Instability of cylindrical shells subjected to axisymmetric moving loads

Instability of infinite length cylindrical shell subjected to axisymmetric load

Unsymmetrical large deflections of expulsion devices, tasks 1 and 2 Final report

Design of bladder expulsion device subjected to constraints such as cycle life, chemical inertness, and storabilit

Stability of cylindrical shells under axisymmetric moving loads

Cylindrical shell stability under axisymmetric moving load

Seismic Behavior of Cold-Formed Steel Shear Walls during Full-Scale Building Shake Table Tests

Cold-formed steel sheathed shear walls are now emerging as a strategic vertical lateral load resisting component in seismic design. However, although a number of component cyclic test programs have been conducted in recent years to characterize their hysteretic behavior and guide design, system-level test programs to investigate their performance are so far lacking in the literature. To this end, a unique full-scale CFS-framed mid-rise building shake table test program was conducted to contribute to understanding the behavior of mid-rise cold-formed steel (CFS) wall-braced buildings under a multi-hazard scenario. The centerpiece of this project involved earthquake and live fire testing of a full-scale six-story CFS wall braced building constructed on the Large High Performance Outdoor Shake Table (LHPOST) at UCSD. This paper first provides a brief overview of the test program and summarizes the system-level (global) response of the test building during the shake table tests. Subsequently, a key focus of this paper is comparison of the component-level responses of various shear wall systems of the test building as well as their physical damage

Vapor Cloud Explosion Live Test and Data Analysis Development Program

PresentationVapor Cloud Explosions (VCE), an ever-present threat to the petroleum refining industry, create hazards to employees, equipment and production capabilities. To mitigate the effect of these hazards, effective designs for structural and non-structural components must be developed and confirmed via experimental validation to ensure the safety and performance of the facility and its occupants. Current methodologies for full-scale VCE performance testing involve the use of large quantities of high explosives set at a large standoff distance to achieve the time durations common in VCE events. While effective in achieving the peak pressures involved, these tests do not adequately characterize the full behavior of the time-dependent loading conditions and other effects seen in VCE events, such as enhanced turbulence, degree of confinement and the reactivity of unburned materials. The explosive testing community recognizes that current testing methods do not fully characterize the loading behavior and that only a small number of large- scale VCE tests have been conducted by various commercial and government agencies. Unfortunately, most of the work has been in support of counterterrorism efforts, making the test data unavailable to the petroleum industry

Axisymmetric Waves in Layered Anisotropic Fibers and Composites

The complicated morphology of the new generation of advanced fibrous composites gave further impetus to the study of the interaction of ultrasonic waves with multilayered concentric cylindrical systems. Typically, the fiber consists of a cylindrical core embedded in a cladding region followed by a distinct interface zone separating the fiber system from the host (matrix) region. In addition, the cladding region itself often consists of subregions which can be identified as distinct layers. Each individual layer can posses certain degree of microscopic anisotropy adding to the macroscopic anisotropy produced by the presence of layering and imperfect interfaces. Relatively few efforts have been spent upon the study of free and immersed homogeneous anisotropic rods [1–5]. These works are insufficient to model real situations encountered in materials characterization of advanced fibrous composites. In order to better model advanced fibrous composites at least three major effects need to be accounted for. These are the inhomogeneous nature of the structure as reflected in its multilayering, the inherent microscopic anisotropy of some of the constituents and finally the quality of the interfaces. In this paper we briefly describe a unified analytical treatment of wave propagation along the fiber direction of multilayered coaxial fibrous systems embedded in a host material. A more detailed discussion of this general treatment will be presented elsewhere [6]. Figure 1 shows typical geometric situations including (a) a single multilayered fiber, (b) a single multilayered fiber either immersed in an infinite fluid or embedded in an infinite solid, and an infinite composite material with periodically distributed multilayered fiber

Experimental Performance of Concrete Columns with Composite Jackets under Blast Loading

Measures to prevent progressive collapse of structures include protection of critical elements such as columns. In support of this goal, nine tests were conducted to assess the as-built performance of typical columns and the effectiveness of carbon fiber jackets in improving their performance. A quasi-static load protocol was developed to replicate in the laboratory the damage patterns observed in blast testing in the field. Load-deflection curves (resistance functions) and jacket strain were measured. Jackets were observed to change the failure mode from brittle shear to ductile flexure and to increase the load and displacement capacities of the column. Variations in jacket strain are discussed and experimental results are used to assess predictive models for shear capacity and resistance functions. The data support the use of these models for design but identify some limitations in the resistance functions.Keywords: Fiber Reinforced Plastics, Blast Loads, Full-Scale Tests, Concrete Columns, Rehabilitatio

Continuum Modeling of Ultrasonic Behavior in Fluid-Loaded Fibrous Composite Media with Applications to Ceramic and Metal Matrix Composites

Elastic wave propagation in fibrous composite materials has been the subject of numerous investigations in recent years. However, the morphology of fiber-reinforced composites can seriously complicate the calculation of their wave propagation properties. Since it is clearly not practical to attempt a solution of the completely general elastic-wave problem, most prior work [1–4] has employed various approximations to render the calculations tractable. Our own approach [5,6] to interacting continua offers an alternative procedure for modeling the response of composites, where in particular, a rational construction of the mixture momentum and constitutive-relation interaction terms is given. This theory leads to simple wave propagation equations which potentially contain the full influence of the microstructure, that is, the distribution of displacements and stresses within individual constituents of the composite

Nonlinear Normal Modes in an Intrinsic Theory of Anisotropic Beams

Accepted versio