Studies of numerical methods to decouple structure and fluid interaction have reported the need for more precise approximations of higher structure eigenvalues and eigenvectors than are currently available from standard finite elements. The purpose of this study is to investigate hybrid finite element models composed of standard finite elements and exact-elements for the prediction of higher structure eigenvalues and eigenvectors. An exact beam-element dynamic-stiffness formulation is presented for a plane Timoshenko beam with rotatory inertia. This formulation is based on a converted continuum transfer matrix and is incorporated into a typical finite element program for eigenvalue/vector problems. Hybrid models using the exact-beam element generate transcendental, nonlinear eigenvalue problems. An eigenvalue extraction technique for this problem is also implemented. Also presented is a post-processing capability to reconstruct the mode shape each of exact element at as many discrete locations along the element as desired. The resulting code has advantages over both the standard transfer matrix method and the standard finite element method. The advantage over the transfer matrix method is that complicated structures may be modeled with the converted continuum transfer matrix without having to use branching techniques. The advantage over the finite element method is that fewer degrees of freedom are necessary to obtain good approximations for the higher eigenvalues. The reduction is achieved because the incorporation of an exact-beam-element is tantamount to the dynamic condensation of an infinity of degrees of freedom. Numerical examples are used to illustrate the advantages of this method. First, the eigenvalues of a fixed-fixed beam are found with purely finite element models, purely exact-element models, and a closed-form solution. Comparisons show that purely exact-element models give, for all practical purposes, the same eigenvalues as a closed-form solution. Next, a Portal Arch and a Verdeel Truss structure are modeled with hybrid models, purely finite element, and purely exact-element models. The hybrid models do provide precise higher eigenvalues with fewer degrees of freedom than the purely finite element models. The purely exact-element models were the most economical for obtaining higher structure eigenvalues. The hybrid models were more costly than the purely exact-element models, but not as costly as the purely finite element models. / Ph. D.

The displacement method of the finite element is adopted. Both the updated Lagrangian formulation and total Lagrangian formulation of a three-dimensional beam element is employed for large displacement and large rotation, but small strain analysis. A beam-column element or finite element can be used to model geometrically nonlinear behavior of space frames. The two element models are compared on the basis of their efficiency, accuracy, economy and limitations. An iterative approach, either Newton-Raphson iteration or modified Riks/Wempner iteration, is employed to trace the nonlinear equilibrium path. The latter can be used to perform postbuckling analysis. / Ph. D.

工程產業一直扮演著產業火車頭的角色，台灣歷經多次的景氣循環，而工程產業的發展一直與景氣有著密不可分的關係；然而工程產業雖與景氣雖有著高度關聯性，但相較於其他產業的發展模式而言，卻具有相當高之差異度，因此本文對於工程產業之模式與發展欲進行較深入之分析；再者，台灣目前對於工程產業的分析文獻並不多見，並且大都著眼於大型工程公司的成功經驗，或是其發展成功之制度架構，但無法暸解該成功經驗之累積過程或是制度架構之轉換過程。而本研究欲對於現況進行突破，除針對成功發展經驗的累積及制度架構的轉換進行整合及連續性的分析，更引用個案A公司的實際中小型企業的案例，來觀察A公司的發展歷程，了解企業由小規模發展至中大規模的發展途徑上，可能的成功路徑與發展模式，並且由於個案A公司歷經台灣多次的景氣循環，其發展的經驗以及發展歷程更是彌足珍貴，對於台灣的中小型企業發展上，可提供有效的建議。 本文藉由產業價值鏈分析法，對於工程產業進行深入的分析，再藉由司徒老師所創制之策略矩陣，將產業價值鏈作為橫向面，與縱向面的產品策略構面及產業策略構面進行結合，賦予策略矩陣中的各「策略點」全新的邏輯與意義，以便於作為策略決策的連續動態過程的解釋。文中並舉以實際個案A公司之資料以及重大發展歷程與轉折，利用策略矩陣分析法，針對A公司進行分析，觀察其發展過程及決策過程。 / This paper will apply the strategic matrix which developed by Dr. Szu-Tu, utilizing a completely new strategic management perspective, to examine the relation between engineering industry and the transition of industry. The strategic matrix method was developed from industrial value chain and strategic types and is a logical procedure of strategic analysis and decision-making. It is very useful for analyzing the commercial environment, to know the operational features of the individual industry, and to determine the strengths of businesses. The strategic matrix method is often applied in the manufacturing industry due to the feasibility of determining the industrial value chain of the manufacturing industry. However, unlike the manufacturing industry, the industrial value chain of the engineering industry in this paper is difficult to determine. And most of the past studies discuss about engineering industry were aim at key-success factors of strategic management, but the paper to observe the dynamic process of the strategy for engineering industry is not exist. For the above reasons, this paper will perform the dynamic process between value chain and strategic dimensions, and providing the suggestions about how to improve the competitiveness for small and medium-sized enterprises in Taiwan.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

