Modeling Cylindrical Inhomogeneity of Finite Length with Steigmann–Ogden Interface

A mathematical model employing the concept of energy-equivalent inhomogeneity is applied to analyze short cylindrical fiber composites with interfaces described by the Steigmann–Ogden material surface model. Real inhomogeneity consists of a cylindrical fiber of finite length, and its surface possessing different properties is replaced by a homogeneous, energy-equivalent cylinder. The properties of the energy-equivalent fiber, incorporating properties of the original fiber and its interface, are determined on the basis of Hill’s energy equivalence principle. Closed-form expressions for components of the stiffness tensor of equivalent fiber have been developed and, in the limit, shown to compare well with the results available in the literature for infinite fibers with the Steigmann–Ogden interface model. Dependence of those components on the radius, length of the cylindrical fiber, and surface parameters is included in these expressions. The effective stiffness tensor of the short-fiber composites with so-defined equivalent cylindrical fibers can be determined by any homogenization method developed without accounting for interface.

Effect of Fiber Angle Variation on Bending Behavior of Semi-Cylindrical Fiber-Reinforced Soft Actuator

Soft robots are a specific type of robots that are made of elastomeric materials. A specific type of soft actuators (soft robots) are called fiber-reinforced soft actuators. Effective parameters in the motion of fiber-reinforced soft actuators are cross-section area, thickness of the actuator, number of threads wrapped around the actuator, angle of threads, and if the fiber is wrapped one-way or two-way. Some of these parameters are already studied by researchers in the field. In this research, the aim is to investigate the effect of the angle of the fiber on the motion of a semi-cylindrical fiber-reinforced soft actuator with an inextensible layer attached to its flat surface. This paper studies the behavior analysis of the actuator, which is modeled in a finite element software. The behavior of the actuator in terms of bending is then studied by changing the angle of the fiber wrapped around the outer surface of the actuator. Results show that the bending behavior of the actuator highly depends on the fiber angle. Simulation results are then validated with experiment. The results presented in this paper provides an instruction on how one can improve or optimize the bending workspace of the actuator as needed.

Study on the Single Scattering of Elastic Waves by a Cylindrical Fiber with a Partially Imperfect Bonding Using the Collocation Point Method

The single scattering of P- and SV-waves by a cylindrical fiber with a partially imperfect bonding to the surrounding matrix is investigated, which benefits the characterization of the behavior of elastic waves in composite materials. The imperfect interface is modelled by the spring model. To solve the corresponding single scattering problem, a collocation point (CP) method is introduced. Based on this method, influence of various aspects of the imperfect interface on the scattering of P- and SV-waves is studied. Results indicate that (i) the total scattering cross section (SCS) is almost symmetric about the axis α=π/2 with respect to the location (α) of the imperfect interface, (ii) imperfect interfaces located at α=0 and α=π highly reduce the total SCS under a P-wave incidence and imperfect interfaces located at α=π/2 reduce the total SCS most significantly under SV-incidence, and (iii) under a P-wave incidence the SCS has a high sensitivity to the bonding level of imperfect interfaces when α is small, while it becomes more sensitive to the bonding level when α is larger under SV-wave incidence.

Effective enhancement of the mechanical properties of macroscopic single-walled carbon nanotube fibers by pressure treatment

A SWNTs cylindrical fiber is fabricated with diamond wire drawing dies and the SWNT ribbon-like fiber is obtained by pressure treatment. The tensile strength and Young's modulus of ribbon-like fibers can be enhanced with a maximum factor about 55.