Omar Ben Dali

Omar Ben Dali
Technische Universität Darmstadt | TU · Department of Electrical Engineering and Information Technology (Dept.18)

Master of Science

About

11
Publications
2,604
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72
Citations

Publications

Publications (11)
Article
Laser-based powder bed fusion as an additive manufacturing process allows the integration of sensors at any location within the manufactured part. This allows for manufacturing smart parts that can be integrated into complex structures for monitoring applications, as they can perform in-situ measurements. Especially, monitoring of force and torque...
Conference Paper
Full-text available
Ferroelectrets are piezoelectric polymers, typically cellular polymer foams that exhibit a large piezoelectric response. In this work, we present a biodegradable 3D printed ferroelectret using Fused Deposition Modeling (FDM). Even though the charging process of the ferroelectret is conducted at room temperature, the printed PLA exhibits good charge...
Article
Full-text available
Piezoelectrets are artificial ferroelectrics that are produced from non-polar air-filled porous polymers by symmetry breaking through high-voltage-induced Paschen breakdown in air. A new strategy for three-layer polymer sandwiches is introduced by separating the electrical from the mechanical response. A 3D-printed grid of periodically spaced therm...
Conference Paper
Full-text available
Ferroelectrets are typical cellular polymer foams that exhibit high flexibility and an excellent matching to air. Recently, biodegradable cellular polylactic acid (PLA) ferroelectrets have been introduced, exhibiting a large longitudinal piezoelectric coefficient. In this work, we present a combination of a PLA film and a printed PLA backplate usin...
Article
Full-text available
Vibrational energy harvesters of air-spaced cantilever design, utilizing ferroelectrets as the electroactive element, are a very recent concept. Such systems, based on the d 31 piezoelectric effect are further studied with harvesters of improved design, partially implemented by additive manufacturing. The focus of the present work is on the depende...
Article
Fluorinated polyethylene propylene (FEP) ferroelectrets with an air-filled parallel-tunnel structure and regularly distributed bipolar space charges can stimulate integration of ferroelectrets in transducers due to their unique piezoelectric and mechanical properties. Such FEP ferroelectret films exhibit not only large longitudinal piezoelectric ac...
Article
Full-text available
Polymers with electrically charged internal air cavities (ferroelectrets) reveal a pronounced piezoelectric response and are regarded as soft electroactive multi-functional materials. This work presents preliminary results on the preparation and piezoelectric effect of ferroelectrets based on the polylactic acid (PLA) polymer. A distinctive feature...
Article
Full-text available
We present a vibrational energy harvester with fluorinated ethylene propylene (FEP)-ferroelectrets working in d31 mode. The ferroelectret film consists of two FEP films, fused together to form a parallel tunnel structure with well-defined air gaps. Its dynamic piezoelectric g31 coefficient is 0.7 V m N−1. The energy-harvesting device is an air-spac...
Article
Full-text available
Energy harvesting from vibrations provides power to low‐energy consuming electronics for stand‐alone and wearable devices as well as for wireless and remote sensing. In this contribution, compact tubular ferroelectret energy harvesters utilizing a single‐tube design are presented. Such single‐tube harvesters can be fabricated from commercially avai...
Conference Paper
We present a simulation of an ultrasonic transducer element with piezoelectric and electrostatic transduction combined and with two bending plates. It combines the high SPL of a piezoelectric transducer with the tunable resonance frequency of a CMUT due to spring softening effect. In this work, we compare two state-of-the-art transducers with our a...

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Projects

Project (1)
Project
Investigation of piezoelectret energy harvesting systems using the piezoelectric transverse effect, such as cantilever beams and diaphragms.