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Abstract-A multiband Fractal Koch dipole textile antenna is proposed for wearable applications. The antenna is designed to operate at 0.9 GHz, 2.45 GHz and 5.8 GHz. Denim materials as the substrate are selected aiming to obtain robustness, flexibility and a lightweight textile antenna. The antenna model is designed, simulated, optimized and analyzed using Microwave Studio CST software. Two types of multiband antenna prototypes are fabricated and evaluated with different conducting elements (Shield It fabric and copper foil tape). Antenna performance is observed in terms of return loss, bandwidth, radiation pattern and realized gain. Three different comprehensive analyses are taken into consideration: measurement antenna with different bending sizes, on-body measurement and under wet conditions. The antenna performances are evaluated based on resonant frequency (f o ) and bandwidth (BW). The antennas performance with bending on the human body (arm & forearm) is compared and investigated. A suitable placement on the body has been discovered between the chest and backside. The antennas have also been tested under wet conditions to ensure a stable characteristic under the influence of water.

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Railway transport has been developed for a variety of requirements with a diversity of studies and technologies in recent years. In particular, the intercity railway transport that can be operated at speed of more than 350 km/h is the goal for the railway industry. Due to vibration and drag forces at high speed, contact force variation occurs between pantograph and catenary. This variation also causes instability in the pantograph and catenary interaction. In this study, multibody dynamics analysis is used to model the catenary. The integration of the catenary model and the pantograph model in the simulation flow produces contact force variations. A sinusoidal feed forward force and a simple feedback control force are applied to control the wave-like contact force fluctuations by means of active dampers. Evaluation of the combination of active control forces will produce optimized forces that may be able to maintain, thus improve the contact force variations.

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In recent years, high speed railway vehicle technologies have been studied and investigated in order to develop their performances with the objectives of improving riding comfort, noise reduction and high efficiency from environmental perspective. One of the essential performances is current collection stability. Operating at high speed conditions, the current collection system which consists of contact wire and pantograph suffers from contact force variation. In order to reduce such variation, pantograph design should be comprised by active control thus realizing stability. Numerical analysis can be applied to model the current collection and in particular simulate the contact force variation itself. In this study, Finite Element Method and Absolute Nodal Coordinate Formulation are used to model the wire. A free vibration experiment that focuses on the tension of wire is performed to validate the numerical models. The validated result from the experiment demonstrates the accuracy of the numerical analysis in modeling the wire. The techniques are then applied to model the contact wire for the contact force investigation. The result indicated the availability of pantograph design via simulation to achieve steady contact force.

This paper describes a newly-developed damage-based fatigue life model for the longterm reliability assessment of drawn steel wires and wire ropes. The methodology is based on the computed local stress field in the critical trellis contact zone of a stranded wire rope by FE simulations and the estimated fretting damage of the drawn wire material. A case study using a single strand (1x7) steel wire rope with 5.43 mm-dia. drawn wires is employed to demonstrate the damage-based fatigue life prediction procedures. Under applied tensile loading with peak stress corresponding to 50%MBL (P = 145 kN, R = 0.1), the von Mises stress cycles in-phase and with an identical stress ratio to the applied axial load. The damage initiation life at the trellis contact along the core wire is No = 673 cycles with an additional 589 load cycles to reach the first separation of the material point. The threshold load cycle for the fretting fatigue damage is predicted to be 12.3%MBL. An improved data set of the damage model parameters of the drawn steel wires is indispensable in achieving an accurate and validated life prediction model.

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