Mechanical Engineering Commons^™

A Substructuring Technique With Application To Spot Weld Placement Design, Yang Wang

Mechanical & Aerospace Engineering Theses & Dissertations

It is quite common in the industry to use various interface methods, such as welding, fasteners, bolts, adhesive bonding, etc., to join substructures together. The quality of the assembled structure is directly related to the type of the interface methods used in the manufacturing process. Thus, it is important to include the interface conditions as part of design variables in any design process. To this end, this work develops a reanalysis method that can efficiently analyze structures with variations on the interface conditions. This reanalysis method is based upon a new two-step substructuring technique. The first step performs substructural level …

Elastic Properties, Strength And Damage Tolerance Of Pultruded Composites, Mrinal Chandra Saha

Mechanical & Aerospace Engineering Theses & Dissertations

Pultruded composites are candidate materials for civil engineering infrastructural applications due their higher corrosion resistance and lower life cycle cost. Efficient use of materials like structural members requires thorough understanding of the mechanism that affects their response. The present investigation addresses the modeling and characterization of E-glass fiber/polyester resin matrix pultruded composites in the form of sheets of various thicknesses.

The elastic constants were measured using static, vibration and ultrasonic methods. Two types of piezoelectric crystals were used in ultrasonic measurements. Finally, the feasibility of using a single specimen, in the form of a circular disk, was shown in measuring …

Mathematical Modeling For Fabricating A Microstructure With A Pre-Specified Geometry Using Laser -Induced Chemical Vapor Deposition, Chaoyang Zhang

Doctoral Dissertations

Laser-induced chemical vapor deposition (LCVD) is an emerging new technique with many practical applications. To optimize the system for fabricating a microstructure with a pre-specified geometry in pyrolytic LCVD, a three-dimensional mathematical model is developed for predicting temperature distributions and laser dwell times across the substrate scanned by the laser beam. A microstructure is fabricated layer by layer, and for each layer the laser beam moves from one pixel to the next. The complicated correlations among temperature distribution, deposit growth rate, and laser dwell time are investigated. A purely heterogeneous reaction is assumed and any gas-phase transport is ignored.

A …