DESIGN OF NOVEL MICRO-PUMPS FOR MECHATRONIC APPLICATIONS

Abstract Due to the rapid development and increasing usage of micro fluid instruments in recent years, their fabrication has attracted a lot of attention recently. Micro -pumps are one of the sub branches of electro-mechanics along with the non-return valves or nozzle/ diffuser elements. Because of the problems arising with non-return valves such as blocking, erosion, failure of moving parts and etc., researchers incline towards the micro-pumps with nozzle/diffuser elements which are more reliable due to the simplicity and maintenance free characteristics. The main target in this paper is to modify the design of micro-pumps in such a way to increase the net flow rates while decreasing the fabrication cost. There are mainly three micro-pumps considered. One of them is the reference micro-pump which has a single chamber, an actuated by piezoelectric, an inlet (Nozzle) and outlet (Diffuser) elements. The second one is designed by modifying the internal space of the chamber by combining t he rectangular and elliptical shapes together, which is hereby, named arched chamber Micro-pump. The third one is modelled in which two reference chambers are in parallel with a single piezo -electric actuator located at the interface. In the simulation carried out, the basic elements of reference, arched chamber, and parallel micro-pumps are modelled in equivalent conditions for easy comparing. The result shows a major improvement in arched micro-pump with respect to net flow rates, by decreasing back pressure value and eddy currents

INVESTIGATION OF ELECTRO-MECHANICAL FACTORS EFFECTING PIEZOELECTRIC ACTUATOR FOR VALVELESS MICROPUMP CHARACTERISTICS

In this study, a new micropump was designed, which is suitable for medical applications regarding size and flow rate. When a micropump is used to control the amount of drug delivery, the flow rate is a key parameter and can be controlled with the diaphragm displacement. The amount of displacement depends on the thickness of the piezoelectric element, voltage, and input frequency. The simulation results showed that the displacement of the vibrating diaphragm increased with applied voltage. Moreover, when the piezoelectric thickness was increased, vibrating diaphragm displacement also was decreased. The flow rate can be adjusted by increasing or decreasing of the input voltage. Presented results also showed that the performance of the micropump was affected by the frequency of voltage. In this study, we analysed two Lead Zirconate Titanate (PZT-2) piezoelectric actuators with 50 μm and 100 μm thicknesses. The voltage values were 10 V, 20 V, 30 V, 40 V and the frequencies were 5 Hz and 10 Hz, for 3 seconds with 1 ms sensitivity. The maximum flow rate was obtained at a 50 μm thickness of PZT and its value was 3.01E-30 m3/s and the maximum displacement of the diaphragm was 1.3962 μm at 40 V and 5 Hz. Thus, the frequency and net flow rate showed an inverse correlation

