scholarly journals Endurance testing and finite element simulation of a modified hip stem for integration of an energy harvesting system

2021 ◽  
pp. 095441192110216
Author(s):  
Hans-E Lange ◽  
Rainer Bader ◽  
Daniel Kluess
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Energy Harvesting ◽  
Fatigue Failure ◽  
Stress Level ◽  
High Stress ◽  
Worst Case ◽  
Total Hip ◽  
Piezoelectric Energy ◽  
Energy Harvesting System

Instrumented implants are a promising approach to further improve the clinical outcome of total hip arthroplasties. For the integrated sensors or active functions, an electrical power supply is required. Energy harvesting concepts can provide autonomous power with unlimited lifetime and are independent from external equipment. However, those systems occupy space within the mechanically loaded total hip replacement and can decrease the life span due to fatigue failure in the altered implant. We previously presented a piezoelectric energy harvesting system for an energy-autonomous instrumented total hip stem that notably changes the original implant geometry. The aim of this study was to investigate the remaining structural fatigue failure strength of the metallic femoral implant component in a worst-case scenario. Therefore, the modified hip stem was tested under load conditions based on ISO 7206-4:2010. The required five million cycles were completed twice by all samples (n = 3). Additionally applied cycles with incrementally increased load levels up to 4.7 kN did not induce implant failure. In total, 18 million cycles were endured, outperforming the requirements of the ISO standard. Supplementary finite element analysis was conducted to determine stress distribution within the implant. A high stress concentration was found in the region of modification. The stress level showed an increase compared to the previously evaluated physiological loading situation and was close to the fatigue data from the literature. The stress concentration factor compared to the original geometry amounted to 2.56. The assessed stress level in accordance with the experimental fatigue testing can serve as a maximum reference value for further implant design modifications and optimisations.

scholarly journals Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5151
Author(s):  
Hans-E. Lange ◽  
Nils Arbeiter ◽  
Rainer Bader ◽  
Daniel Kluess
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Functional Model ◽  
Piezoelectric Element ◽  
Numerical Data ◽  
External Energy ◽  
Total Hip ◽  
Piezoelectric Energy ◽  
Bone Segment ◽  
Energy Harvesting System

Instrumented implants can improve the clinical outcome of total hip replacements (THRs). To overcome the drawbacks of external energy supply and batteries, energy harvesting is a promising approach to power energy-autonomous implants. Therefore, we recently presented a new piezoelectric-based energy harvesting concept for THRs. In this study, the performance of the proposed energy harvesting system was numerically and experimentally investigated. First, we numerically reproduced our previous results for the physiologically based loading situation in a simplified setup. Thereafter, this configuration was experimentally realised by the implantation of a functional model of the energy harvesting concept into an artificial bone segment. Additionally, the piezoelectric element alone was investigated to analyse the predictive power of the numerical model. We measured the generated voltage for a load profile for walking and calculated the power output. The maximum power for the directly loaded piezoelectric element and the functional model were 28.6 and 10.2 µW, respectively. Numerically, 72.7 µW was calculated. The curve progressions were qualitatively in good accordance with the numerical data. The deviations were explained by sensitivity analysis and model simplifications, e.g., material data or lower acting force levels by malalignment and differences between virtual and experimental implantation. The findings verify the feasibility of the proposed energy harvesting concept and form the basis for design optimisations with increased power output.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

Effective Piezoelectric Area for Hitting-Type Piezoelectric Energy Harvesting System

2013 ◽  
Vol 52 (10S) ◽  
pp. 10MB03 ◽  
Author(s):  
Hyun Jun Jung ◽  
Daniel Song ◽  
Seong Kwang Hong ◽  
Yooseob Song ◽  
Tae Hyun Sung
Keyword(s):  
Energy Harvesting ◽  
Piezoelectric Energy Harvesting ◽  
Piezoelectric Energy ◽  
Energy Harvesting System

A Creative Vibration Energy Harvesting System to Support a Self-Powered Internet of Thing (IoT) Network in Smart Bridge Monitoring

2020 ◽  
Author(s):  
Saman Farhangdoust ◽  
Claudia Mederos ◽  
Behrouz Farkiani ◽  
Armin Mehrabi ◽  
Hossein Taheri ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Cantilever Beam ◽  
Average Power ◽  
Electrical Energy ◽  
Laser Vibrometer ◽  
Stay Cable ◽  
Fe Modelling ◽  
Vibration Energy Harvesting ◽  
Piezoelectric Energy ◽  
Energy Harvesting System

Abstract This paper presents a creative energy harvesting system using a bimorph piezoelectric cantilever-beam to power wireless sensors in an IoT network for the Sunshine Skyway Bridge. The bimorph piezoelectric energy harvester (BPEH) comprises a cantilever beam as a substrate sandwiched between two piezoelectric layers to remarkably harness ambient vibrations of an inclined stay cable and convert them into electrical energy when the cable is subjected to a harmonic acceleration. To investigate and design the bridge energy harvesting system, a field measurement was required for collecting cable vibration data. The results of a non-contact laser vibrometer is used to remotely measure the dynamic characteristics of the inclined cables. A finite element study is employed to simulate a 3-D model of the proposed BPEH by COMSOL Multiphasics. The FE modelling results showed that the average power generated by the BPEH excited by a harmonic acceleration of 1 m/s2 at 1 Hz is up to 614 μW which satisfies the minimum electric power required for the sensor node in the proposed IoT network. In this research a LoRaWAN architecture is also developed to utilize the BPEH as a sustainable and sufficient power resource for an IoT platform which uses wireless sensor networks installed on the bridge stay cables to collect and remotely transfer bridge health monitoring data over the bridge in a low-power manner.

Multimodal Energy Harvesting System: Piezoelectric and Electromagnetic

2008 ◽  
Vol 20 (5) ◽  
pp. 625-632 ◽  
Author(s):  
Yonas Tadesse ◽  
Shujun Zhang ◽  
Shashank Priya
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Permanent Magnet ◽  
Cantilever Beam ◽  
Piezoelectric Energy Harvesting ◽  
Prototype System ◽  
Finite Element Software ◽  
Piezoelectric Energy ◽  
Energy Harvesting System ◽  
Tip Mass

In this study, we report a multimodal energy harvesting device that combines electromagnetic and piezoelectric energy harvesting mechanism. The device consists of piezoelectric crystals bonded to a cantilever beam. The tip of the cantilever beam has an attached permanent magnet which, oscillates within a stationary coil fixed to the top of the package. The permanent magnet serves two purpose (i) acts as a tip mass for the cantilever beam and lowers the resonance frequency, and (ii) acts as a core which oscillates between the inductive coils resulting in electric current generation through Faraday's effect. Thus, this design combines the energy harvesting from two different mechanisms, piezoelectric and electromagnetic, on the same platform. The prototype system was optimized using the finite element software, ANSYS, to find the resonance frequency and stress distribution. The power generated from the fabricated prototype was found to be 0.25 W using the electromagnetic mechanism and 0.25 mW using the piezoelectric mechanism at 35 g acceleration and 20 Hz frequency.

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