotor at surface speeds up to 75 m/s was performed and the results were compared with those of strain gauges as a gold standard. The statistical standard deviation was around 10 µϵ and independent of the rotational speed.

Development of a Quick and Easy-to-Install Strain Measurement Tool for Both Bending and Torsional Piping Stress Assessment

2016 ◽  
Author(s):  
Tsunemichi Takahama ◽  
Kazuma Nishimura ◽  
Seiichiro Ninomiya ◽  
Yoshihiro Matsumoto ◽  
Yutaka Harada
Keyword(s):  
Strain Gauge ◽  
Strain Measurement ◽  
Adhesive Bonding ◽  
Working Time ◽  
Measurement Tool ◽  
Stress Assessment ◽  
The Moment ◽  
Time Required ◽  
Longitudinal Strains

To assess the stresses on small-bore piping, we have developed a new tool that can be easily installed on a piping surface without adhesive bonding and that measures strains on piping quickly and accurately. This tool, which we call a “strain gauge holder,” is patented in Japan. As the tool can contain four strain gauge rosettes, with each rosette comprising three elements, the longitudinal strains and sheer strains can be measured synchronously at any four points precisely 90 degrees apart, with one point in each quadrant. By mockup testing, we confirmed that the measured bending and torsional strains by the holder were almost equivalent to the measured strains by the bonded gauges with adhesive, and that the holder made it possible to synchronously measure all of the strains resulting from the moment of force acting in three axes on the piping by measuring the bending and torsional strains in each quadrant. The strain gauge holder is expected to significantly reduce the pre- and post-working time required for strain measurement and stress assessment of piping in real plants.

Influence of Adhesive Layer on Actuation of Lamb Wave Signals

2012 ◽  
Vol 525-526 ◽  
pp. 617-620 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
Qu Liu ◽  
M.H. Aliabadi
Keyword(s):  
Lamb Wave ◽  
Adhesive Layer ◽  
Composite Plates ◽  
Wave Generation ◽  
Actuation Frequency ◽  
Adhesive Thickness

In this work, Lamb wave generation and propagation have been modelled in composite plates. Actuation and acquisition of signals when the PZT transducers are tied to the structure or bonded with an adhesive layer are investigated. The effect of adhesive thickness and actuation frequency of Lamb wave have been examined.

Optimum Strain Gauge Application to Bladed Assemblies

2002 ◽  
Author(s):  
J. Szwedowicz ◽  
S. M. Senn ◽  
R. S. Abhari
Keyword(s):  
Strain Gauge ◽  
Element Model ◽  
Strain Gauges ◽  
Structural Components ◽  
Algorithm Optimization ◽  
Rotating Blades ◽  
Novel Approach ◽  
Present Technique ◽  
Optimization Function ◽  
Rotating Impeller

Optimum placements of the strain gauges assure reliable vibration measurements of structural components such as rotating blades. Within the framework of cyclic vibration theory, a novel approach has been developed for computation of the optimum gauge positions on tuned bladed discs regarding the determined sensitivity, orthogonality, gradient and distance criteria. The utilized genetic algorithm optimization tool allows for an effective numerical search of suitable solutions of the defined optimization function. A rotating impeller disc represented by a cyclic finite element model demonstrates the application of this method. The present technique can be easily applied to other structural components requiring optimal strain gauge instrumentation.

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