scholarly journals Bonding of plywood 

2016 ◽  
Vol 62 (No. 4) ◽  
pp. 198-204
Author(s):  
M. Brožek

The contribution contains results of bonded joints strength tests. The tests were carried out according to the modified standard ČSN EN 1465 (66 8510):2009. The spruce three-ply wood of 4 mm thickness was used for bonding according to ČSN EN 636 (49 2419):2013. The test samples of 100 × 25 mm size were cut out from a semi-product of 2,440 × 1,220 mm size in the direction of its longer side (angle 0°), in the oblique direction (angle 45°) and in the direction of its shorter side (crosswise – angle 90°). The bonding was carried out using eight different domestic as well as foreign adhesives according to the technology prescribed by the producer. All used adhesives were designated for wood bonding. At the bonding the consumption of the adhesive was determined. After curing, the bonded assemblies were loaded using a universal tensile-strength testing machine up to the rupture. The rupture force and the rupture type were registered. Finally, the technical-economical evaluation of the experiments was carried out. 

2019 ◽  
Vol 108 ◽  
pp. 26-38
Author(s):  
ŁUKASZ MATWIEJ ◽  
ROBERT KŁOS ◽  
MIROSŁAW BONOWSKI

Design of a snap connector to connect panel elements. The aim of this study was to design, manufacture and verify the tensile strength of a prototype snap connector to be used to connect panel elements. Firstly, analyses were conducted on solutions of commercially available designs for connectors invisible from the cabinet’s outside and those with minimized visibility. While searching for the best concept of connector design, three proposals were prepared, of which – after thorough analysis of design – one concept was selected. In the next step, the adopted solution was improved so that the connector met the previously formulated design requirements. In the course of further analyses, the causes and effects of failure were verified in order to limit or eliminate potential defects. In the next stage of the study, numerical calculations were conducted for the nut and the connector, concerning tensile strength, using the Autodesk Simulation Multiphysics program. After a prototype connector was manufactured, tensile strength tests were conducted on the connector using a strength testing machine. Experiments verified the correctness of the developed design in terms of geometry and the physico-mechanical properties of materials of individual elements, and resulted in possible changes proposed in the design of the final connector product.


Author(s):  
A. A. Gorbatovskiy

The article presents results of strength tests of bismuth telluride prismatic samples obtained by growing crystals. These crystals have semiconductor properties and are used in the heat machines, the run-ability of which largely depends on the strength of crystals. Data available in the literature are significantly different from each other. It has been shown that, the most consistent strength tests results are obtained in case of bend testing. The measurement results of the elasticity modulus and tensile strength are given. For tests, an INSTRON testing machine with maximum direct stress of the 1000 H was used.


2016 ◽  
Vol 61 (No. 3) ◽  
pp. 134-139
Author(s):  
M. Brožek

The paper presents the results of strength tests of joints made using six different adhesives destined by their producers for bonding wood. Bonded samples were made from seven sorts of wood commonly growing in the Czech Republic, namely ash, beach, cherry, maple, pine, spruce and walnut. From semi-products (boards, planks, squared timber logs) the test samples of dimensions 25 × 100 mm and 4 mm thickness were cut out in the direction of year rings. Always two samples were bonded together so that their overlap was of 12.5 mm. All these assemblies were loaded using the universal testing machine up to their rupture. The rupture force and the rupture type (rupture in the joint, in the bonded material) were registered. The aim of the tests was to assess the influence of the used adhesive on the bonded joint strength at different woods, to assess the variability of the adhesive consumption at the manual adhesive application by different workers and to determine costs for bonding of different woods using different adhesives. From the results it follows that between six tested adhesives used for bonding of seven sorts of wood, considerable differences exist not only as regards their price, but also their quality. From the results it also follows that the manual adhesive application is very unequal, because it depends on the dexterity and care of the worker. Next, the costs for bonding of different woods using different adhesives were determined.


2017 ◽  
Vol 43 (2) ◽  
pp. 87-93 ◽  
Author(s):  
Marcos Alexandre Fadanelli ◽  
Flávia Lucisano Botelho do Amaral ◽  
Roberta Tarkany Basting ◽  
Cecilia Pedroso Turssi ◽  
Bruno Salles Sotto-Maior ◽  
...  

The purpose of this study was to evaluate the effects of steam autoclave sterilization on the tensile strength of two types of resin cements used to bond customized CAD/CAM zirconia abutments onto titanium bases. Forty sets of zirconia abutments cemented to screwed titanium bases of implants analogs were divided into 4 groups (n = 10). Two groups were treated with a conventional chemically activated resin cement (ML, Multilink Ivoclar Vivadent) and the other two groups with a self-adhesive dual resin cement (RelyX U200, 3M ESPE). One group from each cement was submitted to steam autoclaving. The autoclave sterilization cycle was performed after 72 hours of cementation for 15 minutes at 121°C and 2.1 Kgf/cm2. The samples were subjected to tensile strength testing in a universal testing machine (200 Kgf, 0.5 mm/min), from which the means and standard deviations were obtained in Newtons. Results showed (via ANOVA and Tukey's test; α = 0.05) that in the absence of steam autoclaving, no difference was observed in tensile strength between the cements tested: ML: 344.87 (93.79) and U200: 280 (92.42) (P = .314). Steam autoclaving, however, significantly increased tensile strength for the ML: 465.42 (87.87) compared to U200: 289.10 (49.02) (P < .001). Despite the significant increase in the ML samples (P = .013), autoclaving did not affect the tensile strength of the U200 samples (P > 0.05). The authors concluded that steam autoclaving increases the mean tensile strength of the chemically activated cement compared to the dual-cure self-adhesive cement. The performance of both cements evaluated was similar if the sterilization step was disconsidered.


