Damping of two deformation modes by one control loop has been demonstrated by simulation for a typcial 3 MW wind turbine. The vibration levels of the 2 and 3 in-plane modal modes were significantly reduced. Calculations with the aerodynamic code PHATAS showed an overall in-plane fatigue load reduction by ca 40%. The control loop includes a Kalman filter that estimates state variables for the mo...

Finite element analysis methods have been used to calculate the effects of trimming bridges on the first several frequencies of vibration. Violin bridges and both standard and Belgian designs of cello bridges have been investigated. Calculations of both in-plane and out-of-plane vibrating modes have been made when the feet were rigidly fixed. In one case, no motion out-of-plane was permitted. I...

To evaluate the effect of short-duration, high-load resistive exercise, with and without whole body vibration on lumbar muscle size, intervertebral disk and spinal morphology changes, and low back pain (LBP) incidence during prolonged bed rest, 24 subjects underwent 60 days of head-down tilt bed rest and performed either resistive vibration exercise (n = 7), resistive exercise only (n = 8), or ...

This paper presents a simple analytical method to optimize the efficiency of two types of electrostatic Vibration Energy Harvesters (VEH): the out-of-plane (OPGC) and in-plane (IPGC) gap-closing converters. The electrical and mechanical behaviours of the transducer are addressed simultaneously, while a voltage limitation on the transducer’s terminals is set to prevent any damage in the conditio...

This paper reports a microfabricated piezoelectric MEMS inertial energy harvester that can scavenge high-frequency mechanical vibrations in all three dimensions with an active inner volume of only 55 mm. The device can generate 0.1 to 10.5 μW from out-of-plane vibrations (365-465 Hz), and 0.1 to 3.2 μW from in-plane vibrations (680-930 Hz) at 0.5 g acceleration input. The reported harvester is ...

We propose a new lateral force feedback device, the UltraShiver, which employs a combination of in-plane ultrasonic oscillation (around 30 kHz) and out-of-plane electroadhesion. It can achieve a strong active lateral force (400 mN) on the bare fingertip while operating silently. The lateral force is a function of pressing force, lateral vibration velocity, and electroadhesive voltage, as well a...

background and aims: whole body vibration (wbv) transmitted to drivers is one of the main reasons for several different symptoms such as musculoskeletal disorders. one of the recommendations to decrease the effects of whole body vibration is using a device that acts as an isolator. in this study, we used an air cushion as a device to decrease wbv. we measured whole body vibration transmitted to...

Assumption of cutting disturbances in hard turning process (caused by variations in depth of cutting, high passive force Fp or small tool nose radius) could be confirmed with several indicators. These indicators can be monitored during turning process(forces, vibrations, sound, etc.) or after process has been finished (roughness, temperature, wear, etc). Variation of depth of cutting as well as...

Part with sculptured surfaces is obtained in three stages: roughing, semi-finishing and finishing. The roughing operation consists in using flat end tools or fillet end tools on sequential horizontal cutting planes to remove the most material from the raw part as rapidly as possible using “Parallel Planes” or “Offset Contours” machining strategy. When roughing deep parts, radial cutting forces,...