Todd Alan Anderson

A vibration energy harvesting sensor platform for increased industrial efficiency

A model for piezoelectric vibration energy harvesting with a piezoelectric cantilever beam is presented. The model incorporates expressions for variable geometry, tip mass, and material constants, and allows the parameterized determination of the voltage and power produced over a purely resistive load. The model is of a lumped-element form, with the base excitation acceleration and voltage representing the effort variables, and the tip velocity and electrical current representing the flow variables. Subsequent to the models derivation, experimental results are presented and demonstrate the accuracy of the model. As peak power output for existing vibration configurations is typically of interest, several simple optimization studies are then performed on a simple generator configuration to demonstrate the effects of several of the driving geometric and material parameters.

Steady state and dynamic modeling of RO desalination modules and system using EES

In this article, we introduce a powerful software tool Engineering Equation Solver (EES) and apply it to create steady state and dynamic models for a reverse osmosis (RO) desalination system. EES is a general equation-solving program that can numerically solve thousands of coupled nonlinear algebraic equations. It can also be used to solve differential equations and optimization problems. In RO desalination system design, amount of coupled differential equations related to mass balance and momentum balance need to be solved to develop system model. Hence, by applying EES to solve differential equations is a very efficient and effective method to build RO desalination system model. Comparing with Matlab, EES has the advantage of easy programming and fast convergence speed. It significantly reduces the time spending for programming to solve nonlinear equations and researchers can focus on RO system optimal design and analysis.

Flexible Fiber-reinforced Pipe for 10,000-foot Water Depths: Performance Assessments and Future Challenges

The primary aim of the present composite development program is to enhance access to deepwater fields in the Gulf of Mexico, Brazil, and West Africa. To accomplish that goal, composite materials are being incorporated in unbonded flexible pipelines to lower mass and enhance the overall system performance to expand the operational design envelope. In addition, the use of composite materials will allow a significant improvement in pipe operating pressure (>70 MPa), pipe operating temperature (>125C) and due to increased CO2 and H2S resistance, will improve sour service performance and lifespan. Composite materials are well known for their low density and high specific strength, stiffness and fatigue performance. These properties are desirable and will certainly enhance pipe performance, but the overall performance of the pipe during all stages of manufacture and deployment must be considered, as well as a conservative approach to introducing these new materials. Some of the key factors that need to be assessed are material failure modes under varied pipe loadings, dynamic interactions and exposure to severe oil field environments. There are several individual standards, specifications and joint industry projects (JIPs) focused on composite pipes that address some of these issues, but there is also a general lack of consensus with regard to testing standards and understanding of the long-term performance. As flexible pipe suppliers, the industry must aim to provide performance assessments and address all key challenges to allow the flexible pipe industry to build confidence in the new and enabling composite pipe technologies. In a previous paper, we presented design concepts and a toolbox approach to construct different composite pipe solutions to meet all the aforementioned performance parameters. The present paper selectively highlights important failure modes and design considerations, demonstrates an understanding of behavior in the matrix and fiber phases, and addresses concerns related to the chemical performance of composite materials. The present paper also highlights and addresses some of the concerns of composite pipes and focuses on areas for future development and testing. These results will support the selection and standardization of analysis tools and testing methods across the industry. Bespoke testing capabilities to address the relevant failure mechanisms and installation strategies for composite pipes will also be discussed.