Dynamic behavior of a smart device on a surface subjected to earthquake motion

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144310/1/eqe3048_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144310/2/eqe3048.pd

Adenocarcinoma of the appendix presenting as bilateral ureteric obstruction

<p>Abstract</p> <p>Background</p> <p>Adenocarcinoma of the vermiform appendix is a rare neoplasm of the gastrointestinal tract. Presentation mimics acute appendicitis, but right iliac fossa mass and intestinal obstruction have also been reported. These presentations reflect various stages of a locally expanding tumour causing luminal obstruction of appendix. The investigation and subsequent management with a review of the literature is presented.</p> <p>Case presentation</p> <p>We report a case of appendicular adenocarcinoma found unexpectedly in a 43 year old male who presented with urinary symptoms. Cystoscopy and uretero-renoscopy showed normal bladder but external compression of the ureters and therefore bilateral stents were inserted. CT scan showed a caecal mass. After colonoscopy, that showed external compression, and diagnostic laparoscopy the patient underwent right hemicolectomy. Histopathology revealed well differentiated adenocarcinoma with signet ring morphology with multiple lymph node involvement. The patient was referred for chemotherapy where he received infusional 5 fluorouracil but died 7 months after surgery.</p> <p>Conclusion</p> <p>Patients with atypical manifestations related to right lower abdominal quadrant should be thoroughly investigated with an open mind. Every attempt should be made to make a precise diagnosis through all the available means to direct the treatment along correct lines.</p

Panel Zone Yielding In Steel Moment Connections

The effect of panel zone yielding on the behavior of fully-restrained steel moment connections is investigated. The evolution of seismic design provisions for steel panel zones is discussed and experimental evidence is presented that suggests that an excessively weak panel zone could be detrimental to connection behavior. The observed behavior is explained through detailed inelastic finite element analyses. Based on the experimental and analytical evidence, modifications to existing seismic provisions for steel panel zones are proposed that make the provisions conceptually more transparent

Inelastic Dynamic Behavior Of Hybrid Coupled Walls

This paper presents an investigation of the seismic behavior of hybrid coupled wall systems, in which steel beams are used to couple reinforced concrete shear walls. System response is studied using transient finite element analyses that account for the effect of concrete cracking, crushing, and steel yielding. Shear stresses in the concrete constitutive model are handled separately from normal stresses, which allows concrete to undergo high shear deformations without causing premature concrete crushing in the model. The developed finite element models are validated through comparisons with more refined models and test data. Suites of analyses are conducted to investigate pertinent parameters including hazard level, earthquake record scaling, dynamic base shear magnification, interstory drift, shear distortion, coupling beam plastic rotation, and wall rotation. The analyses show that hybrid coupled walls are particularly well suited for use in regions of high seismic risk

Crack velocity-dependent dynamic tensile behavior of concrete

Experiments have consistently shown that the tensile strength of concrete increases with increasing strain rate. The reasons for this phenomenon are not yet well understood and several hypotheses have been proposed in the past to explain it. This study offers additional insight through the application of dynamic fracture mechanics. The relationship between crack velocity and strain rate of concrete is first investigated using a cohesive zone model and fitted to available experimental data. The obtained relationship is then implemented into two different versions of crack-speed dependent dynamic fracture models. Both models show that computed strength versus strain rate responses compare favorably to well-established test data, suggesting that strain rate sensitivity is strongly associated with the characteristics of dynamic crack growth and inertial effects at the boundaries of the crack. A constitutive modeling scheme that incorporates the obtained dynamic fracture models into a meso-mechanical model is also proposed to predict stress-strain behavior of concrete under dynamic tensile loading. Comparisons between model predictions and published experimental data are provided to show the accuracy of the proposed framework

Nonlinear Static And Dynamic Analyses Of A Low-Rise Steel Building

Nonlinear static and nonlinear dynamic procedures in the Guidelines for the Seismic Rehabilitation of Buildings (FEMA-273 1997) are used to analyze an existing fourstory steel moment frame building previously damaged in the Northridge earthquake. Results from both types of analyses are compared with the objective of exercising and evaluating the FEMA-273 (1997) procedures for low-rise steel moment frames. Copyright 2004 ASCE

Tension Flange Effective Width In Reinforced Concrete Shear Walls

The ACI318-02 specification suggests a simple expression that is a function of story height for estimating tension flange effective width In flanged reinforced concrete (RC) shear walls. Other influential variables such as drift level, wall width, and the level of axial load are not addressed in the ACI expression. A detailed finite element model is used to investigate the effect of these parameters on the tension flange effective width. The finite element model accounts for nonlinear steel and concrete behavior and is validated through comparisons to test data. The analytical results show that the tension flange effective width is strongly dependent on all the variables investigated. Implications of the presented data regarding existing guidelines are discussed and provisions are suggested that are suitable for implementation in performance- based design criteria

Capturing the strain hardening and softening responses of cementitious composites subjected to impact loading

Ultra-high performance fiber reinforced concrete (UHP-FRC) is a type of cementitious composite that has extended hardening and softening responses when subjected to tension. The length of the tensile loading regime complicates the development of test setups that can capture the full tensile response at high strain rates. To address this challenge, analytical and finite element modeling are used to propose modifications to an existing test set up to enable it to conduct accurate and practical testing of UHP-FRC specimens in direct tension, under high strain rate. The test device employs suddenly released strain energy to generate an impact pulse and a sufficiently long transmitter bar to channel the signal and measure it. Tests conducted on UHP-FRC specimens at strain rates of 90-145 1/s show that, under increasing strain rates, the material maintains its strain capacity and has highly enhanced strain dissipation capacity, making it particularly well suited for blast and impact applications

Stress-resultant plasticity for frame structures

Two versions of a bounding surface plasticity model implemented in stress-resultant space and applicable to the analysis of steel, reinforced concrete, or composite beam-columns are discussed. One is a two-surface model appropriate for steel members with a finite elastic region. The second, which is developed for reinforced concrete and composite steel-concrete members, employs a single outer bounding surface with an infinitely small loading surface that is degenerated to a point. Plasticity-based assumptions employed in the formulation of these models are reviewed and predicted plastic flow directions are evaluated against data from more fundamental fiber-type analyses of the beam-column cross sections. Results of these comparisons support the use of Mroz\u27s kinematic rule in stress-resultant space and lead to recommended improvements in the bounding surface formulation

Pushover Of Hybrid Coupled Walls. Ii: Analysis And Behavior

Presented are the results of nonlinear pushover analyses of the hybrid coupled wall (HCW) prototypes designed and discussed in a companion paper. The objectives of the analyses are (1) to study the effect of the coupling ratio on system response; and (2) to evaluate existing design guidelines for HCWs. The discussion addresses target displacements, displacement profile, base shear, wall reactions, story drifts over the height, wall plastic rotations, shear distortions, coupling beam rotations, wall-beam connection response, crack patterns, concrete crushing at critical locations, and system overstrength. The suitability of HCWs for use in regions of high seismic risk is discussed