Digital twin applications in 3D concrete printing

The benefits of 3D concrete printing (3DCP) include reducing construction time and costs, providing design freedom, and being environmentally friendly. This technology is expected to be effective in addressing the global house shortage. This review highlights the main 3DCP applications and four critical challenges. It is proposed to combine 3D concrete printing with Digital Twin (DT) technology to meet the challenges the 3DCP faces and improve quality and sustainability. This paper provides a critical review of research into the application of DT technology in 3DCP, categorize the applications and directions proposed according to different lifecycles, and explore the possibility of incorporating them into existing 3DCP systems. A comprehensive roadmap was proposed to detail how DT can be used at different lifecycle stages to optimize and address the four main challenges of 3DCP, providing directions and ideas for further research

Environmentally Friendly Smart Construction—Review of Recent Developments and Opportunities

Modern economic, social and environmental challenges require a new type of construction that ensures resilience, low construction costs and ease of maintenance. Material production, manufacturing of structural elements and final assembly should minimise the environmental impacts, such as greenhouse emissions and waste production. This review aims to identify the key routes of research and development required to address the environmental challenges the construction industry faces. It outlines recent advances and highlights the rising opportunities. The strategies with great perspectives include 3D concrete printing, prefabrication and modular construction, mortarless construction, development and utilization of sustainable, smart and composite materials, renewable energy systems and automation technologies including the Digital Twin technology. Hybrid approaches that combine traditional and novel construction methods present the greatest potential. Overall, collaboration between stakeholders is crucial in driving innovation and successfully implementing these advancements

Negative Stiffness, Incompressibility, and Strain Localisation in Particulate Materials

In this paper, we consider two mechanisms capable of inducing strain localisation in particulate geomaterials in compression: the apparent negative stiffness and the incremental incompressibility caused by dilatancy. It is demonstrated that the apparent negative stiffness can be produced by the rotation of clusters of particles in the presence of compression. The clusters are formed by connecting the particles by the bonds that still remain intact in the process of bond breakage in compression. We developed a 2D isotropic model of incremental incompressibility showing that a single strain localisation zone is formed inclined at 45° to the direction of axial compressive loading. This mechanism of localisation was analysed through Particle Flow Code (PFC) 2D and 3D simulations. It is shown that, in the simulations, the peak stress (the onset of localisation) does correspond to the incremental Poisson’s ratio, reaching the critical values of 1 (in 2D) and 0.5 (in 3D)

Planar isotropic structures with negative Poisson’s ratio

AbstractA new design principle is suggested for constructing auxetic structures – the structures that exhibit negative Poisson’s ratio (NPR) at macroscopic level. We propose 2D assemblies of identical units made of a flexible frame with a sufficiently rigid reinforcing core at the centre. The core increases the frame resistance to the tangential movement thus ensuring high shear stiffness, whereas the normal stiffness is low being controlled by the local bending response of the frame. The structures considered have hexagonal symmetry, which delivers macroscopically isotropic elastic properties in the plane perpendicular to the axis of the symmetry. We determine the macroscopic Poisson’s ratio as a ratio of corresponding relative displacements computed using the direct microstructural approach. It is demonstrated that the proposed design can produce a macroscopically isotropic system with NPR close to the lower bound of −1. We also developed a 2D elastic Cosserat continuum model, which represents the microstructure as a regular assembly of rigid particles connected by elastic springs. The comparison of values of NPRs computed using both structural models and the continuum approach shows that the continuum model gives a healthy balance between the simplicity and accuracy and can be used as a simple tool for design of auxetics

11th International Workshop on Bifurcation and Degradation in Geomaterials dedicated to Hans Muhlhaus

This book contains the scientific contributions to the 11th International Workshop on Bifurcation and Degradation in Geomaterials (IWBDG) held in Limassol-Cyprus, May 21-25, 2017. The IWBDG series have grown in size and scope, since their inception 30 years ago in Germany, covering more and wider areas of geomaterials and geomechanics research including modern trends. The papers cover a wide range of topics including advances in instabilities, localized and diffuse failure, micromechanical, multiscale phenomena, multiphysics modeling and other related topics. This volume gathers a series of manuscript by brilliant international scholars who work on modern recent advances in experimental, theoretical and numerical methods. The theoretical and applied mechanics are linked successfully with engineering applications in traditional and in emerging fields, such as geomechanics for the energy and the environment. The quality of the contributed papers has benefited from the peer review process by expert referees. This book can be used as a useful reference for research students, academics and practicing engineers who are interested in the instability and degradation problems in geomaterials, geomechanics, geotechnical engineering and other related applications