Experimental and theoretical analysis of in-plane cohesive testing of paperboard

2016 ◽  
Vol 26 (6) ◽  
pp. 895-918 ◽  
Author(s):  
Johan Tryding ◽  
Gustav Marin ◽  
Mikael Nygårds ◽  
Petri Mäkelä ◽  
Giulio Ferrari
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Theoretical Analysis ◽  
Fracture Energy ◽  
Morse Potential ◽  
Cohesive Failure ◽  
Cohesive Stress ◽  
Maximum Slope ◽  
Tension Tests ◽  
Short Span

In-plane cohesive failure of paperboard was characterized by short-span uniaxial tension tests. Six paperboards' qualities were experimentally investigated, from which cohesive stress–widening curves were extracted. A fracture energy was defined, expressed in the tensile strength and maximum slope of the cohesive stress–widening relation. Analytical cohesive relations were derived based on the tensile strength and maximum slope, utilizing the Morse potential for diatomic molecules. It was experimentally found that the maximum slope and fracture energy depend on the tensile strength. The ratio of the maximum slope to the elastic modulus (stable length) was shown to be independent of the tensile strength.

scholarly journals Finite Element Study on the Shear Capacity of Traditional Joints between Walls Made of AAC Masonry Units

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4035
Author(s):  
Marcin Kozłowski ◽  
Iwona Galman ◽  
Radosław Jasiński
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Numerical Model ◽  
Fracture Energy ◽  
Shear Capacity ◽  
Nonlinear Behaviour ◽  
Structural Behaviour ◽  
Finite Element Software ◽  
Masonry Units

This paper presents the development of a numerical model aimed at the simulation of nonlinear behaviour of traditional joints between walls made of autoclaved aerated concrete (AAC) masonry units. Nonlinear behaviour and cracking of AAC and mortar were simulated using the concrete damaged plasticity (CDP) model available in the ABAQUS finite element software. The paper also presents and discusses the results of an experimental campaign involving testing six T-shaped, monosymmetric samples with traditional joints between walls loaded in shear. The results were used to validate the numerical model. The validation confirmed that the model is capable of producing accurate results and predicting the structural behaviour with a reasonably good accuracy in elastic and post-elastic stages. Furthermore, a sensitivity study was conducted, in which the variation of elastic modulus, Poisson’s ratio, tensile strength, compression strength and fracture energy of AAC was investigated. Results showed that the variation of elastic modulus, tensile strength and fracture energy is most critical to the structural behaviour of the model, while variation of the remaining parameters has a negligible effect on the results.

The Concrete Fracture Performance Response to the Interface Transition Zone Parameters Based on Mesoscopic Simulation

2012 ◽  
Vol 170-173 ◽  
pp. 3482-3486 ◽  
Author(s):  
Min Du ◽  
Liu Jin ◽  
Xiu Li Du ◽  
Yan Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Fracture Energy ◽  
Transition Zone ◽  
Failure Process ◽  
Aggregate Model ◽  
Fracture Modes ◽  
Random Aggregate ◽  
Interface Transition Zone

The interface transition zone (ITZ) has a significant impact on the concrete’s mechanical properties and fracture modes. For the influence of ITZ’s strength and elastic modulus, the extended finite element method (XFEM) is adopted to simulate the mesostructure failure process by virtue of random aggregate model under uniaxial tension. The results show that ITZ’s strength and elastic modulus have a certain effect on the mechanical properties and fracture modes. With the tensile strength of ITZ increasing, the fractured modes transit from single coalescent crack to multiple non-coalescent cracks and the fracture energy increases, the ductility of concrete is enhanced. With the elastic modulus of ITZ increasing, the concrete’s elastic modulus increases, the tensile strength and the fracture energy decrease.

scholarly journals The Effect of Pre-Bond Contamination by Thermal Degradation and De-Icing Fluid on the Tensile Strength of Scarf Composite Bonded Joints

