A fracture mechanics approach to the tensile strength perpendicular to grain of dimension lumber

1973 ◽  
Vol 7 (1) ◽  
pp. 45-59 ◽  
Author(s):  
A. P. Schniewind ◽  
D. E. Lyon
Keyword(s):  
Tensile Strength ◽  
Fracture Mechanics ◽  
Dimension Lumber

scholarly journals Tensile Properties, Fracture Mechanics Properties and Toughening Mechanisms of Epoxy Systems Modified with Soft Block Copolymers, Rigid TiO2 Nanoparticles and Their Hybrids

2018 ◽  
Vol 2 (4) ◽  
pp. 72 ◽  
Author(s):  
Ankur Bajpai ◽  
Arun Alapati ◽  
Andreas Klingler ◽  
Bernd Wetzel
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Block Copolymers ◽  
Fracture Mechanics ◽  
Fracture Energy ◽  
Tio2 Nanoparticles ◽  
Plastic Zone Size ◽  
Hybrid Nanocomposites ◽  
Tensile Fracture ◽  
Toughening Mechanisms

The effect of the hybridization of a triblock copolymer and a rigid TiO2 nanofiller on the tensile, fracture mechanics and thermo-mechanical properties of bisphenol F based epoxy resin were studied. The self-assembling block copolymer, constituted of a center block of poly (butyl acrylate) and two side blocks of poly (methyl) methacrylate-co-polar co-monomer was used as a soft filler, and TiO2 nanoparticles were employed as rigid modifiers. Toughening solely by block copolymers (BCP’s) led to the highest fracture toughness and fracture energy in the study, KIc = 2.18 MPa·m1/2 and GIc = 1.58 kJ/m2. This corresponds to a 4- and 16-fold improvement, respectively, over the neat reference epoxy system. However, a reduction of 15% of the tensile strength was observed. The hybrid nanocomposites, containing the same absolute amounts of modifiers, showed a maximum value of KIc = 1.72 MPa·m1/2 and GIc = 0.90 kJ/m2. Yet, only a minor reduction of 4% of the tensile strength was observed. The fracture toughness and fracture energy were co-related to the plastic zone size for all the modified systems. Finally, the analysis of the fracture surfaces revealed the toughening mechanisms of the nanocomposites.

scholarly journals Moravian greywacke – evaluation of fracture, strength and deformability properties

2019 ◽  
Vol 133 ◽  
pp. 02003
Author(s):  
Martin Závacký ◽  
Tomáš Majda ◽  
Iva Rozsypalová ◽  
Jan Štefaňák
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fracture Mechanics ◽  
Construction Industry ◽  
Rock Type ◽  
High Strength ◽  
Mean Value ◽  
Raw Material ◽  
Bending Test ◽  
Compression Tests

This contribution brings overview of mechanical properties of greywacke with focus on fracture mechanics parameters. Investigated rock type is clastic sediment, relatively widespread in Moravia region. The rock type is significantly utilized in construction industry. For purposes of this study, Kobeřice quarry was selected as sampling locality. Mechanical properties were investigated by deformation controlled 3-point bending test. Chevron notch was created on specimens in order to study fracture mechanics parameters. Moreover, deformation controlled uniaxial compression tests were carried out, as well. Specimens were equipped with strain gauges; thus, elastic modulus and the Poisson’s ratio could be determined. Splitting tensile test was employed in order to determine tensile strength. Mean value of fracture toughness KIC was determined to 1.85 MPa·m0.5. Mean value of uniaxial compressive strength was observed at level of 211 MPa and tensile strength reached 19.4 MPa. Hence, the tested greywacke was considered as high strength rock. Brittle type of failure occurred during the tests. The obtained results were compared with values reported for clastic sediments from several localities in the Czech Republic. Moravian greywacke reached significantly high strength in comparison to other clastic sedimentary rocks and can be considered as valuable raw material for purposes of construction industry.

A Novel Application of the Principles of Linear Elastic Fracture Mechanics (LEFM) to the Fatigue Behavior of Tendon Tissue

2004 ◽  
Vol 126 (5) ◽  
pp. 641-650 ◽  
Author(s):  
Samer M. Adeeb ◽  
Michelle L. Zec ◽  
Gail M. Thornton ◽  
Cyril B. Frank ◽  
Nigel G. Shrive
Keyword(s):  
Tensile Strength ◽  
Cyclic Loading ◽  
Fracture Mechanics ◽  
Ultimate Tensile Strength ◽  
Fatigue Behavior ◽  
Cyclic Stress ◽  
Linear Elastic Fracture Mechanics ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Number Of Cycles

Background: Experiments on the fatigue of tendons have shown that cyclic loading induces failure at stresses lower than the ultimate tensile strength (UTS) of the tendons. The number of cycles to failure Nf has been shown to be dependent upon the magnitude of the applied cyclic stress. Method of approach: Utilizing data collected by Schechtman (1995), we demonstrate that the principles of Linear Elastic Fracture Mechanics (LEFM) can be used to predict the fatigue behavior of tendons under cyclic loading for maximum stress levels that are higher than 10% of the ultimate tensile strength (UTS) of the tendon (the experimental results at 10% UTS did not fit with our equations). Conclusions: LEFM and other FM approaches may prove to be very valuable in advancing our understanding of damage accumulation in soft connective tissues.

Strain Rate Effects on the Tensile Strength of Concrete as Predicted by Thermodynamic and Fracture Mechanics Models

1985 ◽  
Vol 64 ◽  
Author(s):  
Hans W. Reinhardt
Keyword(s):  
Tensile Strength ◽  
Fracture Mechanics ◽  
Strain Rate ◽  
High Stress ◽  
Stress Rate ◽  
Engineering Practice ◽  
Strain Rate Effects ◽  
Linear Fracture Mechanics ◽  
Linear Fracture ◽  
Rate Effects

ABSTRACTModels are presented and discussed which predict the influence of stress rate or strain rate on the tensile strength of concrete. Three of them are based on linear fracture mechanics and two on thermodynamics. It is shown that four models are appropriate and useful in the low to medium stress rate whereas two can predict realistic values at high stress rates. Finally a proposal is made how to apply the knowledge to engineering practice.

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