Felix Welsch

Universität des Saarlandes | UKS · Department of Mechatronics

Nickel-Titanium (NiTi)-based shape memory alloys (SMAs) enable new sustainable and environmentally friendly solid-state heating and cooling technologies. Elastocaloric (EC) heat pump systems exploit superelastic SMAs as a non-volatile, inflammable, and non-global-warming refrigerant, in contrast to the well-established vapor compression technology....

Shape memory alloys (SMAs) are an attractive technology in actuators and sensors because of their versatile geometry, low weight, high energy density, and low cost. Recent scientific research found that a switchable stiffness of an implant for bone fracture treatment with individual stimulation patterns to be applied to the fracture site may improv...

Shape memory alloys (SMAs) are an attractive technology in actuators and sensors because of their versatile geometry, low weight, high energy density, and low cost. The design of an SMA actuator system is generally tuned to the desired application criteria during development. Due to the thermal actuation, SMA applications are currently only conside...

Nickel-Titanium (NiTi)-based shape memory alloys (SMAs) enable new sustainable and environmentally friendly solid-state heating and cooling technologies. Elastocaloric (EC) heat pump systems exploit superelastic SMAs as a non-volatile, inflammable, and non-global-warming refrigerant, in contrast to the well-established vapor compression technology....

Cellular materials such as metal foams or auxetic metamaterials are interesting microheterogeneous materials used for lightweight construction and as energy absorbers. Their macroscopic behavior is related to their specific mesoscopic deformation by a strong structure‐property‐relationship. Digital image correlation and infrared thermography are tw...

Nonunion is a complication of long bone fractures that leads to disability, morbidity and high costs. Early detection is difficult and treatment through external stimulation and revision surgery is often a lengthy process. Therefore, alternative diagnostic and therapeutic options are currently being explored, including the use of external and inter...

Pneumatic Systems, especially those working with compressed air, come with several drawbacks like poor energy efficiency, high level of emission and limited digitalization amongst others. Therefore, there are efforts in industry to replace pneumatics with purely electrical systems. A promising approach in gripping and handling technology is the sha...

In this paper, a hybrid dynamical model for Shape Memory Alloy (SMA) wire actuators is used to develop a computationally efficient simulation framework for solid-state thermo-mechanical cooling devices. The hybrid model is grounded on a physical description of the SMA based on the Müller-Achenbach-Seelecke model, which consists of a set of ordinary...

In this paper a shape memory alloy (SMA) based handling all-in-one system is presented. The focus of this paper is the whole gripping system where several SMA based prototypes are combined in one gripping unit. The system consists of a reconfigurable SMA end-effector prototype, four bi-stable SMA actuated vacuum suction cups that are mounted on the...

Shape memory alloys (SMA) are used as an attractive technology in the field of actuators and sensors due to their versatile geometry, lightweight, high energy density, and low cost. The thermal activation principle, however, makes SMA application generally suitable for low-frequency (few Hz) regimes. In this work, a novel SMA-based antagonistic act...

In this paper, a shape memory alloy (SMA) based handling system is presented. The gripping system consists of two different actuator systems based on SMA wires. The first one is a reconfigurable end-effector with four independent gripping arms. The second SMA actuator system is a bi-stable SMA actuated vacuum suction cup, of which one is mounted on...

Elastocaloric (EC) cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required...

As an eco-friendly alternative, elastocaloric cooling promises to become an alternative to the prevalent vapor compression-based process. In the past years, many elastocaloric cooling devices have been developed. One of the most promising ones by Kirsch et al., which utilizes thin NiTiCo shape memory alloy (SMA) wires in bundle arrangements to perf...

Shape memory alloys (SMA) are used as an attractive technology in the field of actuators and sensors due to their versatile geometry, lightweight, high energy density, and low cost. The thermal activation principle, however, makes SMA application generally suitable for low-frequency (few Hz) regimes. In this work, a novel SMA-based antagonistic act...

Elastocaloric (EC) cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required...

Die Erfindung betrifft ein Verfah- ren zur Herstellung einer thermoelastischen Anordnung für einen Energiewandler, wobei thermoelastische Strangele- mente (6) mit einer konstanten Dehnung zwischen mindes- tens zwei Halteelementen (7, 7a, 7b) fixiert werden, um ein Bündel von sich in einer Längsrichtung erstreckenden Stran- gelementen (6) mit identi...

One of the most important parameters of superelastic shape memory alloys to be used in elastocaloric cooling and heating processes is their specific latent heat. Usually, the latent heat of a material is determined by differential scanning calorimetry (DSC) where the material phase transformation is induced thermally under zero stress. During elast...