2021 ◽  
Vol 5 (7) ◽  
pp. 168
Author(s):  
Konstantinos Tserpes ◽  
Elli Moutsompegka
Keyword(s):  
Tensile Strength ◽  
Thermal Degradation ◽  
Repair Process ◽  
Bonded Joints ◽  
Cohesive Failure ◽  
Lap Shear ◽  
Tension Tests ◽  
Reference Samples ◽  
Different Levels ◽  
Combined Contamination

The synergistic effect of pre-bond contamination by thermal degradation and de-icing fluid on the tensile behavior of scarf composite bonded joints has been investigated experimentally. The contamination types considered are related to the repair process of composite aircraft structures. Three contamination scenarios have been considered: namely, thermal degradation (TD) and a combination of thermal degradation with two different levels of de-icing fluid (TD+DI1 and TD+DI2). DI2 is more severe than DI1. Contamination has been applied to one of the adherents while the other one has been intentionally left intact. Tension tests have been conducted on single-lap shear specimens. The experimental results were compared with the reference samples (REF) showing an increase in tensile strength for the TD specimens and a decrease in tensile strength for the TD+DI1 and TD+DI2 specimens. After the tension tests, the failure surfaces were evaluated to get a better insight of the failure mechanisms of the bondline and to assess the effect of contamination. The TD specimens presented an increased cohesive failure which is consistent with the increase of the failure load, while the combined contamination caused the failure of the composite adherents which again is consistent with the decrease of tensile strength of the scarf specimens.

scholarly journals Properties of a Lightweight Fly Ash–Slag Alkali-Activated Concrete with Three Strength Grades

2021 ◽  
Vol 11 (2) ◽  
pp. 766
Author(s):  
Huailiang Wang ◽  
Yuhui Wu ◽  
Lang Wang ◽  
Huihua Chen ◽  
Baoquan Cheng
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Fracture Energy ◽  
Lightweight Concrete ◽  
Pulse Velocity ◽  
Normal Weight ◽  
Splitting Tensile Strength ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Lightweight alkali-activated concrete (LAAC) is a type of highly environmentally friendly concrete, which can provide the benefits of both alkali-activated material and lightweight concrete. The study aimed to investigate the influence of different water/solid (W/S) ratios on the properties of normal-weight/lightweight fly ash–slag alkali-activated concrete manufactured at ambient temperature. The relative performance of the alkali-activated concrete (AAC) mixes with limestone and sintered fly ash lightweight aggregates as the coarse aggregates was also compared to the conventional ordinary Portland cement (OPC) concrete mix in terms of their compressive stress–strain relationship, splitting tensile strength and fracture parameters. The morphologies and microstructure of the four types of interfacial transition zones (ITZs) were characterized by scanning electron microscopy (SEM). Results indicated that the AAC had a higher tensile strength, stress intensity factor, brittleness and lower elastic modulus than its cement counterpart. With the decrease in the W/S ratio, the density, compressive and tensile strength, ultrasonic pulse velocity, fracture energy, brittleness and elastic modulus of the AAC increase. However, the influence of the W/S ratio on the mechanical properties of the LAAC with lightweight porous aggregates was less than that of the normal-weight AAC. Predictive models of the splitting tensile strength, fracture energy and elastic modulus of the AAC were also suggested, which were similar to those of the OPC concrete. Furthermore, the microstructure investigation showed that no wall effect occurred in the ITZ of the AAC. The ITZ structure of the hardened AAC was also more compact and uniform than that of the OPC concrete.

scholarly journals Three-dimensional thermomechanical converting of CTMP substrates: effect of bio-based strengthening agents and new mineral filling concept

Cellulose ◽  
2021 ◽  
Vol 28 (15) ◽  
pp. 9751-9768
Author(s):  
Teija Laukala ◽  
Sami-Seppo Ovaska ◽  
Ninja Kerttula ◽  
Kaj Backfolk
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Three Dimensional ◽  
Microfibrillated Cellulose ◽  
New Mineral ◽  
Thermomechanical Pulp ◽  
Cationic Starch ◽  
Precipitated Calcium Carbonate ◽  
Filling Method ◽  
Positive Effect

