”Automatized” Peel Testing: Calculated Stresses and Deflections in the Film

1989 ◽  
Vol 154 ◽  
Author(s):  
Ephraim Suhir
Keyword(s):  
Peel Test ◽  
Air Pressure ◽  
Film Material ◽  
Large Deflections ◽  
Test Vehicle ◽  
Reliability Factor ◽  
Peel Testing ◽  
Film Adhesion ◽  
Peel Tests ◽  
The Given

AbstractFilm adhesion, which is an important reliability factor in many microelectronic structures, is usually evaluated by peel testing. The loading and the peel angle in peel tests can be controlled best if these tests are “automatized”, which could be done, for instance, by applying air pressure to a film through an opening in the substrate. We consider a rectangular opening and determine, how this pressure is related to the peel (membrane) loading and peel angle for the given film material and thickness. Our study is based on von-Kármán's equations for large deflections of plates. The obtained results provide mechanical fundamentals for a rational physical design of a peel test vehicle.

“Automatized” Peel Testing: Calculated Stresses and Deflections in the Film

1989 ◽  
Vol 153 ◽  
Author(s):  
Ephraim Suhir
Keyword(s):  
Peel Test ◽  
Air Pressure ◽  
Film Material ◽  
Large Deflections ◽  
Test Vehicle ◽  
Reliability Factor ◽  
Peel Testing ◽  
Film Adhesion ◽  
Peel Tests ◽  
The Given

AbstractFilm adhesion, which is an important reliability factor in many microelectronic structures, is usually evaluated by peel testing. The loading and the peel angle in peel tests can be controlled best if these tests are “automatized”, which could be done, for instance, by applying air pressure to a film through an opening in the substrate. We consider a rectangular opening and determine, how this pressure is related to the peel (membrane) loading and peel angle for the given film material and thickness. Our study is based on von-Kármán's equations for large deflections of plates. The obtained results provide mechanical fundamentals for a rational physical design of a peel test vehicle.

Mechanics of the Peel Test for Thin Film Adhesion

1988 ◽  
Vol 119 ◽  
Author(s):  
K-S. Kim
Keyword(s):  
Thin Film ◽  
Integral Equation ◽  
Peel Test ◽  
Peel Strength ◽  
Metallic Films ◽  
Interface Toughness ◽  
Film Adhesion ◽  
Expenditure Rate ◽  
Thin Film Adhesion ◽  
Peel Tests

AbstractThe mechanics aspects of the peel test are analyzed. In this analysis, the limitation and applicability of the peel test for thin film adhesion have been investigated. Firstly, the effect of plasticity in the peel test of thin metallic films is analyzed. The analysis has given a closed form solution for the partitioning of peel strength between the energy expenditure rate for the decohesion process and the internal work expenditure rate caused by plastic deformation (bending) of the film. The results predicted the variation of peel strength as a function of the film thickness, the film yield stress and the compliance of the substrate. This analysis shows that the peel strength is very sensitive to the thickness of the film and the yield stress of the film. As observed in the experiment, the peel strength has a peak value at a certain thickness of the film. This is explained for both L and T peel tests. Unlike the L peel test, the peak phenomenon in the T peel test (of metallic films) is due to the hardening of the adhered film. Secondly, the effect of plasticity and viscoelasticity in the peel test of thin polymer films is analyzed. Unlike the peel test of metallic films, tension and shear effect of the film deformation is very important in the analysis of the polymer peel test. An integral equation is formulated for the viscoelastic models of the adhered film. The solution of the integral equation reveals the important parameters in polymer peeling and their contribution to the peel force as well as to the viscoelastic dissipation. In addition, the meaning of the interface toughness is reexamined and the interface toughness is evaluated by the peel test. Based on these analyses, a Universal Peel Diagram has been constructed, which accounts for the hardening behavior of the film. On this diagram, objective interfacial decohesion toughness can be readily obtained using very simple peel tests. The analysis includes not only the 900° peel test but also the general angle peel test. Comparison between the theory and experiment has been made with the experimental data provided by J. Kim of IBM. The comparison shows good agreement.

Characterisation of the opening behavior of multilayer films with cohesive failure mechanism by in situ peel tests in the ESEM

2021 ◽  
pp. 875608792110255
Author(s):  
M Heuser ◽  
A Zankel ◽  
C Mayrhofer ◽  
K Reincke ◽  
B Langer ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
Peel Test ◽  
Multilayer Films ◽  
Cohesive Failure ◽  
Packaging Process ◽  
Flexible Packaging ◽  
Alignment Angle ◽  
Peel Tests ◽  
Bulge Formation

In this work, peel tests inside the chamber of an ESEM ( in situ peel tests) are described with heat-sealed test specimens of packaging systems made of multilayer films that simulate different flexible packaging types, according to the packaging line used. The in situ peel tests provided evidence to describe the influence of three different main aspects of the packaging process in relation to the opening behavior of the sealing packages. The investigated aspects are the peel angle, the alignment angle between the orientation of the multilayer films and the seal, and the bulge formation as a consequence of inadequate sealing parameters. In situ peel tests enabled the differentiation between peel angle and local (micro) peel angle, which results from the overall stiffness of the multilayer structure film. Alignment angles of 90° and 45° were found to produce similar opening forces. Images showing the formation of various new local micro fissures on new planes during the in situ peel test explained how the opening force can be dramatically increased during the tearing of two sealed multilayer films.