Investigation of electro-mechanical factors effecting micro-pump characteristics for biomedical applications = Biyomedikal uygulamalarda kullanılan mikropompaların karakteristiğini etkileyen elektro-mekanik faktörlerin incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Geçtiğimiz birkaç on yılda, mikro-elektro-mekanik sistemler (MEMS) teknolojilerindeki gelişmeler, çeşitli fonksiyonlarda mikroakışkan cihazların hızlı gelişimine katkıda bulunmuştur. MEMS'teki önemli elemanlardan biri, dakikada mililitre (ml) veya mikrolitre (µl) arasında değişen debiler üretebilen mikropompadır. Ticari bir mikropompa, basit yapıyı ve minyatürleştirmeyi, yüksek güvenilirliği, basit çalışma prensibini, düşük maliyeti ve karmaşık denetleyiciye gerek duymayan gerekçeler sunmalıdır. Bu çalışmada, pompalama hazneleri ve sabit rezervuarlar ile yüksek debi elde edebilen iki yeni piezoelektrik aktüatörlü (kurşun zirkonat titanat-PZT) valfsiz mikropompa tasarlanmış ve imal edilmiştir. Tek Diyaframlı Mikropompa (TDM) ve Çift-Diyaframlı Mikropompa (ÇDM) akış hızları üzerindeki hidrodinamik ve elektromekaniksel etkileri araştırmak için kapsamlı deneyler yapılmıştır. ÇDM, 180 derecelik faz kaymasıyla aynı hazneye bakan iki aktüatöre sahiptir. Önerilen tasarımların temel özellikleri, yenilikçi tasarım geometrisi ile düşük giriş gerilimlerinde ve frekanslarda yüksek debilerdir. Sabit hazneli entegre mikropompalar için tek adımlı üretim sağlayan 3D baskı tekniği kullanılmıştır. Mikropompa malzemeleri biyolojik olarak uyumludur ve maliyetleri azaltmak için tekrar tekrar kullanılabilir. Silikon diyaframın çekme testi, mikroskopi teknikleri ile yüzey topografya taraması ve hidrofobik özellik için damla şekli analizi gibi mekanik parametreler yüzey ıslanma ve akış stabilitesini ortaya çıkarmak için incelenmiştir. Ek olarak, rezervuar yüksekliğinin etkisi araştırılmış ve giriş voltajının uygulanmadığı dönemlerde kalibrasyon debileri ölçülmüştür. Maksimum diyafram deplasmanı 45 V ve 5 Hz'de elde edilmiştir. TDM ve ÇDM'nin maksimum akış hızı, 45 V ve 20 Hz'de sırasıyla 32.85 ml/dak ve 35.4 ml/dak'dır. Tüm giriş voltaj ve frekans seviyelerinde, ÇDM, TDM'den daha yüksek debiye sahiptir.In the past few decades, the advances in micro-electro-mechanical systems (MEMS) technologies have contributed to the rapid development of microfluidic devices in various functions. One of the important elements on MEMS is the micro-pump, which is capable of producing flow rates ranging in milliliter (ml) or microliter (μl) per minute. A commercial micro-pump should provide properties that justify the simple structure and miniaturization, high reliability, simple working principle, low cost and no need for complex controller. In this study, two novel piezoelectric actuated (lead zirconate titanate-PZT) valveless micro-pumps that can achieve high flow rates by pumping chambers and fixed reservoirs were designed and fabricated. Extensive experiments were conducted to investigate the effects of hydrodynamic and electromechanical on flow rates of the Single Diaphragm Micro-pump (SDM) and the Bi-diaphragm Micro-pump (BDM). BDM had two actuators facing to the same chamber at 180-degree phase shift. The primary features of the proposed designs were the high flow rates at low driving voltages and frequencies with the help of innovative design geometry. 3D-printing technique providing one-step fabrication for integrated micro-pumps with fixed reservoir was used. The micro-pump materials were biocompatible and can be used repeatedly to reduce costs. Mechanical parameters such as tensile test for silicon diaphragm, surface topography scanning by microscopy techniques and drop shape analysis for hydrophobic property were investigated to reveal surface wetting and flow stability. In addition, the effect of reservoir height was investigated and the calibration flow rates were measured during the inactive periods. The maximum diaphragm displacements were obtained at 45 V and 5 Hz. The maximum flow rate of SDM and BDM at 45 V and 20 Hz were 32.85 ml/min and 35.4 ml/min respectively. At all driving voltage and frequency levels, BDM had higher flow rates than of SDM

A finite element model of the deltoid muscle and biomechanical analysis of the standing dumbbell fly for shoulder exercises

The shoulder joint participates in different resistance training due to its high mobility. In previous studies, deltoid muscle force was investigated by the electromyography method. However, the effects of increasing exercise weight on deltoid biomechanics have not been adequately studied. In this study, shoulder biomechanics in dumbbell fly movements performed with different dumbbell weights were investigated. Accordingly, the biomechanical model of the upper extremity was prepared and the motion analysis of the dumbbell fly exercise was performed. Then, the exercise was simulated with MATLAB Simscape tools. As a result of the simulation, shoulder joint moment and deltoid muscle force were calculated. Thus, the finite element model was performed to examine the mechanical behavior of the deltoid muscle during exercises. In dumbbell fly exercises performed with different weights, the maximum joint moment was 42.82 Nm, 54.32 Nm and 65.83 Nm, respectively. Additionally, the highest muscle force was calculated as 1378 N, 1750 N, and 2121 N, respectively. When the weight of the dumbbell increased by 33.33%, maximum joint moment increased by 26.85% and 21.18%, and maximum muscle force increased by 26.99% and 21.20%, respectively. However, although the dumbbell weight increased by 25%, the maximum stress in the deltoid muscle increased strikingly by 33.33%. Consequently, it was observed that increasing the weight of the dumbbell did not cause the same increase in shoulder joint moment and deltoid muscle force. Moreover, it was found that increasing the weight of the dumbbell increases the stress in the deltoid muscle to a higher extent. © 2022, The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering

Performance Comparison of Novel Single and Bi-Diaphragm PZT Based Valveless Micropumps