AbstractThe effects of bio-based strengthening agents and mineral filling procedure on the 3D elongation of chemi-thermomechanical pulp (CTMP) handsheets with and without mineral (PCC) filling have been investigated. The 3D elongation was measured using a press-forming machine equipped with a special converting tool. The strength of the handsheets was altered using either cationic starch or microfibrillated cellulose. Precipitated calcium carbonate (PCC) was added to the furnish either as a slurry or by precipitation of nano-sized PCC onto and into the CTMP fibre. The 3D elongation of unfilled sheets was increased by the dry-strengthening agents, but no evidence on the theorised positive effect of mineral fill on 3D elongation was seen in either filling method. The performance of the strengthening agent depended on whether the PCC was as slurry or as a precipitated PCC-CTMP. The starch was more effective with PCC-CTMP than when the PCC was added directly as a slurry to the furnish, whereas the opposite was observed with microfibrillated cellulose. The 3D elongation correlated positively with the tensile strength, bursting strength, tensile stiffness, elastic modulus and bending stiffness, even when the sheet composition was varied, but neither the strengthening agent nor the method of PCC addition affected the 3D elongation beyond what was expectable based on the tensile strength of the sheets. Finally, mechanisms affecting the properties that correlated with the 3D elongation are discussed.

scholarly journals Clay-Based Products Sustainable Development: Some Applications

2021 ◽  
Vol 13 (3) ◽  
pp. 1364
Author(s):  
Michele La Noce ◽  
Alessandro Lo Faro ◽  
Gaetano Sciuto
Keyword(s):  
Sustainable Development ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Basalt Fibers ◽  
Future Studies ◽  
Clay Bricks ◽  
Brick Powder ◽  
Alkaline Resistance ◽  
Raw Earth

Clay has a low environmental impact and can develop into many different products. The research presents two different case studies. In the first, the clay is the binder of raw earth doughs in order to produce clay-bricks. We investigate the effects of natural fibrous reinforcements (rice straws and basalt fibers) in four different mixtures. From the comparison with a mix without reinforcements, it is possible to affirm that the 0.40% of basalt fibers reduce the shrinkage by about 25% and increase the compressive strength by about 30%. Future studies will focus on identifying the fibrous effects on tensile strength and elastic modulus, as well as the optimal percentage of fibers. In the second study, the clay, in form of brick powder (“cocciopesto”), gives high alkaline resistance and breathability performance, as well as rendering and color to the plaster. The latter does not have artificial additives. The plaster respects the cultural instance of the original building. The research underlines how the use of a local (and traditional) material such as clay can be a promoter of sustainability in the contemporary building sector. Future studies must investigate further possible uses of clay as well as a proper regulatory framework.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

scholarly journals Numerical Studies of the Effects of Water Capsules on Self-Healing Efficiency and Mechanical Properties in Cementitious Materials

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Haoliang Huang ◽  
Guang Ye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Cementitious Materials ◽  
Self Healing ◽  
Negative Effects ◽  
Numerical Studies ◽  
Healing Efficiency ◽  
The Impact ◽  
Positive Effect

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.

Graphite/Bio-Based Epoxy Composites: The Mechanical Properties Interface

2015 ◽  
Vol 799-800 ◽  
pp. 115-119 ◽  
Author(s):  
Anika Zafiah M. Rus ◽  
Nur Munirah Abdullah ◽  
M.F.L. Abdullah ◽  
M. Izzul Faiz Idris
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Filler Content ◽  
Weight Percent ◽  
Epoxy Composites ◽  
Elongation At Break ◽  
Graphite Content ◽  
Dispersion Condition ◽  
Strong Interfacial Bonding

Graphite reinforced bio-based epoxy composites with different particulate fractions of graphite were investigated for mechanical properties such as tensile strength, elastic modulus and elongation at break. The graphite content was varied from 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.% by weight percent in the composites. The results showed that the mechanical properties of the composites mainly depend on dispersion condition of the treated graphite filler, aggregate structure and strong interfacial bonding between treated graphite in the bio-based epoxy matrix. The composites showed improved tensile strength and elastic modulus with increase treated graphite weight loading. This also revealed the composites with increasing filler content was decreasing the elongation at break.

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