The application of encapsulation material stability data to photovoltaic module life assessment

For any piece of hardware that degrades when subject to environmental and application stresses, the route or sequence that describes the degradation process may be summarized in terms of six key words: LOADS, RESPONSE, CHANGE, DAMAGE, FAILURE, and PENALTY. Applied to photovoltaic modules, these six factors form the core outline of an expanded failure analysis matrix for unifying and integrating relevant material degradation data and analyses. An important feature of this approach is the deliberate differentiation between factors such as CHANGE, DAMAGE, and FAILURE. The application of this outline to materials degradation research facilitates the distinction between quantifying material property changes and quantifying module damage or power loss with their economic consequences. The approach recommended for relating material stability data to photovoltaic module life is to use the degree of DAMAGE to (1) optical coupling, (2) encapsulant package integrity, (3) PV circuit integrity or (4) electrical isolation as the quantitative criterion for assessing module potential service life rather than simply using module power loss

MOD-0A 200 kW wind turbine generator design and analysis report

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented

NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 04)

For abstract, see N74-20609

Development of an Instrumented and Powered Exoskeleton for the Rehabilitation of the Hand

With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy

Structural analysis of a composite monocoque chassis for use in a high performance electric vehicle.

Masters Degree. University of KwaZulu-Natal. DurbanThe adoption of electric vehicle technology is becoming more prevalent, as society strives to reduce the negative impact of greenhouse gas emissions and focuses on a sustainable future. This thesis details the design and structural analysis of a carbon composite monocoque chassis for application in a light-weight, high-performance electric vehicle for a South African market, based on the fundamental principles of automotive vehicle design. Handling characteristics and the design impacts they have on the decisions made in developing a vehicle chassis were explored. The two-dimensional geometry of the chassis structure was developed in the Siemens NX design environment, taking into account the spatial requirements of the mechanical and electrical system components, as well as occupant ergonomics. A zonedbased approach was taken in defining the composite layup for the chassis panels, using material data for locally obtained fabrics and epoxy resin. The chassis’ composite lay-up configuration was developed using several static load cases, simulating operational loading, as well as extreme loading arising in certain accident scenarios. The composite structure was analysed, with the first ply composite failure criterion being used to predict failure in the constituent materials. Design refinement was undertaken until the failure criterion predicted structural survivability for all the extreme loading cases considered

Design and analysis of a hybrid timber-steel floating substructure for a 15 MW semisubmersible-type FWT

Wind energy has developed to be among the most promising sources of renewable energy. Furthermore, floating offshore wind turbines have presented the opportunity for higher power production in intermediate (45-150 m) and deep water (> 150 m). However, the manufacturing, installation, and operation of wind turbines in general, and floating wind turbines in particular, can result in significant amounts of greenhouse gas emissions (GHG). This thesis proposes a novel design of a hybrid timber-steel floating substructure for the IEA 15 MW floating wind turbine. The new design presents a modified version of the UMaine VolturnUS-S semisubmersible platform that was initially developed for the same turbine. The main objective of the new design is to reduce the turbine’s overall CO2 footprint. This objective is achieved by replacing structural steel with glued laminated timber, a more sustainable material known for its environmental benefits. Firstly, a robust design methodology is introduced. Secondly, Ansys workbench 2020 R1 is utilized to compare and then select between three preliminary hybrid timber-steel models based on a set of criteria that are extracted from relevant standards for both timber and steel. Compared to the UMaine VolturnUS-S semisubmersible platform, the selected hybrid configuration provides a considerable reduction in the steel mass (around 590 t). Subsequently, fully coupled aero-hydro-servo-elastic dynamic analysis is carried out using OpenFAST to validate the selected model. Only the ultimate limit state design (ULS) for the turbine under extreme and normal operating conditions is considered. The results from the numerical analysis show that the selected model fulfills all design criteria with a utilization factor that varies between 74- 94% for the different design load cases. In the end, the work concludes that the glulam-based supporting structure offers an effective load-bearing solution for the IEA 15 MW turbine, contributing to the development of floating wind energy with minimal cost and CO2 footprint. However, a series of tasks and suggestions are proposed to enhance the process of developing an optimal timber-steel design

Global and Local Structural Health Monitoring Methods Based on Wireless Telemetry and Boundary-based Thermography