One of the most important parameters of superelastic shape memory alloys to be used in elastocaloric cooling and heating processes is their specific latent heat. Usually, the latent heat of a material is determined by differential scanning calorimetry (DSC) where the material phase transformation is induced thermally under zero stress. During elast...

Festkörperkühlung ist eine umweltfreundliche Alternative zur Kältekompression oh-ne Einfluss auf den Treibhauseffekt. Elastokalorische Kühlung mittels NiTi-Formgedächtnislegierungen (FGL) weist ausgezeichnete Kühlfähigkeiten auf. Auf-grund der hohen spezifischen latenten Wärme, die bei mechanischer Be- und Ent-lastung aktiviert wird, kann eine groß...

Introduction: • Motivation • What is Elastocalorics? Basic research: • Material improvement • Process cycle investigation Elastocaloric demonstrator: • Device concept • First realization System-level simulation: • Model structure • Parameter study Possible applications Conclusion felix.welsch@imsl.uni-saarland.de

Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology without global warming potential. Due to the high specific latent heats activated by mechanical loading/unloading, large temperature changes can be generated in the material. Accompa...

Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required work...

Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required work...

Elastocaloric cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology without global warming potential. Due to the high specific latent heats activated by mechanical loading/unloading, large temperature changes can be generated in the material. Accompa...

Open-cell metal/polymer hybrid foams are biomimetic open-porous composites, consisting of a polymeric foam electrochemically coated with a metallic layer. Due to their specific pore structure, they can be used in lightweight applications or as crash absorbers. The nanocrystalline coating leads to a strengthening effect and largely improved energy a...

Die Erfindung betrifft einen thermo- elastischen Energiewandler (1), insbesondere zum Einsatz in einer thermoelastischen Heiz/Kühlvorrichtung oder in ei- nem Wärme-Kraft-Kopplungssystem, umfassend: - eine Anordnung mit mehreren Wandlereinrichtungen (3a, 3b), wobei jede der Wandlereinrichtungen (3a, 3b) in einer Erstreckungsrichtung angeordnete ein...

One of the most important parameters of superelastic shape memory alloys (SMA) to be used in elastocaloric cooling and heating processes is their specific latent heat. Thus, when developing and evaluating new materials for elastocaloric processes the determination of the latent heat is an essential step. Usually, the latent heat of a material is de...

Superelastic NiTi enables a novel environment-friendly cooling technology without global warming potential. Elastocaloric cooling uses solid stateNiTi shape memory alloys (SMA’s) as a non-volatilecooling medium compared to vapor compression-based cooling systems. In addition to being used in lightweight actuator systems and biomedical applications,...

Superelastic NiTi enables a novel environment-friendly cooling technology without global warming potential. Elastocaloric cooling uses solid state NiTi shape memory alloys (SMA’s) as a non-volatile cooling medium compared to vapor compression-based cooling systems. In addition to being used in lightweight actuator systems and biomedical application...

Superelastic NiTi enables a novel environment-friendly cooling technology without global warming potential. Elastocaloric cooling uses solid state NiTi shape memory alloys (SMA’s) as a non-volatile cooling medium compared to vapor compression-based cooling systems. In addition to being used in lightweight actuator systems and biomedical application...

Superelastic NiTi enables a novel environment-friendly cooling technology without global warming potential. Elastocaloric cooling uses solid state NiTi shape memory alloys (SMA’s) as a non-volatile cooling medium compared to vapor compression-based cooling systems. In addition to being used in lightweight actuator systems and biomedical application...

Shape memory alloys (SMA) are generally known for biocompatibility, high energy density, and self-sensing properties. In addition to being used in lightweight actuator systems and biomedical applications, these alloys exhibit excellent cooling properties. Superelastic Nickel-Titanium (NiTi) enables a novel environment-friendly cooling technology wi...

Shape memory alloys (SMA) are generally known for biocompatibility, high energy density, and self-sensing properties. In addition to being used in lightweight actuator systems and biomedical applications, these alloys exhibit excellent cooling properties. Superelastic Nickel-Titanium (NiTi) enables a novel environment-friendly cooling technology wi...

This contribution provides an experimental analysis of relevant parameters to determine the air cooling potential of elastocaloric shape memory alloys (SMAs) in the form of wires. An essential step consists in developing a scientific test setup, which offers the ability to determine these parameters under varying conditions like wire geometry, mate...

Introduction: • Elastocaloric mechanism • Cooling process • Material • Process optimization • Phase transformation kinetics 1. Novel Multi-Element Cooling Device: • Concept • Realization 2. Single element characterization: • Convective heat transfer characterization 3. Modeling: • Prediction tool for multi-wire air cooling device

The following contribution provides analyses of the air cooling potential of elastocaloric shape memory alloys (SMAs) in form of NiTiCo wires. An essential step consists in developing a scientific test setup, which offers the ability to determine the air-cooling potential under varying conditions like wire geometry, material composition, and proces...