A commercial micropump should provide properties that justify the simple structure and miniaturization, high reliability, simple working principle, low cost and no need for complex controller. In this study, two novel piezoelectric actuated (lead zirconate titanate-PZT) valveless micropumps that can achieve high flow rates by pumping chambers and fixed reservoirs were designed and fabricated. Extensive experiments were conducted to investigate the effects of hydrodynamic and electromechanical on flow rates of the Single Diaphragm Micropump (SDM) and the Bi-diaphragm Micropump (BDM). BDM had two actuators facing to the same chamber at 180-degree phase shift. The primary features of the proposed designs were the high flow rates at low driving voltages and frequencies with the help of innovative design geometry. 3D-printing technique providing one-step fabrication for integrated micropumps with fixed reservoir was used. The micropump materials were biocompatible and can be used repeatedly to reduce costs. Mechanical parameters such as tensile test for silicon diaphragm, surface topography scanning by microscopy techniques and drop shape analysis for hydrophobic property were investigated to reveal surface wetting and flow stability. In addition, the effect of reservoir height was investigated and the calibration flow rates were measured during the inactive periods. The maximum diaphragm displacements were obtained at 45 V and 5 Hz. The maximum flow rate of SDM and BDM at 45 V and 20 Hz were 32.85 ml/min and 35.4 ml/min respectively. At all driving voltage and frequency levels, BDM had higher flow rates than of SDM

Piezoelectric micropumps: state of the art review

The purpose of this paper is to present an overview of problems and some research gaps for better understanding of piezoelectric micropump studies. Micropumps have important and diverse application areas in health and engineering applications. In recent years, researchers have carried out simulations, analytical and experimental studies to develop these technologies with different methods for the same purpose. It has been determined that piezoelectric micropumps as MEMS devices have an effective deep interest. It is worth mentioning that piezoelectric material has been considered by researchers as an attractive actuator due to its high-performance, potential cost and design convenience. This paper comprehensively reviews the studies that bring innovations in the literature of piezoelectric micropumps. Analytical characterization and modeling procedures studied by various scientists in the field of the piezoelectric actuators are also presented in detail. The analytical section will mainly focus on the studies related to the static and dynamic behaviours of circular piezoelectric actuators. Moreover, the advantages and disadvantages of the various components used to fabricate micropumps have been investigated according to the available information in the literature. Consequently, this review enables researchers a useful reference on piezoelectric micropump parameters such as modeling, flow rate, shape control, geometry, and size optimization for key engineering applications

Analytical analysis of a circular unimorph piezoelectric actuator in the range of low voltages and pressures

In this study, the static displacement behaviour of a three-layer axisymmetric circular piezoelectric unimorph actuator subjected to voltage and uniform pressure loads for different mechanical and geometric properties of layers was investigated. The closed-analytical model of piezoelectric actuator based on the classical laminated thin plate theory was performed. Kirchhoff's thin plate theory for the mathematical model in closed form of the actuator was utilized. The superposition of transverse and lateral deflections expressions was used to obtain the displacement equation of the piezoelectric actuator. Then, the analytical model solutions were compared by finite element model solutions. It was observed that the results obtained from analytical model and finite element analysis were sufficiently compatible with each other. The effects of nondimensional physical and mechanical properties on the static deflection performance of the piezoelectric actuator were discussed using the analytical model. According to the results obtained, the physical and mechanical properties of the actuator had significant effects on the actuator displacement. Therefore, the results obtained in this study can be used to optimize the performance of the circular piezoelectric actuator

Stress-Strain Response of Muscle Fibers in Biceps Brachii under Dynamic Force : An Analysis of Biceps Curl ExerciseY

One of the most important features of endurance training was to increase the weight of the dumbbells between sets. According to the relationship of the contractile force in the muscles, the porpuse was to increase muscle growth by gaining more contractile force. Previous studies had generally examined muscle behavior under maximum force. However, the relationship between increased dumbbell weight and muscle contraction was not fully investigated. The aim of this study was to investigate the mechanical behaviors resulting from the application of dynamic forces that occur during the dumbbell curl exercise on muscle fibers. In this study, biceps brachii muscle force during biceps curl exercise performed with two different weights (5kg and 10kg) was calculated. Then, a finite element model was developed and mechanical behaviors in the biceps muscle fiber during exercise were investigated. It was achieved that there was no linear correlation between dumbbell weight and muscle force. It was observed that when dumbbell weights were doubled (100%), the maximum muscle force and deformation increased by 83.13% and 84.92%, respectively. The results showed that increasing excessive weight during exercises will not be as beneficial for muscle development as expected