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Immersed isogeometric analysis with boundary conformal quadrature for finite deformation elasticity
No full textNumerical simulation of complex geometries can be an expensive and time-consuming undertaking, in particular due to the lengthy preparation of geometry for meshing and the meshing process itself. To tackle this problem, immersed boundary and fictitious domain methods rely on embedding the physical domain into a Cartesian grid of finite elements and resolving the geometry only by adaptive numerical integration schemes. However, the accuracy, robustness, and efficiency of immersed or cut cell approaches depends crucially on the integration technique applied on trimmed cells. This issue becomes more apparent in nonlinear problems, where intermediate solution steps are necessary to achieve convergence. In this work, we adopt an innovative algorithm for boundary conformal quadrature that relies on a high-order B-spline re-parameterization of trimmed elements to address small and large deformation elasticity problems. We accomplish this using spline-based immersed isogeometric analysis, which eliminates the need for body conformal finite element mesh. The integration points are obtained by applying classical Gauss quadrature to conformal re-parameterizations of the cut elements, whereas the discretization itself is not refined. This ensures a precise integration with minimum quadrature points and degrees of freedom. The proposed immersed isogeometric analysis with boundary conformal quadrature is evaluated on benchmark problems for 2D linear and nonlinear elasticity. The results show convergence with optimal rates in h -and k -refinement, thus demonstrating the efficiency and the precision of the method. As demonstrated, in conjunction with the simple to implement penalization and deformation map resetting approaches in the fictitious domain, it performs robustly also for finite deformations. Furthermore, it is exemplified that the method can be easily applied for multiscale homogenization of microstructured materials in the large deformation regime
Solid-state polycyclotrimerization of diynes to porous organic polymers
No full textHerein, we report a solid-state polycyclotrimerization of 1,4-diethynylbenzene using mechanochemical activation in a ball mill, yielding a highly porous and hydrophobic hyperbranched polymer (HBP) with a specific surface area of up to 570 m² g⁻¹. The reaction, catalyzed by Fe(hmds)2 and conducted under solvent-free conditions, was optimized by varying milling time and frequency. This method enables the efficient synthesis of insoluble, porous organic polymers with high yields (up to 95%) and offers an environmentally friendly alternative to traditional solution-based polymerizations
Development of Deep Biomimetic Quadruped Robot with Bow-string Structure in Cursorial Mammals
No full textThe flexible trunk of quadrupedal mammals plays an essential role in achieving agile movements. The mammalian trunk, segmented into the cervical, thoracic, lumbar, sacral, and caudal vertebrae, allows sagittal bending for high-speed running, axial rotation for balance, and lateral bending for turning. While the trunk achieves flexibility, it must also provide sufficient stiffness for weight-bearing. To extract design principles for a flexible trunk in agile robots, this study develops a "deep'' biomimetic quadruped robot that mimics both the macroscopic weight-bearing structure, i.e., the bow-string structure, and the deep-layered structure of the abdominal wall. The developed robot demonstrated that the proposed trunk design can implement flexibility in the roll, pitch, and yaw axes, as well as the ability to bear the body weight during walking
Contrast Optimization for Camera-Based ADAS to Enhance Object Visibility Using Pixel Light Technology
No full textMicro-LED pixel emitter arrays mark an important advancement in automotive lighting technology. Their exceptional resolution by means of high pixel counts enables precise and adaptive beam shaping, making them ideal for real-time optimization under varying traffic and environmental conditions. This functionality significantly enhances the capabilities of Adaptive Driving Beam (ADB) headlamps, allowing for glare-free high beams and improved safety. Moreover, their energy-efficient selective activation supports more sustainable lighting designs, and their potential to project images or symbols adds further value in terms of road communication. To fully leverage the benefits of pixel lighting technology, it is essential to understand how resolution, and pixel activation strategies influence visual contrast and object visibility. This work presents a physically based, large-scale simulation approach that systematically varies pixel densities and scene parameters such as distance, ambient luminance, and object reflectance. Over two billion combinations were analyzed to evaluate object detectability. Results reveal a strong non-linear relationship between pixel resolution and visibility performance. Visibility improves rapidly up to ~100,000 pixels, then saturates between 150,000-200,000 pixels, indicating a practical resolution threshold. Key influencing factors include object distance, pixel density, reflectance, and activation logic. These findings support a shift in headlamp design: from maximizing brightness to optimizing contrast through intelligent and resolution-aware light distribution. The presented framework offers a basis for future ADAS-oriented lighting development
Uncertainty-Awareness in AI-Augmented Decision-Making: Explaining Appropriate Reliance through Cognitive Mechanisms
No full textAn approach for reconstructing dinosaur locomotion using physical skeletal platforms
No full textIn this paper, we introduced an approach to reconstructing dinosaur locomotion using physical skeletal platforms based on skeletal specimens of dinosaurs and their extant relatives. Following this approach, we identified the stance mechanism of the crocodilian hindlimb and implemented it to the dinosaur skeletal platform. As a result, we successfully reconstructed the stance of dinosaurs
Neural Control for Soft Robot Terrestrial-Aquatic Locomotion
No full textSoft robots exhibit notable adaptability through passive morphological computation; however, they often lack the ability to actively predict and respond to environmental changes. This study presents a hybrid strategy combining passive adaptation and active adaptation via neural computation. The neural computation employs a central pattern generator (CPG)-based control for locomotion and a neural reservoir computing (RC)-based model for sensory prediction. This model enables the robot to estimate its state and detect disturbance using prediction errors, which adjust control parameters in response to environmental shifts. Experimental results demonstrate this approach's effectiveness in a soft crawling robot during terrestrial-aquatic transitions, highlighting the benefits of active adaptation for locomotion resilience
The Relationship of Psychological and Behavioural Factors and Prosthesis Satisfaction in Daily Life: A Pilot Case Study
No full textUsing Ecological Momentary Assessment (EMA), this study examined daily fluctuations in prosthesis satisfaction and psychological factors in a lower-limb amputee, highlighting the role of real-time assessment in understanding user experience
Vorträge zum 9. Darmstädter Geotechnik-Kolloquiums am 14. März 2002
No full textMit dem Mitteilungsheft Nr. 58 publizieren das Institut und die Versuchsanstalt für
Geotechnik der Technischen Universität Darmstadt die Beiträge zum 9. Darmstädter
Geotechnik-Kolloquium mit den folgenden Themenschwerpunkten:
- Umweltgeotechnik
- Abdichtungssysteme im Tunnel- und Tiefbau
- Langzeiterfahrungen I Modellbildungen
- Rechtsfragen in der Geotechnik I Schadensfäll
Einfluß der Kapillarität auf die Mehrphasenströmung bei der Sanierung von Mineralölschadensfällen im Boden
No full textMit dem Mitteilungsheft Nr. 45 publizieren das Institut und die Versuchsanstalt für Geotechnik der Technischen Universität Darmstadt die wissenschaftliche Arbeit von Herrn Dr.-Ing. Matthias Vogler, der sich den hochinteressanten und hochaktuellen Themengebieten Kapillarität und Mehrphasenströmung widmet und den herausragenden Stellenwert der Kapillaritätseffekte auf die Durchführung und Bewertung der Sanierung von Mineralölschadenfällen aufzeigt