The possibility of using the dynamic shear rheometer (DSR) with 4 mm parallel plates and 3 mm gap is investigated as an alternative experimental method to measure the rheological properties of ...asphalt binders at low temperature. A special butterfly silicone mold was prepared for this purpose and the corresponding testing procedure was also developed. Five different asphalt binders, which are part of two active research projects, were selected. Frequency and temperature sweep tests were conducted using the DSR with three plate–plate geometries: 4 mm, 8 mm, and 25 mm. The new testing procedure was used to measure at low temperatures. The method recently proposed by the Western Research Institute and based on DSR tests with 4 mm parallel plates and 1.75 mm gap was also used for comparison purposes. Black diagrams and Cole-Cole plots were then used to evaluate the experimental data. Complex modulus and phase angle master curves were generated, and the rheological parameters compared. Finally, the two spring, two parabolic elements, one dashpot (2S2P1D) model was selected to investigate the rheological properties of the binders. Results indicate that the proposed procedure is a simple and reliable experimental method and represents an alternative experimental option to measure and analyze the rheological properties of asphalt binders at low temperature.
The development of products in a variety of industries is now being increasingly influenced by material advancements. Many experts are looking for basic materials that are strong, light, and ...inexpensive. Solids are often rather thick, whereas light materials are weaker. To attain significant strength while lowering weight, we use composite materials. This work deals with the mixed effects of composites made by hand using an epoxy tar and a hardener along with different fiberes of chopped mate (KC), Kenaf (KA), and Kevlar (KB). Mechanical studies such as tensile (UTS), flexural (FL), impact (IM), and hardness (BHN) were conducted after creating specimens according to standard measurements.
Material developments are now playing an progressively important role in the development of produces in a variation of industries. Many experts are seeking for fundamental materials with high ...strength, low weight, and low cost. Solid solids are typically somewhat thick, while light materials have lower strength. We use composite materials to achieve great strength while reducing weight. This task deals with the mixed effect of composites constructed of Kenaf (KE), Kevlar fibres (KF), as well as chopped mate (CE) that are created by hand using an Epoxy tar and a hardener. After making varieties as per regular measurements, mechanical experiments such as Tensile (TS), Flexural (FS), impact (IS) and hardness (HN) were carried.
To improve the accuracy of a sheet metal forming simulation, the constitutive model is calibrated using results from multiaxial material testing. However, multiaxial material testing is ...time-consuming and requires specialized equipment. This study proposes two different deep neural network (DNN) approaches, a two- and three-dimensional convolutional neural network (DNN-2D and DNN-3D), to efficiently estimate biaxial stress-strain curves of aluminum alloy sheets from a digital image representing the sample's crystallographic texture. DNN-2D is designed to estimate biaxial stress-strain curves from a digital image of {111} pole figure, while DNN-3D estimates the curves from a 3D image of the texture. The two DNNs were trained using synthetic texture datasets and the corresponding biaxial stress-strain curves obtained from crystal plasticity-based numerical biaxial tensile tests. The accuracy of the two trained DNNs was examined by comparing the results from that of the numerical biaxial tensile tests. It was observed that both the DNNs could estimate biaxial stress-strain curves with high accuracy. Though DNN-3D provides with a better estimation than DNN-2D, it displays lower computational efficiency. Thus, the two DNNs and their training procedures offer a new and efficient method to provide virtual data for material modeling.
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•DNNs were used to estimate biaxial stress-strain curves of aluminum alloy sheets.•Pole figure images and 3D orientation maps were explored as input data.•DNNs were as accurate as numerical biaxial tensile tests, but much faster.•A new approach to virtual data generation for material modeling was demonstrated.
•Study investigates transverse material property gradient through bamboo culm wall.•Transverse behaviour does not behave as a fibre-reinforced composite material.•Variation if morphology through culm ...wall identified using microscopy.•Culm wall morphology coupled with material property assessment.
Performance of full-culm bamboo structures is dominated by longitudinal splitting behaviour, often exacerbated by connection details. This behaviour is a function of the transverse properties of this highly orthotropic material. Considerable study of the longitudinal properties of bamboo is available in which it is often concluded that bamboo may be considered as a fibre-reinforced composite material and material properties may be assessed using rule-of-mixture methods. Nonetheless, few studies have addressed the transverse properties of the bamboo culm wall, despite these largely governing full-culm behaviour. This study investigated the transverse material property gradient through the culm wall and attempts to connect the mechanical results to physical observations and phenomena. Most importantly, the study demonstrates that the complex transverse behaviour of bamboo does not appear to behave as a classic fibre-reinforced composite material in the direction transverse to the fibres. In this study, five different bamboo species, Phyllostachys edulis, Phyllostachys bambusoides, Phyllostachys meyeri, Phyllostachys nigra, and Bambusa stenostachya were tested using a modification of the flat-ring flexure test to obtain a measure of the transverse tensile capacity of the bamboo. Microscopy analyses are used to qualitatively describe the culm wall architecture and to quantitatively assess the failure modes through the culm wall thickness.
•Experimental tests have been performed on 57 extruded aluminium bars.•One and two stages Ramberg-Osgood models have been provided for each tested aluminium alloy.•The low cycle fatigue curves have ...been obtained for 6060, 6082 and 7075 alloys.•Ductility and dissipation have been evaluated in the cyclic tests.•The skeleton curves are derived for each aluminium alloys by means of the incremental cyclic tests.
In the present paper an extensive experimental campaign is carried out on 5000, 6000 and 7000 aluminium series through monotonic and cyclic tests. The research is part of a collaboration between the Universities of Salerno and Naples “Federico II”involvedfor several decades in the development of the Eurocode recommendation regarding the aluminium alloys for structural purposes. The experimental program is composed of 3 monotonic experiments for each aluminium alloy, 29 low-cycle fatigue tests for 6060, 6082 and 7075 alloys and 10 incremental cyclic tests under different loading cycles for all tested alloys.
The main purpose of this campaign is the characterization of such alloys not only in terms of the well-known stress–strain curve while in terms of low cycle fatigue, cyclic hardening, dissipated energy and plastic fracture, to achieve more information about the non linear behaviour which can be exhibited, as an example, under seismic loading. In fact, since now, the largest part of the research has been mainly focused on the behaviour of such materials under a large number of cyclesinelastic range thus neglecting the potential benefits in exploiting the large dissipative capacity of such alloys.
Moreover, the collected information could be of fundamental importance in the framework of the revision of the new Eurocode 8 which presents, for the first time, a section devoted to the seismic design of structures made of aluminium alloys. The accurate knowledge of the random material variability and cyclic hardening could be helpful for the setting up of the coefficients to be used for the application of the hierarchy criteria.
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