Elasto-Plastic Analysis of the Peel Test for Thin Film Adhesion

1988 ◽  
Vol 110 (3) ◽  
pp. 266-273 ◽  
Author(s):  
Kyung-Suk Kim ◽  
Junglhl Kim
Keyword(s):  
Fracture Toughness ◽  
Interfacial Crack ◽  
Peel Test ◽  
Interfacial Fracture ◽  
Peel Strength ◽  
Interfacial Fracture Toughness ◽  
Cu Films ◽  
Film Adhesion ◽  
Thin Film Adhesion ◽  
Elastoplastic Bending

Analyses have been made to extract the objective interfacial fracture toughness from the peel strength of very thin metallic films. An elastoplastic bending model of the adherend film has been employed in the analyses applying the fracture mechanics concept of steady-state interfacial crack growth. The analytic result finally shown is a universal peel diagram where the objective interfacial fracture toughness is readily readable when the peel strength is known. Experimental results for Cu films on Si and polyimide substrate systems with a Cr interface are also presented.

A New Method for Measuring the Bond Strength of Electrofusion Joint

2013 ◽  
Author(s):  
Jinyang Zheng ◽  
Dongsheng Hou ◽  
Jun Shi ◽  
Shunli Lu ◽  
Jianfeng Shi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Peel Test ◽  
High Strength ◽  
New Method ◽  
Pipeline System ◽  
Welding Defects ◽  
Good Concentration ◽  
Normal Method ◽  
Composite Pipes ◽  
Peel Tests

Electrofusion (EF) technique is very widely used in connecting polyethylene and its composite pipes. Safety of pipeline system depends on the quality of joints. For EF joints, the quality is characterized by the bond strength of welding interface. Peel test is a normal method for measuring the bond strength for EF joints. In our previous study (PVP2012-78655), we used the peel test to analyze the bond strength for EF joints with cold welding defects by calculating the bonding energy of fusion interface. However, in most well electrofused joints, test specimens fail in the pipe, rather than the fusion interface. As a result, it is difficult to determine the optimum welding conditions with the method of peel test. In this paper, a new method for measuring the bond strength of EF joint is proposed. A set of horizontal apparatus is designed and specific improved test means are introduced. Test results are then presented, which proves the effectiveness of the new method for high strength joints and in reducing pipe deformations. Finally, criteria to estimate the bond strength of joints are investigated. A comparison is made between the criterion of mean percentage decohesion presented in ISO 13954 and the criterion of normalized decohesion energy, which reveals that the latter one is more practical in statistics for peel tests, with better normality, a good concentration of data and facility to rank EF joints of different types.

scholarly journals Interlaminar adhesion assessment of carbon-epoxy laminates under salt water ageing using peel tests

2018 ◽  
Vol 233 (8) ◽  
pp. 1555-1563 ◽  
Author(s):  
Marcio M Arouche ◽  
Sandip Budhe ◽  
Mariana D Banea ◽  
Sofia Teixeira de Freitas ◽  
Silvio de Barros
Keyword(s):  
Composite Laminates ◽  
Salt Water ◽  
Chemical Characterization ◽  
Microscopic Analysis ◽  
Peel Test ◽  
Peel Strength ◽  
Water Tank ◽  
Electron Microscopic ◽  
Peel Tests ◽  
Fibre Matrix

The aim of this study is to assess the interlaminar adhesion of carbon-epoxy laminates under salt water condition. Carbon-epoxy laminate specimens were immersed in a salt water tank for 60 days. Some specimens were then dried at room temperature for 280 days, until recovering their initial weight. Specimens were tested using the composite peel test, an adaptation of the floating roller peel tests for composite materials. The results showed a degradation of peel strength in some areas due to the ageing process. The drying process did not affect the test results. A scanning electron microscopic analysis carried out on the fracture surface of the specimens revealed a typical mode I failure microstructure. A mixture of matrix failure and fibre/matrix interfacial failure was observed in non-aged specimens. Finally, a chemical characterization of the fracture surfaces with energy-dispersive spectroscopy confirmed the penetration of salt water in regions near the edge of the specimens. A degradation of the fibre/matrix interface adhesion was observed in affected areas. Floating roller peel tests proved to be a fast and effective method to access the interlaminar adhesion performance of composite laminates.

scholarly journals Investigating Teacher-Learner Interaction in EFL Classes a Basic Level of Learning

