Fatigue TESTING is commonly conducted using the single-edge NOTCHED BEAM (SENB) test, which is not simple to prepare. With the widely use of Superpvae gyratory compactor with its consistent circular compacted samples, the industry is keen to find ways to utilize these samples in TESTING. Therefore, the SEMI-CIRCLE NOTCHED BEAM (SCNB) fatigue test setup was introduced. However, there are no justified design criteria and/or standard test procedure to evaluate fatigue life of asphalt mixes using SCNB. Thus, there is a critical need for understanding the effect of the significance of each controlling TESTING parameters to evaluate Superpave mixes resistance to fatigue cracking using SCNB. In this study, common TESTING parameters were investigated and the failure point due to fatigue was clearly defined. In addition, when comparing test results to the Asphalt Institute (AI) model, it was found that the cyclic load range of 30% to 60% of the ultimate strength could be utilized as an appropriate range with a loading frequency of 1 Hz, at which test results illustrated that strain rate and loading range lay within reasonable range of AI design guidelines.

Flaws, cracks, slits and other geometrical discontinuities which play as stress raiser, are among the inherent characteristics of rock masses. Due to existence of these defects, the load bearing capacity of rock masses reduces significantly. Thus, the fracture of rock masses containing geometrical discontinuities should be assessed. Some of slits on the rock components can be considered as a U-shaped notch and therefore, the assessment of rock-type U-NOTCHED sample is essential. In this paper, the in-plane shear mode (pure mode II) fracture behavior of rock part containing U-shaped notch is investigated experimentally and theoretically. Since there are some problems in generating and TESTING the circular shaped samples, in this study, a new test configuration based on a rectangular BEAM is proposed. The sample investigated in this study is the single edge U-NOTCHED BEAM (SEUNB) specimen which is loaded under skew-symmetric four-point bending. Determining the notch stress intensity factors (NSIF) via finite element method for SEUNB shows that the mode I NSIF is zero and hence pure mode II is achieved. Using two stress-based criteria (maximum tangential stress (MTS) and mean stress (MS) criteria) utilized extensively for investigating the fracture behavior of NOTCHED samples, the critical NSIF which represents the fracture resistance of NOTCHED samples, is predicted for each tested sample. The comparison between the experimental results and theoretical predictions demonstrates that both fracture criteria are able to predict the mode II fracture resistance of rock U-NOTCHED samples in an acceptable range for practical engineering project in the field of rock mechanics.

Nowadays, damage models are used to simulate and predict the failure occurrence regions in manufacturing processes. One of the most famous models that is widely used in finite element commercial codes is Johnson-Cook damage model. The aim of the present research is to determine the constants of Johnson-Cook damage model for pure commercial copper sheet. For this, three different tensile TESTING specimens (a smooth (standard) specimen and two NOTCHED specimen with different notch radii of 10 and 2 mm) were separated along with the rolling direction and tensile tests were conducted on them. The stress triaxiality was determined for each of the specimens, by using the Bridgeman equation. Next, regards to the dependency of the fracture strain to the stress triaxiality, the constants of Johnson-Cook damage model was determined. Numerical simulation was used to evaluate the satisfaction of the method used to determine the constants of Johnson-cook damage model. For this, the error in fracture strain was used as the criterion and the value of it was calculated for each of the tensile TESTING specimens. The average value of error in fracture strain for three tested specimens was obtained as of 9.68 percent that showed the satisfaction of the method used in this research to determine the constants of Johnson-Cook damage model. The results of this study can be used to simulate the manufacturing processes of the studied copper sheet.

Experimental tests were performed to study the seismic behavior and performance of modified steel chevron braced frame systems, which incorporate a vertical slotted connection (VSC) detail between the top of the braces and the floor BEAM above. The VSC detail is intended to prevent vertical load transfer to the BEAM and limit brace forces to the compressive resistance of the members. Full-scale quasi-static cyclic tests were performed on two specimens with hollow tube braces, with one specimen having the braces filled with concrete. Both frames exhibited stable, predictable behavior under cyclic loading. The VSC detail provided free vertical movement of the brace assembly during both tests. However, its flexibility created a moderate reduction in the overall lateral stiffness of the frame. The concrete-filled tube specimen sustained higher peak loads, demonstrated greater residual strength and dissipated more energy than the hollow tube specimen due to the partial inhibition of local buckling by the concrete core. It was found that the VSC chevron braced frame system is a suitable concept for use in buildings in high-risk seismic zones.

In this research, the effect of polypropylene fibers with polyolefin coating and specimen geometry on the mechanical properties of high-strength concrete (HSC) had been investigated. In this regard, two types of polypropylene fibers (monofilament and fibrillated) with three different lengths of 19, 30, and 50 mm and volume percentages of 0. 5, 1, and 1. 5 were used to fabricate two types of specimens: BEAM and semi-circular bending (SCB). The results had been collected based on an experimental program on high-strength concrete consisting of the tensile strength test, determination of the modulus of elasticity, and three-point bending test on BEAM and semi-circular bending specimens. As a result of adding fibers to HSC, the tensile strength, elasticity modulus, fracture energy and characteristics length were increased up to 42%, 71%, 90 times, and 87 times, respectively. Furthermore, by using the theory of hypothesis, it is concluded that it is possible to use a semi-circular bending specimen as an alternative of a BEAM specimen. Finally, linear regression and power relations had been fitted on the data to convert the results of the BEAM and the semi-circular bending to each other.

The use of Edge NOTCHED Disc BEAM (ENDB) sample has been proposed as a suitable geometry in performing fracture tests in different loading modes. The most important features of the ENDB samples include easy making, quick and easy sampling, simple TESTING, and the ability to examine a wide range of pure and combined loading modes. Using a wide range of fracture tests, a statistical model is proposed to predict the stress intensity factors of asphalt mixtures in terms of the pure torsion mode (mode III) loading in this study. To this end, the experiments were carried out at different temperature conditions (-5,-15 and-25 °C), different loading conditions (0. 5, 1 and 5 mm/min), and on control and modified asphalt mixtures with different percentages of polyolefin-aramid fibers. The results showed that, with increasing the fiber content and loading rate, the fracture strength increased with average 25%, while an increase in fracture toughness due to lower temperature had an effect of less than 5%. Using the Response Surface Method (RSM), the prediction model of stress intensity coefficients of asphalt mixtures was presented in the pure torsion mode. The results of the proposed models had a good correlation with the results of the conducted fracture tests.