A Study of Life Cycle Costing in the Perspectives of Research and Commercial Applications in the 21st Century

This paper presents a review of research in the area of life cycle costing and offers a critique of current commercial cost estimation systems. The focus of the review is on relevant academic research on life cycle cost from 2000 onwards. In addition to this a comparison of the current cost estimation systems is presented. Using the review findings and industrial investigations as a base, a set of mathematical representations for design and manufacturing costs and the introduction of the critical factors is proposed. These are considered in terms of the operational, maintenance and disposal costs to create a method for ascertaining the life cycle cost estimate for complex products. This is presented using as an exemplar, research currently being undertaken in the area of low volume and long life electronic products in the UK defence sector. The benefit of the method proposed is that it aims to avoid the inflexibility of traditional approaches which usually require historical and legacy data to support the cost estimation processes.

Stress Intensity Factor Calculation Using a Weight Function Method

Propagation of a critical unstable crack under the action of static or varying stresses is determined by the intensity of strain field at tips of the crack. Stress intensity factor (SIF) is an important parameter in fracture mechanics, which is used as a criterion to judge the unstable propagation of a crack and plays an important role in calculating crack propagation life. SIF is related to both geometrical form and loading condition of a structure. In the paper, a weight function method is introduced to study crack propagation of center through cracks and edge cracks in a finite-size plate. In addition, finite element method, linear regression, and polynomial interpolating technique are used to simulate and verify the proposed method. Comparison studies among the proposed and current methods are performed as well. The results show that the weight function method can be used to calculate SIF easily.

Robust Layout Synthesis of a MEM Crab-Leg Resonator Using a Constrained Genetic Algorithm

The research work carried out in this paper introduces a robust design method for layout synthesis of MEM resonator subject to inherent geometric uncertainties such as the fabrication error on the sidewall of the structure. The robust design problem is formulated as a multi-objective constrained optimization problem with certain assumptions and treated by a special constrained genetic algorithm. The MEM design used for validation is a crab-leg resonator taken from the literature. The results show that the approach proposed in this research can lead to design results that meet the target performance and are less sensitive to geometric uncertainties than typical designs.

Contact Stress Analysis of Gear of Crane Gearbox

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.

Computer-Aided Laboratory Work to “Mechanism and Machine Science” Course

Laboratory work is an important element in engineering training, which should correspond to up-to-date tendencies in computer-based technologies in design, production, maintenance and preserving mechanisms. Computer-based laboratory work consists of 16 assignments. Seven assignments are carried out on laboratory stands, the remainder are provided on PC, using programs like “Visual Structure Editor”, “DYNAMO”, “APM Win Machine”. The system Visual Structure Editor (VSE) is designed by specialists of “Machine Mechanics and Computer-Aided Design” department, of the Maritime State University named after adm.G.I.NEVELSKOY, Vladivostok, under the direction of prof. Valentina V. Kuzlyakina. The system APM (Automated Projecting of Mechanism) is designed by the research-and-production centre “APM” under the direction of prof.V.Shelofast, from the city of Korolyov, Moscow area. These systems are multifunctional. They allow project different mechanical systems at the stage of structural and parametrical synthesis, carry out strength calculations and design elements of machines and mechanisms. They are good in operation. Teachers and students easily master the systems. Laboratory works with computer support allow students to pass from a concrete object to modeling on a PC, and to solve complex engineering tasks during the education process.

Tactile Whole-Field Imaging Sensor on Photoelasticity

The paper describes a whole-field imaging sensor developed on the principles of photoelasticity. The sensor produces colored fringe patterns when load is applied on the contacting surface. These fringes can be analyzed using conventional photoelastic techniques, however, as the loading in the present case is not conventional some new strategies need to be devised to analyze the load imprint. The loading is unconventional in the sense that low modulus photoelastic material is deformed under vertical load in the direction of light travel to induce the photoelastic effect. The paper discusses the efficacy of both RGB calibration and phase shifting techniques in sensing applications. The characteristics of fringe patterns obtained under vertical and shear loads have been studied and the results obtained under these conditions are discussed with their limitations specifically when this is applied for sensing applications. Finally a case study has been conducted to analyze a foot image and conclusions drawn from this have been presented.

Applying Lean Manufacturing Principles to Revolutionize Cubrside Equipment and Collection Processes

The application of lean manufacturing principles has improved the production flow of manufacturing companies across the globe. In a similar vein, environmentally conscious design has been an increasingly important avenue of research which similarly seeks to reduce waste and thereby mitigate environmental impact. An analysis of the curbside municipal solid waste (MSW) and recycling collection process from a lean manufacturing standpoint reveals numerous non-value added activities which can be eliminated or reduced and value-added activities which can be made more efficient. Environmental America Inc. (EAI) has proposed a collection process which will improve the overall material flow through the use of a collection vehicle specializing in the combined collection of raw waste and recyclable waste. This collection vehicle, combined with localized, low-impact material offloading facilities has the potential to revolutionize the curbside collection process. Our research supports this vision by configuring the truck layout and process operations, as discussed in this paper.

An Application of Relay Feedback to Mass Measurement Under Weightless Conditions

Relay feedback was applied to measuring mass even under weightless conditions. A measurement object is driven by a force-output actuator. The motion of the object is controlled by a relay feedback system. The used relay element has dead zone and switches force acting on the object in relation to the position of the measurement object. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. An apparatus was developed for experimental study. It uses a voice coil motor as an actuator, and a pair of photo interrupters for detecting the switching positions. The effects of system parameters on measurement accuracy were studied experimentally. Under the tuned conditions, the measurement errors were within 0.2[%]. Measurement on a base moving freely was also carried out.

Embracing Product Design Engineering

A Product Design and Manufacturing (PDM) Engineering emphasis has been designed to update a Manufacturing Engineering program at Grand Valley State University. While the program continues to include a major focus on manufacturing it also emphasizes crossing disciplinary boundaries for product design. Graduates of the program are educated to work in all phases of the product development process from concept to customer. The program includes a blend of courses from a variety of disciplines, tieing these together using a sequence of product design courses. Within the courses students are exposed to course work that encourages product oriented design including prototyping. The program redesign described in the paper could also be applied to Mechanical Engineering programs.

Application of Tablet Computers in a Capstone Design Course

Tablet PCs look much like regular laptop computers, except their digitized screens can be swiveled around, folded over, and written on with a stylus. Instructors have recognized that this simple write-on feature gives them the opportunity to change the way in which they lecture in a classroom. This paper examines the application of tablet PCs outside of the lecture hall. Specifically, it describes the application of tablet computers to a final year capstone design course. Particular applications include the replacement of the traditional individual design notebook with a shared electronic notebook and enhancement of sketching as a communication tool. A description of the capstone course is given to provide a context for how the tablets were used. The impact of the tablet PCs is discussed and the results of a user survey are presented.