Concurrent geometrico-topological tuning of nanoengineered auxetic lattices fabricated by material extrusion for enhancing multifunctionality: multiscale experiments, finite element modeling and data-driven prediction

This study demonstrates the multifunctional performance of innovative 2D auxetic lattices through a combination of multiscale experiments, finite element modeling and data-driven prediction. A geometric modeling approach utilizing Voronoi partitioning and a unique branch-stem-branch (BSB) structure, patterned according to 2D wallpaper symmetries, enables precise concurrent geometric and topological tuning of lattices across a continuous parameter space. Selected architectures are physically realized via material extrusion of polylactic acid (PLA) infused with carbon black (CB). Experimental characterizations, supported by Finite Element modeling, reveal the significant influence of BSB structure's design parameters on mechanical and piezoresistive performance under tensile loading, with a remarkable Poisson’s ratio of -0.74, accompanied by a 15-fold increase in elastic stiffness and a 34-fold increase in strain sensitivity. Additionally, architecturally, and topologically tailored lattice structures exhibit tunable damage sensitivity, reflecting the rate of conductive network destruction within the lattice. This offers insights into the rapidity of cell wall failure, with a steeper slope of the piezoresistance curve in the inelastic regime indicating a faster breakdown and quicker onset of mechanical failure. Integration of Gaussian Process Regression enables accurate exploration of the design space beyond realized structures, highlighting the potential of these intelligent lattice structures for applications such as sensors and in situ health monitoring, marking a significant advancement in multifunctional materials

Dissecting Driver Behaviors Under Cognitive, Emotional, Sensorimotor, and Mixed Stressors

In a simulation experiment we studied the effects of cognitive, emotional, sensorimotor, and mixed stressors on driver arousal and performance with respect to (wrt) baseline. In a sample of n = 59 drivers, balanced in terms of age and gender, we found that all stressors incurred significant increases in mean sympathetic arousal accompanied by significant increases in mean absolute steering. The latter, translated to significantly larger range of lane departures only in the case of sensorimotor and mixed stressors, indicating more dangerous driving wrt baseline. In the case of cognitive or emotional stressors, often a smaller range of lane departures was observed, indicating safer driving wrt baseline. This paradox suggests an effective coping mechanism at work, which compensates erroneous reactions precipitated by cognitive or emotional conflict. This mechanisms’ grip slips, however, when the feedback loop is intermittently severed by sensorimotor distractions. Interestingly, mixed stressors did not affect crash rates in startling events, suggesting that the coping mechanism’s compensation time scale is above the range of neurophysiological latency

Practical Image Based Lighting

In this paper, we present a user-friendly and practical method for seamless integration of computergeneratedimages (CG) with real photographs and video. In general, such seamless integration isextremely difficult and requires recovery of real-world information to simulate the same environment forboth CG and real objects. This real-world information includes camera positions and parameters,shapes, material properties, and motion of real objects. Among these, one of the most important islighting.Image-based lighting that is developed to recover illumination information of the real world fromphotographs has recently become popular in computer graphics. In this paper we present a practicalimage-based lighting method that is based on a simple and easily constructable device: a square platewith a cylindrical stick. We have developed a user-guided system to approximately recover illuminationinformation (i.e. orientations, colors, and intensities of light sources) from a photograph of this device.Our approach also helps to recover surface colors of real objects based on reconstructed lightinginformation

Intuitive and Effective Design of Periodic Symmetric Tiles

This paper presents a new approach for intuitive and effective design of periodic symmetric tiles. We observe that planar graphs can effectively represent symmetric tiles and graph drawing provides an intuitive paradigm for designing symmetric tiles. Moreover, based on our theoretical work to represent hexagonal symmetry by rectangular symmetry, we are able to present all symmetric tiles as graphs embedded on a torus and based on simple modulo operations. This approach enables us to develop a simple and efficient algorithm, which has been implemented in Java. By using this software, designers, architects and artists can create interesting symmetric tiles directly on the web. We also have designed a few examples of symmetric tiles to show the effectiveness of the approach

An Interactive Shape Modeling System for Robust Design of Functional 3D Shapes

In Architecture, it is essential to design functional and topologically complicated 3D shapes (i.e. shapes with many holes, columns and handles). In this paper, we present a robust and interactive system for the design of functional and topologically complicated 3D shapes. Users of our system can easily change topology (i.e. they can create and delete holes and handles, connect and disconnect surfaces). Our system also provide smoothing operations (subdivision schemes) to create smooth surfaces. Moreover, the system provides automatic texture mapping during topology and smoothing operations. We also present new design approaches with the new modelling system. The new design approaches include blending surfaces, construction of crusts and opening holes on these crusts

Interactive Rind Modeling for Architectural Design

The paper presents a new modeling technique for architectural design. Rind modeling provides for the easy creation of surfaces resembling peeled and punctured rinds. We show how the method's two main steps of 1) creation of a shell or crust and then 2) opening holes in the crust by punching or peeling can be encapsulated into a real time semi-automatic interactive algorithm.The rind modeling method allows us to develop a user-friendly tool for designers and architects. The new tool extends the abilities of polygonal modeling and allows designers to work on structured and consistent models for architectural design purposes. Rind modeling gives architects and designers a processing flexibility. It can be used in conceptual modeling during the early design phase. It can also be efficiently used for creating variety of shell structures for architectural design