In this thesis, frontal subroutines are implemented to a plane frame analysis program for execution on the IBM PC. The resulting program solves for the unknown joint displacements of frame structures with large numbers of degrees of freedom by utilizing a peripheral back-up storage; which can not be analyzed directly in core. A comparison of the frontal solver and the out-of-core band solver is presented. / M.S.

Structural health monitoring (SHM) is concerned with the continuous, long-term assessment of structural integrity. One commonly investigated SHM technique uses guided ultrasonic waves, which travel through the structure and interact with damage. Measured signals are then analyzed in software for detection, estimation, and characterization of damage. One common configuration for such a system uses a spatially-distributed array of fixed piezoelectric transducers, which is inexpensive and can cover large areas. Typically, one or more sets of prerecorded baseline signals are measured when the structure is in a known state, with imaging methods operating on differences between follow-up measurements and these baselines. Presented here is a new class of SHM spatially-distributed array algorithms that rely on sparse reconstruction. For this problem, damage over a region of interest (ROI) is considered to be sparse. Two different techniques are demonstrated here. The first, which relies on sparse reconstruction, uses an a priori assumption of scattering behavior to generate a redundant dictionary where each column corresponds to a pixel in the ROI. The second method extends this concept by using multidimensional models for each pixel, with each pixel corresponding to a "block" in the dictionary matrix; this method does not require advance knowledge of scattering behavior. Analysis and experimental results presented demonstrate the validity of the sparsity assumption. Experiments show that images generated with sparse methods are superior to those created with delay-and-sum methods; the techniques here are shown to be tolerant of propagation model mismatch. The block-sparse method described here also allows the extraction of scattering patterns, which can be used for damage characterization.

Numerical methods are often required to solve chemical problems, either to verify theoretical models or to access information that is not readily available experimentally. This thesis deals with both situations, though in differing levels of detail. A major component of this thesis is devoted to developing new methods to determine a full eigendecomposition of the matrices derived from "low temperature" unimolecular master equations. When transient behaviour is of interest achieving relative accuracy for more than just the eigenvector corresponding to the smallest eigenvalue is of central importance. Three new methods are presented. The first is based on a weighted implementation of subspace projection methods, in this case explored for the well-known Arnoldi method. This weighted inner product subspace projection methodology is demonstrated to

Numerical methods are often required to solve chemical problems, either to verify theoretical models or to access information that is not readily available experimentally. This thesis deals with both situations, though in differing levels of detail. A major component of this thesis is devoted to developing new methods to determine a full eigendecomposition of the matrices derived from "low temperature" unimolecular master equations. When transient behaviour is of interest achieving relative accuracy for more than just the eigenvector corresponding to the smallest eigenvalue is of central importance. Three new methods are presented. The first is based on a weighted implementation of subspace projection methods, in this case explored for the well-known Arnoldi method. This weighted inner product subspace projection methodology is demonstrated to

Numerical methods are often required to solve chemical problems, either to verify theoretical models or to access information that is not readily available experimentally. This thesis deals with both situations, though in differing levels of detail. A major component of this thesis is devoted to developing new methods to determine a full eigendecomposition of the matrices derived from "low temperature" unimolecular master equations. When transient behaviour is of interest achieving relative accuracy for more than just the eigenvector corresponding to the smallest eigenvalue is of central importance. Three new methods are presented. The first is based on a weighted implementation of subspace projection methods, in this case explored for the well-known Arnoldi method. This weighted inner product subspace projection methodology is demonstrated to

Numerical methods are often required to solve chemical problems, either to verify theoretical models or to access information that is not readily available experimentally. This thesis deals with both situations, though in differing levels of detail. A major component of this thesis is devoted to developing new methods to determine a full eigendecomposition of the matrices derived from "low temperature" unimolecular master equations. When transient behaviour is of interest achieving relative accuracy for more than just the eigenvector corresponding to the smallest eigenvalue is of central importance. Three new methods are presented. The first is based on a weighted implementation of subspace projection methods, in this case explored for the well-known Arnoldi method. This weighted inner product subspace projection methodology is demonstrated to