Comparison of Peel and Lap Shear Bond Strengths for Elastic Joints with and without Residual Stresses

1989 ◽  
Author(s):  
A. N. Gent ◽  
C. W. Lin
Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2473 ◽  
Author(s):  
Xiuwen Liu ◽  
Michael Pujari-Palmer ◽  
David Wenner ◽  
Philip Procter ◽  
Gerard Insley ◽  
...  

The aim of the present study was to evaluate the soft tissue bond strength of a newly developed, monomeric, biomimetic, tissue adhesive called phosphoserine modified cement (PMC). Two types of PMCs were evaluated using lap shear strength (LSS) testing, on porcine skin: a calcium metasilicate (CS1), and alpha tricalcium phosphate (αTCP) PMC. CS1 PCM bonded strongly to skin, reaching a peak LSS of 84, 132, and 154 KPa after curing for 0.5, 1.5, and 4 h, respectively. Cyanoacrylate and fibrin glues reached an LSS of 207 kPa and 33 kPa, respectively. αTCP PMCs reached a final LSS of ≈110 kPa. In soft tissues, stronger bond strengths were obtained with αTCP PMCs containing large amounts of amino acid (70–90 mol%), in contrast to prior studies in calcified tissues (30–50 mol%). When αTCP particle size was reduced by wet milling, and for CS1 PMCs, the strongest bonding was obtained with mole ratios of 30–50% phosphoserine. While PM-CPCs behave like stiff ceramics after setting, they bond to soft tissues, and warrant further investigation as tissue adhesives, particularly at the interface between hard and soft tissues.


2017 ◽  
Vol 74 (5) ◽  
pp. 410-419
Author(s):  
Vera Stojanovska ◽  
Chris Ivanoff ◽  
Ilijana Muratovska ◽  
Lidija Popovska ◽  
Franklin Garcia-Godoy ◽  
...  

Background/Aim. The longevity of a dental restoration may be predicted to some degree by its adhesive ability, and this, in turn, can be measured by bond strength testing between restorative materials and tooth structure. The aim of this study was to test an innovative joggle lap shearing jig that integrates the tooth and the entire biomechanical unit into testing, to compare the shear bond strengths of Class I occlusal composite restorations in deep cavity preparations lined with Dycal, Dycal LC, conventional glass ionomer or resin-modified glass ionomer. The mode of failure (adhesive, cohesive, mixed) after debonding was determined by stereomicroscopy. Methods. A total of 150 standardized occlusal cavities were prepared and divided into five groups. The group I cavities (n = 30) were coated with adhesive (ExciTE?F) and filled directly with composite (TetricEvoCeram). The group II and III cavities were lined with Dycal (n = 30) or Dycal LC (n = 30) before placing composite. The groups IV and V specimens were based with Fuji IX (n = 30) or Fuji II LC (n = 30). Shear bond strengths were determined with a universal testing machine and fractured bonding sites were analyzed under stereomicroscope. The mean bond strengths were analyzed using one-way ANOVA test (p < 0.05) and the means between the groups were analyzed with Student?s t-test. Results. The shear bond strength (MPa) of composite restorations in cavities without base (23.91 ? 4.54) was higher than cavities lined with Fuji II LC (17.45 ? 2.74), Fuji IX (8.76 ? 2.57), Dycal LC (13.07 ? 1.84) or Dycal (6.12 ? 1.28). The results using the jogged lap shearing jig were consistent with the literature. Conclusion. The shear bond strength of occlusal composite restorations in deep cavities without liners was greater than cavities lined with Fuji II LC > Fuji IX > Dycal LC > Dycal.


Author(s):  
R. E. Herfert ◽  
N. T. McDevitt

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.


Author(s):  
Jorge Perdigao

In 1955, Buonocore introduced the etching of enamel with phosphoric acid. Bonding to enamel was created by mechanical interlocking of resin tags with enamel prisms. Enamel is an inert tissue whose main component is hydroxyapatite (98% by weight). Conversely, dentin is a wet living tissue crossed by tubules containing cellular extensions of the dental pulp. Dentin consists of 18% of organic material, primarily collagen. Several generations of dentin bonding systems (DBS) have been studied in the last 20 years. The dentin bond strengths associated with these DBS have been constantly lower than the enamel bond strengths. Recently, a new generation of DBS has been described. They are applied in three steps: an acid agent on enamel and dentin (total etch technique), two mixed primers and a bonding agent based on a methacrylate resin. They are supposed to bond composite resin to wet dentin through dentin organic component, forming a peculiar blended structure that is part tooth and part resin: the hybrid layer.


2002 ◽  
Vol 12 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Y. Zamachtchikov ◽  
F. Breaban ◽  
P. Vantomme ◽  
A. Deffontaine

2003 ◽  
Vol 105 ◽  
pp. 175-182 ◽  
Author(s):  
L. Delannay ◽  
R. E. Logé ◽  
Y. Chastel ◽  
P. Van Houtte
Keyword(s):  

Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.


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