1994 ◽  
Vol 59 (4) ◽  
pp. 709-723 ◽  
Author(s):  
Mark A. Neupert

The measurement of ceramic strength is an important source of evidence for assessing any pottery technology. However, the adoption of strength testing within comprehensive ceramic analyses in archaeology has been hindered by the absence of a reliable format for testing archaeological specimens. This paper presents results of research undertaken to develop the ball-on-three-ball test, which measures the tensile strength of archaeological, ethnographic, and experimental ceramics in biaxial flexure. Laboratory experiments demonstrate that the test produces reliable and accurate results largely unaffected by the irregularities of sherd-shaped specimens. In an example from the prehistoric Southwest, strength tests are used to investigate technological change in the Cibola White Ware sequence and the role of strength in the formation of archaeological assemblages. It is suggested that the development of a versatile, dependable technique can help to move strength testing out of experimental laboratories and into mainstream ceramic analyses.


Author(s):  
Weronika Kowalik ◽  
Kinga Pachuta ◽  
Jerzy Jeznach

Abstract The stabilization and protection of shorelines using the broadleaf cattail and reed sweet grass. The article presents the results of studies on the mechanical properties of the broadleaf cattail Typha latifolia and reed sweet grass Glyceria maxima. The necessary study samples were collected from Lake Urszulewskie near Sierpc, Poland. The experiment was conducted using an Instron 5966 universal tensile strength testing machine. Tensile forces and the tensile strength of the individual parts of both plant species, i.e. below-ground stems (rhizomes), base of the stem and above-ground stems, were determined and compared with each other. The STATISTICA program was used for analysis. The calculated tensile strength values were compared to data of selected tree, shrub and plant species provided by other authors.


2015 ◽  
Vol 26 (6) ◽  
pp. 637-641
Author(s):  
Raniel Fernandes Peixoto ◽  
Caio Rocha de Aguiar ◽  
Eduardo Santana Jacob ◽  
Ana Paula Macedo ◽  
Maria da Gloria Chiarello de Mattos ◽  
...  

This research evaluated the influence of temporary cements (eugenol-containing [EC] or eugenol-free [EF]) on the tensile strength of Ni-Cr copings fixed with self-adhesive resin cement to the metal coronal substrate. Thirty-six temporary crowns were divided into 4 groups (n=9) according to the temporary cements: Provy, Dentsply (eugenol-containing), Temp Cem, Vigodent (eugenol-containing), RelyX Temp NE, 3M ESPE (eugenol-free) and Temp Bond NE, Kerr Corp (eugenol-free). After 24 h of temporary cementation, tensile strength tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min and 1 kN (100 kgf) load cell. Afterwards, the cast metal cores were cleaned by scraping with curettes and air jet. Thirty-six Ni-Cr copings were cemented to the cast metal cores with self-adhesive resin cement (RelyX U200, 3M ESPE). Tensile strength tests were performed again. In the temporary cementation, Temp Bond NE (12.91±2.54) and Temp Cem (12.22±2.96) presented the highest values of tensile strength and were statistically similar to each other (p>0.05). Statistically significant difference (p<0.05) was observed only between Provy (164.44±31.23) and Temp Bond NE (88.48±21.83) after cementation of Ni-Cr copings with self-adhesive resin cement. In addition, Temp Cem (120.68±48.27) and RelyX Temp NE (103.04±26.09) showed intermediate tensile strength values. In conclusion, the Provy eugenol-containing temporary cement was associated with the highest bond strength among the resin cements when Ni-Cr copings were cemented to cast metal cores. However, the eugenol cannot be considered a determining factor in increased bond strength, since the other tested cements (1 eugenol-containing and 2 eugenol-free) were similar.


CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 370-384
Author(s):  
Hossein Noorvand ◽  
Kamil Kaloush ◽  
Jose Medina ◽  
Shane Underwood

Asphalt aging is one of the main factors causing asphalt pavements deterioration. Previous studies reported on some aging benefits of asphalt rubber mixtures through laboratory evaluation. A field observation of various pavement sections of crumb rubber modified asphalt friction courses (ARFC) in the Phoenix, Arizona area indicated an interesting pattern of transverse/reflective cracking. These ARFC courses were placed several years ago on existing jointed plain concrete pavements for highway noise mitigation. Over the years, the shoulders had very noticeable and extensive cracking over the joints; however, the driving lanes of the pavement showed less cracking formation in severity and extent. The issue with this phenomenon is that widely adopted theories that stem from continuum mechanics of materials and layered mechanics of pavement systems cannot directly explain this phenomenon. One hypothesis could be that traffic loads continually manipulate the pavement over time, which causes some maltenes (oils and resins) compounds absorbed in the crumb rubber particles to migrate out leading to rejuvenation of the mastic in the asphalt mixture. To investigate the validity of such a hypothesis, an experimental laboratory testing was undertaken to condition samples with and without dynamic loads at high temperatures. This was followed by creep compliance and indirect tensile strength testing. The results showed the higher creep for samples aged with dynamic loading compared to those aged without loading. Higher creep compliance was attributed to higher flexibility of samples due to the rejuvenation of the maltenes. This was also supported by the higher fracture energy results obtained for samples conditioned with dynamic loading from indirect tensile strength testing.


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