Composites science and technology

Voids, the most studied type of manufacturing defects, form very often in processing of fiber-reinforced composites. Due to their considerable influence on physical and thermomechanical properties ...

https://journals.sagepub.com/doi/pdf/10.1177/0021998318772152

Voids in fiber-reinforced polymer composites: A review on their formation, characteristics, and effects on mechanical performance:

Reference EPFL-ARTICLE-184271doi:10.1016/j.compositesa.2012.08.001View record in Web of Science Record created on 2013-02-27, modified on 2017-05-10

Composites Part A: Applied Science and Manufacturing

This paper investigates comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. The methods employed comprise the use of adhesive, self-piercing rivet, bolt, clinching and welding to join only CFRP and aluminium alloys. The non-thermal joining methods received great attention though the welding process has high potential in joining these materials. Except adhesive bonding and welding, other joining methods require the penetration of metallic pins through joining parts and therefore, surface preparation is unimportant. No model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications. The choice of bonding methods depends primarily on the specific applications. The load-bearing mechanism of bolted joints is predominantly the friction that is the first stage resistance. Hybrid joints performance is enhanced by combining rivets, clinch or bolts with adhesives.

/pdf/joining-of-carbon-fibre-reinforced-polymer-cfrp-composites-b1dn74dni2.pdf

Joining of carbon fibre reinforced polymer (CFRP) composites and aluminium alloys-A review

Bistable plates for morphing structures: A refined analytical approach with high-order polynomials

Im Praktikum zur Lehrveranstaltung Simulationstechnik besteht insbesondere in der digitalen Lehre zum einen die Herausforderung der Schaffung von Voraussetzungen zur häuslichen Bearbeitung der Aufgaben. Zum anderen sind die individuellen Voraussetzungen und Fähigkeiten der Studierenden im Sinne einer nachhaltigen Lehre zu berücksichtigen. Ein Lösungsansatz hierfür ist die didaktische Methode des Flipped Classroom, bei der die Stofferarbeitung anhand von vorbereiteten Materialien wie etwa Erklärvideos in individueller Verantwortung der Studierenden liegt. Dazu wird auch die Studentenversion der Simulationssoftware Simcenter Femap genutzt, die den Studierenden am heimischen Windows-PC kostenfrei zur Verfügung steht. Die eigentliche Praktikumszeit wird in der Anwendungsphase in Form von Konsultationen und digitalen Gruppenarbeiten nach der Methode des Aktiven Plenums zur Festigung und Vertiefung der erworbenen Kenntnisse genutzt.
Diese Methode bietet eine Reihe von Vorteilen in Bezug auf die didaktischen Herausforderungen wie etwa unterschiedliche Lerntempi der Studierenden oder Aktivierung der Studierenden. Insbesondere die digitale Gruppenarbeit in Form eines Aktiven Plenums fand großen Anklang bei den Studierenden, sodass viele Elemente dieses Lehrformat auch bei der Rückkehr in verstärkte Präsenzlehre beibehalten werden.

Virtuell^2 – Simulationspraktikum im digitalen Raum

One challenge in micrometrology is to measure precisely the shape of fast moved objects with high temporal resolution.
Deformation measurements of lightweight composite materials are of importance to guarantee its robustness e.g. against
impacts. In a high-speed rotor test rig their elastic and plastic deformations due to centrifugal forces can be evaluated.
Non-contact inspection techniques with micron resolution under vacuum conditions are necessary.
For the first time, we present high-speed deformation measurements of a cylindrical rotor by a non-incremental laser
Doppler distance sensor system using fiber and diffractive optics. Besides the determination of the radial enlargement
also wobbling of the rotor was monitored.

Investigations of fast-rotating bodies using an interferometric laser Doppler distance sensor system

Characteristics of granulates used as core materials in the overmoulding process of hollow profiles

Großseriengerechte Fertigung von aktiven faserverstärkten Thermoplastverbunden

Regarding the economical use of fiber-reinforced plastics (FRP) as a construction material for structural components whose additional value caused not only in their high specific mechanical properties. Due to the layerwise structure definition of continuous fiber reinforced composites the corresponding production technologies offers a high potential for integration of additional functional elements. Past efforts to the integration of functions in fiber-reinforced composites usual provide in front of a passive use of the piezoelectric effect (eg. structural-health monitoring). Through efficient and structurally defined using of piezoceramic actuators, the planar structure topology of cylindrical hollow FRP profiles can be actively influenced. Based on experimental studies on the definition of basic concepts for the integration of thermoplastic compatible piezoceramic modules (TPM) in fiber composite tubular segments, this paper deals with the understanding and performance capabilities of such actuarical hollow frp structures. The selective excitation and manipulation of the vibration behavior of such rotationally symmetric structures serves for generation of wave effects with radial translational characteristic. The performed experimental studies on the structural behavior of active piezo integral pipe segments are abstracted and compared by means of numerical simulations using multi-physical elements.

Experimental and Numerical Studies on Integration Thermoplastic Composite Compatible Piezoelectric Ceramics for Actuatory Application of Cylindrical Hollow Structures

Maik Gude

Papers

Virtuell^2 – Simulationspraktikum im digitalen Raum

Investigations of fast-rotating bodies using an interferometric laser Doppler distance sensor system

Characteristics of granulates used as core materials in the overmoulding process of hollow profiles

Großseriengerechte Fertigung von aktiven faserverstärkten Thermoplastverbunden

Experimental and Numerical Studies on Integration Thermoplastic Composite Compatible Piezoelectric Ceramics for Actuatory Application of Cylindrical Hollow Structures