Our nation’s economy is dependent upon its transportation system for the movement of people, goods and services. Infrastructure plays a vital role in supporting transportation services. Given their importance, structures must be maintained to offer safe and reliable operations over extended life-cycles. Structural health monitoring (SHM) has emerged to offer owners a quantitative approach to monitoring structures, assessing system performance and estimating structural conditions. While SHM systems have been successfully deployed to structures, their full potential has not been reaped due to the gap that exists between SHM data and the decision-making needs of owners. This thesis contributes to the field by bridging this gap through two approaches. First, the thesis explores the advancement of wireless monitoring systems whose instrumentation strategy is defined by the needs of the decision-making process of the owner. This is illustrated in the thesis by exploring wireless monitoring systems and associated data-to-decision (D2D) frameworks in the United States Coast Guard (USCG) high-speed aluminum Response Boat-Medium (RB-M) and in the Harahan Bridge. In the former, the wireless hull monitoring system is tailored to derive RB-M hull response data over a short-period to create relationships between the environmental and operational conditions (EOC) of the vessel and the accumulation of fatigue in a critical hull component. In doing so, the vessel owner can make life-cycle decisions centered on managing fatigue accumulation by considering the future operational profile of the vessel. In the latter application, a wireless monitoring system is installed on the Harahan Bridge (which is a steel truss railroad bridge) to monitor bridge responses to triggered load events including trains, collisions, and earthquakes. Again, a fatigue critical eyebar element is considered with an alerting framework created to alert the bridge owner of overloading conditions that can accelerate fatigue accumulation. While the two case studies showcase clear benefits to designing wireless monitoring systems around the decision-making of the asset owner, they also highlight the value of local structural measurements for component health assessment. To extend the benefits offered by local sensing further, the thesis explores the creation of a cost-effective approach to damage detection through thermal conduction. Using point heaters and temperature sensors, a thermal-based computed tomography (CT) image reconstruction method is developed for two-dimensional (2D) mapping of structural conditions. This powerful local damage imaging method is implemented using a wireless impedance analyzer developed for use in structural wireless monitoring systems. In summary, a new approach to designing SHM systems is developed that looks first at the desired outcome, or decision that the data should inform. This is showcased in two unique wireless monitoring system and D2D framework studies. Next, a novel thermal imaging technique is proposed and validated. Lastly, a first-of-its-kind multi-functional wireless impedance analyzer is developed that is capable of enabling the wireless and permanent installation of multiple spatial sensing techniques.PHDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138654/1/nephi_1.pd

Dynamic design of a cube-shaped satellite excited by launch vibrations

The objective of this Final Project is the structural design of a small cube–shaped satellite. Its primary structure should endure all launching vibrations. To fulfil that objective, a 3D Model of the satellite and a dynamic analysis must be done. The satellite has been designed as a multipurpose platform, so it can satisfy all possible client requirements in order to put different payloads into orbit. To begin with, a general satellite with an arbitrary payload has been designed with the future intention to adapt the current design to each client if necessary. To address the problem the following procedure has been used. First, and with a multi–platform CAD/CAM/CAE commercial software suite called CATIA (Computer Aided Three–Dimensional Interactive Application) a Computer Aided Design Model must be designed. Later, once the parameterized model is created, the engineering simulation software (CAE) ANSYS will be used to study the structural behaviour of the satellite during launch. The scope of this project is to design a multipurpose satellite bus that satisfies the conditions of the ASAP Document (see Section 6.1). That is, a satellite which can withstand all inertial forces and loads during launch in the 0–100 Hz spectrum, with a correctly aligned center of gravity, small enough moments of inertia, and with its natural frequencies above a certain value for each axis. The bus must fulfil the specifications given by the corresponding launch vehicle1 manufacturer, so to choose the launch vehicle, a comparative study has been made between the different options evaluating reliability, availability of the information offered and payload requirements. Once this study has been carried out, the most restrictive launcher has been selected. This has been done in order to be able to use a wider range of LV.Fraile Izquierdo, S.; Pila Vigalondo, A. (2014). Dynamic design of a cube-shaped satellite excited by launch vibrations. Universitat Politècnica de València. http://hdl.handle.net/10251/50741Archivo delegad

Applications of Finite Element Modeling for Mechanical and Mechatronic Systems

Modern engineering practice requires advanced numerical modeling because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Thus far, different methods have been used to implement the real structure into the numerical version. The most popular uses have been variations of the finite element method (FEM). The aim of this Special Issue has been to familiarize the reader with the latest applications of the FEM for the modeling and analysis of diverse mechanical problems. Authors are encouraged to provide a concise description of the specific application or a potential application of the Special Issue