Polyester nonwoven fibrous material is widely used in construction and automobile industries for thermal insulation purposes. It is worthy and meaningful to understand the effect of structural parameters on the thermal property. Fiber orientation, as one of the most vital parameters, has a significant effect on thermal property. However, there has been little quantitative analysis focusing on this aspect. This paper theoretically and experimentally analyzes the thermal conductivity of samples with varying fiber orientation. Existing models were selected to predict the thermal conductivity of polyester nonwoven samples. Two different apparatus were applied to carry out the experimental measurements. The relative differences between the predicted and measured results were compared. One commonly used model was modified for accurate prediction. It was shown that some existing models under- or overestimate the thermal conductivity compared to the measured values. The results indicate that the modified model can accurately predict the thermal conductivity of polyester nonwoven materials within a 0.2% relative difference.

Bamboo is a remarkably strong and sustainable material available for construction. It exhibits optimized mechanical characteristics based on a hollow-inhomogeneous structure which also affects its fracture behavior. In this study, the aim is to investigate the effect of material composition and geometrical attributes on the fracture mechanisms of bamboo in various modes of loading by the finite element method. In the first part of the investigation, the optimized transverse isotropy of bamboo to resist transverse deformation was numerically determined to represent its noticeable orthotropic characteristics which prevail in the axial direction. In the second part of this study, a numerical investigation of fracture mechanisms in four fundamental modes of loading, namely bending, compression, torsion, and shear, were conducted by considering the failure criterion of maximum principal strain. A crack initiation stage was simulated and compared by implementing an element erosion technique. Results showed that the characteristics of bamboo’s crack initiation differed greatly from solid geometry and homogeneous material-type models. Splitting patterns, which were discerned in bending and shear modes, differed in terms of location and occurred in the outside-center position and inside-lowermost position of the culm, respectively. The results of this study can be useful in order to achieve optimized strength in bamboo-inspired bionic designs.

Macroscopic deformation characteristics of plain weave structure, the most basic woven fabric, are significantly influenced by its mesoscale shape and internal stress state, depending on weaving process factors. This study analyses numerically the effects of the design variables, i.e. the wire pitch on the heddle/shuttle and the plasticity of the metal wires of plain weave, on the deflection state of the warp and weft wires. A model with continuity of the weave structure simulates the simple weaving process using the finite element method in anticipation of its application to homogenisation methods. Furthermore, the continuous curvature between contact points is analysed mathematically to evaluate the finished shape in plain woven structures. Considering internal stress by the weaving process and elastoplasticity of metal wires, the deflection curve is closer to straight lines than the ideal deflection curve in elasticity, owing to local yielding and tension caused by the plasticity effect and setting, respectively.

The tactile sensation of towel fabrics, which originates from their pile structure, is strongly affected by the mechanical response under the low loads applied at the instant of contact. The pile structures formed from spun yarns create a graded surface with extremely low elasticity at the outermost layer, complicating the quantitative assessment of tactile properties. This study proposed a quantitative framework for evaluating the tactile performance of ultra-soft textiles using low-load indentation testing and finite element analysis (FEA). Mechanical responses of towel samples were measured through controlled indentation and incorporated into an FEA model simulating skin contact. Stress-based indices-including pressure, principal stresses, Tresca stress, and von Mises stress-were calculated to characterize mechanical stimuli applied to the skin. Correlations between these indices and the initial elastic modulus of the pile structure were examined to identify parameters reliably representing tactile performance. The results show that Tresca and von Mises stresses exhibit strong linear relationships with the structural modulus even under low-stress conditions, highlighting their potential as objective design metrics for developing textiles with targeted tactile qualities. This framework provides a systematic approach for quantitatively linking fabric microstructure to perceived tactile behavior, facilitating design optimization of ultra-soft materials.