Elastocaloric cooling based on NiTi exhibits an excellent cooling capability, due to the high specific latent heats activated by mechanical loading/unloading and the small required work input. The work of the current funding period in the DFG Priority Program SPP 1599, is focused on the development and realization of a continuous operating elastoca...

Elastocaloric cooling based on NiTi exhibits an excellent cooling capability, due to the high specific latent heats activated by mechanical loading/unloading and the small required work input. The current funding period of the DFG Priority Program SPP 1599 focuses on the development and realization of a continuously operating elastocaloric cooling...

Researche objective Motivation: • Elastocaloric cooling is: • Environment-friendly • No global warming potential • Non volatile refrigerant • Elastocaloric material provides: • Large temperature changes in material • High specific latent heats released at first-order transformation • High coefficient of performance (COP) Goal: • Development and re...

Research Topic Motivation for elastocaloric cooling:  Environment-friendly alternative to vapor compression-based systems  Large latent heats and small work input result in efficient cooling cycle  Adiabatic loading/unloading of elastocaloric material causes crystallographic phase transformation accompanied by large temperature increase/decreas...

Elastocaloric cooling based on NiTi exhibits an excellent cooling capability, due to the high specific latent heats activated by mechanical loading/unloading and the small required work input. The work of the current funding period in the DFG Priority Program SPP 1599, is focused on the development and realization of a continuous operating elastoca...

This paper presents the design and the realization of an innovative SMA actuated bistable vacuum suction cup. The sealed, compact and fully integrated design enables the positioning and transport of inherent stable components in mobile and stationary applications. The bistable actuator mechanism based on SMA wires combined with a bistable spring re...

Elastocaloric cooling is a novel environment-friendly alternative to vapor compression-based cooling systems. This solid-state cooling technology uses NiTi shape memory alloys (SMAs) as cooling medium. SMAs are well known for lightweight actuator systems and biomedical applications, but in addition, these alloys exhibit excellent cooling properties...

This poster presents the design and the realization of an innovative SMA actuated bistable vacuum suction cup.

Commercially available SMA actuated devices usually integrate only a single wire, which dimensions are determined by the force necessary to achieve a desired actuation. Usually, if higher forces are requested, a wire with a bigger diameter is chosen since bigger diameters correspond to higher forces, but, on the other hand, also to a smaller surfac...

Shape memory alloy (SMA) materials represent an attractive technology in the field of actuator mechanisms for the realization of low cost and lightweight actuators and sensors. This article presents an innovative SMA actuated bistable vacuum suction cup. The sealed, compact and fully integrated design enables the positioning and transport of differ...

Shape Memory Effect Motivation First SMA based vacuum suction cup Bistable SMA vacuum suction cup Principle Design Realization

Commercially available SMA actuated devices usually integrate only a single SMA wire. The SMA wire's dimensions are determined by the force necessary to achieve a desired actuation. Usually, if higher forces are requested, a wire with a bigger diameter is chosen since bigger diameters correspond to higher forces. On the other hand, the smaller surf...

Solid state cooling is an environment‐friendly, no global warming potential alternative to vapor compression‐based systems. Elastocaloric cooling based on NiTi shape memory alloys exhibits excellent cooling capabilities. Due to the high specific latent heats activated by mechanical loading/unloading, large temperature changes can be generated in th...

Dielectric Elastomers (DE) represent an attractive technology in the field of electromechanical transducers for the realization of low cost actuators and sensors. These devices consist of a thin DE membrane with flexible electrodes resulting in a stretchable capacitor. An electrical field, applied by the electrodes causes a thickness reduction due...

The exploitation of the elastocaloric effect in superelastic shape memory alloys (SMA) for cooling applications shows a promising energy efficiency potential but requires a better understanding of the non-homogeneous martensitic phase transformation. Temperature profiles on sputter-deposited superelastic \({\mathrm {Ti_{55.2}Ni_{29.3}Cu_{12.7}Co_{2...

The following contribution presents a new concept of an air conditioning device based on the elastocaloric cooling effect of shape memory alloys (SMA's). This technology provides an energy efficient and environment friendly alternative to conventional vapor compression based cooling principles. Starting from the thermodynamic investigation of the e...

Die Erfindung betrifft Energiewandler, die unter Nutzung von elastischer Verformung und Entspannung eines thermoelastischen Elements eine Heizwirkung bzw. eine Kühlwirkung erzielen, oder durch die Nutzung einer Temperaturdifferenz eine mechanische Energie- gewinnung ermöglicht.