Download Free Discrete Element Modelling Of Compression Tests For An Idealised Asphalt Mixture Book in PDF and EPUB Free Download. You can read online Discrete Element Modelling Of Compression Tests For An Idealised Asphalt Mixture and write the review.

This book (including a 969 pages full paper USB device) deals with the geotechnics of roads, railways and airfields. Providing economic and sustainable transportation infrastructures for societies is highly dependent on progress made in this field, and the contributions are of interest to professionals and academics involved in geotechnical and pavement engineering of roads, railways and airfields.
This book features state-of-the-art contributions in mathematical, experimental and numerical simulations in engineering sciences. The contributions in this book, which comprise twelve chapters, are organized in six sections spanning mechanical, aerospace, electrical, electronic, computer, materials, geotechnical and chemical engineering. Topics include metal micro-forming, compressible reactive flows, radio frequency circuits, barrier infrared detectors, fiber Bragg and long-period fiber gratings, semiconductor modelling, many-core architecture computers, laser processing of materials, alloy phase decomposition, nanofluids, geo-materials and rheo-kinetics. Contributors are from Europe, China, Mexico, Malaysia and Iran. The chapters feature many sophisticated approaches including Monte Carlo simulation, FLUENT and ABAQUS computational modelling, discrete element modelling and partitioned frequency-time methods. The book will be of interest to researchers and also consultants engaged in many areas of engineering simulation.
Internationally, much attention is given to causes, prevention, and rehabilitation of cracking in concrete, flexible, and composite pavements. The Sixth RILEMInternational Conference on Cracking in Pavements (Chicago, June 16-18, 2008) provided a forum for discussion of recent developments and research results.This book is a collection of papers fr
The indirect tensile test is commonly used to evaluate crack and fatigue resistance of asphalt mixtures. However, laboratory tests are time-consuming and laborious in general. Numerical simulation provides a technical way for studying the mechanical behavior of asphalt mixtures. In this research, a laboratory test and discrete element method were used to explore the effects of temperature, air void content, loading rate, and the homogeneity of a mixture on the splitting strength of asphalt mixtures. For asphalt mixtures, a three-dimensional random modeling method and two-dimensional modeling method based on X-ray computed tomography and digital image processing were developed. Also, a homogeneity evaluation index based on ring segmentation was proposed. The results show that an increase in loading rate and decrease in temperature resulted in a significant increase in splitting strength. With an increase in voids, the splitting strength of an asphalt mixture decreased. The Pearson correlation coefficient indicates that there seems to be no clear connection between splitting strength and homogeneity, but there is a significant correlation between the homogeneity and differences in the splitting strength.
Abstract : Asphalt mixture is the most widely used pavement engineering material. Because the laboratory tests of asphalt mixture are costly, researchers keep searching for a practical numerical simulation approach to facilitate their study on mixture design, compaction process, and service performance. Although the discrete element method (DEM) had been introduced into those research areas for more than three decades and has been proved to be an effective tool, its utilizing is still limited by lacking coarse aggregate morphologies, efficient modeling approaches, and complete mechanical theories. This study aims to extend the application of DEM in asphalt mixture research by 1) establishing a coarse aggregate morphology database. Coarse aggregates were categorized according to shape information and then scanned through a three-dimensional scanner. The essential morphology factors, including grain size, dimensions, surface area, volume, and specific surface area, were collected and analyzed; 2) building the gyratory compaction process. Loose material assembly was precisely generated through the developed algorithm according to the mixture design. The loose material was then compacted through the programed gyration moment. The impacts of contact parameters on compaction were investigated. Speed-up techniques were proposed and verified by analyzing the internal structure of the compacted mixtures; 3) developing a set of modeling procedures with high efficiency, low cost, reliable accuracy, and wide application. The new modeling procedures use coarse aggregate temples from the database to improve simulation accuracy and use geometry information from the gyratory compacted mixtures or random generation method to save laboratory specimens. Hexagonal close-packed (HCP) structure, which has advantages in simulating shear failure and Poisson's ratio, was employed instead of the simple cubic-centered (SCC) structure. The corresponding mechanical calculation for contact micro-parameters was then derived and verify through simple stiffness/bond tests and complete indirect tensile (IDT) tests; 4) applying DEM models to research practice. Based on those improvements, this study involved DEM in the research of the mechanical performance of asphalt mixtures with high contents of ground tire rubber (GTR). Incorporate with laboratory tests, although asphalt mixtures with high contents of GTR have lower IDT strength of was than a conventional mixture, its cracking resistance and fatigue resistance were proved to be higher. By analyzing the contact force distribution in the DEM models, rubber particles with low moduli were found to be the endogenous reason for better performance. By further investigation, the rubber particles functioned as buffers that disperse the loadings. With the above four parts of research, the application of the DEM in asphalt mixture has significant improvement in modeling techniques, mechanical theories, simulation efficiency, and scope of application.
The proliferation of technological capability, miniaturization, and demand for aerial intelligence is pushing unmanned aerial systems (UAS) into the realm of a multi-billion dollar industry. This book surveys the UAS landscape from history to future applications. It discusses commercial applications, integration into the national airspace system (NAS), System function, operational procedures, safety concerns, and a host of other relevant topics. The book is dynamic and well-illustrated with separate sections for terminology and web- based resources for further information.