Topological Design of Strain Sensing Nanocomposites

High-performance piezoresistive nanocomposites have attracted extensive attention because of their significant potential as next-generation sensing devices for a broad range of applications, such as monitoring structural integrity and human performance. While various piezoresistive nanocomposites have been successfully developed using different material compositions and manufacturing techniques, current development procedures typically involve empirical trial and error that can be laborious, inefficient, and, most importantly, unpredictable. Therefore, this paper aims to propose and validate a topological design-based methodology to strategically manipulate the piezoresistive effect of nanocomposites to achieve a wide range of optimized strain sensitivities without changing the material system. In particular, this work designed patterned nanocomposite thin films with stress-concentrating and stress-releasing topologies. The strain sensing properties of the different topology nanocomposites were characterized and compared via electromechanical experiments. Those results were compared to both linear and nonlinear piezoresistive material model numerical simulations. Both the experimental and computational results indicated that the stress-concentrating topologies could enhance strain sensitivity, whereas the stress-releasing topologies could significantly suppress bulk film piezoresistivity.

LOAD CAPACITY OF HELICOIL® INSERTS IN ABS M30 MATERIAL USED FOR ADDITIVE MANUFACTURING

This paper deals with experimental investigations and numerical simulations of HELICOIL® inserts in ABS-M30 plastic. The aim is to explore the possibilities of modelling HELICOIL® inserts using Finite Element Method (FEM) and thus predict the load-bearing capacity of these inserts. The motivation was based on a previously published article that dealt with the topological design of the robot manipulator arm shape. During the mechanical tests, the structure of the arm did not collapse, but the HELICOIL® inserts were torn out. To determine the load-bearing capacity of HELICOIL® inserts, the necessary experimental tests were designed and carried out. FEM calculations of the inserts were adjusted to the obtained data. The results from the FEM were verified in an experimental validation test.

Forced unfolding of protein-inspired single-chain random heteropolymers

Synthetic random heteropolymers (RHPs) with high chemical heterogeneity can self-assemble into single-chain nanoparticles that exhibit features reminiscent of natural proteins, such as topological polymorphism. Using all-atom molecular dynamics simulations, this work investigates the structure and single-chain mechanical unfolding of a library of four-component RHPs in water, studying the effects of sequence, composition, configuration, and molecular weight. Results show that compactified RHPs can have highly dynamic unfolding behaviors which are dominated by complex side-chain interactions and prove markedly different from their homopolymer counterparts. For a given sequence and conformation, an RHP’s backbone topology can strongly impact its unfolding response, hinting at the importance of topological design in the nanoscale mechanics of heteropolymers. In addition, we identify enthalpically-driven reconfiguration upon unfolding, observing a solvent-shielding protection mechanism similar to protein stabilization by PEGylation. This work provides the first computational evidence for the force-induced unfolding of protein-inspired multicomponent heteropolymers.

Topological Design of Multi-Material Compliant Mechanisms with Global Stress Constraints

This paper presents an approach for the topological design of multi-material compliant mechanisms with global stress constraints. The element stacking method and the separable stress interpolation scheme are applied to calculate the element stiffness and element stress of multi-material structures. The output displacement of multi-material compliant mechanisms is maximized under the constraints of the maximum stress and the structural volume of each material. The modified P-norm method is applied to aggregate the local von Mises stress constraints for all the finite elements to a global stress constraint. The sensitivities are calculated by the adjoint method, and the method of moving asymptotes is utilized to update the optimization problem. Several numerical examples are presented to demonstrate the effectiveness of the proposed method. The appearance of the de facto hinges in the optimal mechanisms can be suppressed effectively by using the topology optimization model with global stress constraints, and the stress constraints for each material can be met.

The application of topological geometry to the architectural concept design process in the flow of digitalization

PurposeThe paper aims to research the applications of topological geometry to the architectural concept design process and their combination with the modern digital technology to find novel architectural spaces and forms which are dynamic, easily adaptable to the context and surroundings.Design/methodology/approachThe article uses the method of studying the existing literature on topological geometry and architectural design theory including design thinking, architectural design methods and architectural compositions to analyze and compare them with architectural practices and suggest new topological design tools and methods. Moreover, the paper tests the proposals with a number of preliminary design research experiments. In addition, graphic design software, parametric design, building information modeling (BIM) and digital development trends in architecture were explored and experienced to reveal the application potential of topological design thinking and methods in the trend of architectural digitization.FindingsThe paper has analyzed, synthesized and systematized the basic theories of topological geometry in order to clarify their applications in the architectural concept design process. On that basis, the paper proposes a novel topological design thinking and method for finding rich diversified architectural ideas and forms based on original invariant design constraints. Finally, the paper clarifies the combination as well as the mutual, motivating relationship between topological geometry and modern digital technologies when applied to architectural design.Originality/valueThe research contributes a novel design thinking and method based on topological geometry combined with modern digital technology to the architectural design theory. It will be a valuable tool capable of suggesting architects how to think and innovate in architecture in the era of industrial revolution 4.0.