2017 ◽  
Vol 5 (4) ◽  
pp. 1257
Author(s):  
Asmaa' Y. Qassim
Keyword(s):  
English Language ◽  
Teacher Behavior ◽  
Test Method ◽  
Control Group ◽  
Ministry Of Education ◽  
Reliability Factor ◽  
Learner Interaction ◽  
Basic Instruction ◽  
The Impact ◽  
The Given

The current research aims at identifying the impact of teacher behavior on teacher-learner interaction in English language at the basic instruction level. The population consists of all male pupils in basic stage instruction within Kurdistan Region-Duhok city-Directorate of education, during the academic year (2013-2014). The sample for the study has been randomly chosen from the basic instruction – level 8. It consists of (32) pupils, sixteen forming the experimental group which has been taught by using Flanders Decimal System of behavior teacher-learner interaction (it has been prepared by the researcher depending on the source and other previous studies and researches so as to test the hypotheses of the current study. It has also been made valid through its presentation to a panel of experts, while the reliability factor has been computed by using the re-test method. On the other hand, sixteen pupils formed the control group which has been taught by using the Recommended Method by the Ministry of Education (henceforth RM). The t-test has been used for the equivalence of groups. Moreover, the researcher has used the tape recorder to access to the patterns of verbal interaction inside the classroom. The achievement test is the research tool for gaining the results of the experiment after being made valid and reliable. The findings show that teachers of English can make use of the given time in the class more successfully if they focus on encouraging learners (pupils) and accepting their ideas. Additionally, there is a limited influence of the variable related to the period of teaching service and place of graduation on the patterns of interaction inside the classroom as it has affected the percentage of the teacher's instant questions. Thus, it showed teacher of English is the most effective strategy in teacher-learner interaction. The research ends with some recommendations and suggestions depending on the findings of the study

Peel strength characterisation on ply/ply interface using wedge and T-peel/pull-type tests

2018 ◽  
Vol 26 (8-9) ◽  
pp. 431-445 ◽  
Author(s):  
Britto Satheesh ◽  
Maximilian Tonejc ◽  
Larissa Potakowskyj ◽  
Martin Pletz ◽  
Ewald Fauster ◽  
...  
Keyword(s):  
Material Properties ◽  
Peel Test ◽  
Peel Strength ◽  
Scanning Calorimetry ◽  
Material Interfaces ◽  
Consolidation Pressure ◽  
Peel Testing ◽  
Peel Force ◽  
Welding Properties

Thermoplastic tapes have found a prominent place in automated tape placement (ATP), due to their reduced processing time. ATP also offers significant reduction in labour; however, the most attractive aspect is the use of its welding properties. Welding or diffusion bonding is necessary for two thermoplastic materials to bond to each other through the combined effect of heating and consolidation pressure. The work published in this article shows how various thermoplastic tape materials with different material properties are bonded to each other using a direct flame-type ATP process. Contact angle and differential scanning calorimetry measurements help understanding of the processing needs of the considered materials. The samples obtained after ATP are sent for peel testing using a wedge peel test principle, so that the force required to separate the bonding is identified. A T-peel test/pull test is also employed to cross-compare peel results obtained through wedge peel testing. The main aim of the work is to study the quality of connection between the two plies with different material interfaces and also how friction might contribute to peel force when wedge peeling is used. A numerical model is also implemented to show the effects of this friction.

Evaluation of Interfacial Strength by Multi-Stages Peel Test

2004 ◽  
Vol 261-263 ◽  
pp. 483-488 ◽  
Author(s):  
Masaki Omiya ◽  
Hisahiro Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Thin Films ◽  
Interfacial Strength ◽  
Peel Test ◽  
Test Method ◽  
Dead Weight ◽  
Micro Sensor ◽  
Elastic Mismatch ◽  
Fracture Tests ◽  
Peel Tests ◽  
Phase Angles

Multi-layer thin films are widely used in micro-sensor and microelectronics products. These electronic devices contain several metal or polymer thin films and reliability of these systems is strongly dependent on the interfacial adhesion of these thin films. Due to the thermal stress, residual stress or elastic mismatch, the delamination between layers sometimes occurs. Therefore, it is important to evaluate the interfacial strength precisely. Peel tests are simple way to estimate an interfacial strength and, in fact, widely used in industrial field. Recently, a new simple but functional device for peel tests has developed in our group. This test method is called 'Multi-stages peel test'. There are two features in this device. At first, peeling tips can be observed continually and it becomes easy to measure a peeling angle. Second is that the peeling angle can be varied by attaching dead weights on the specimen. This dead weight works as a shear force at the peeling tip and the peeling angle can be changed variously. Therefore, the fracture tests under various phase angles are possible. In this paper, Multi-stages peel test is applied to the evaluation of interface strength of multi-layer thin films that are composed of Cu, Cr, PI and Si layers. By considering the energy balance during the peel test, the interfacial strength independent of the thickness can be obtained.

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