Comparative Analysis of Structure with and without Seismic Load

Engineers are mostly adopting complex non-linear methods to research multi-storey residential apartment structure to withstand earthquake forces. This paper uses much simpler Equivalent Static method to analyse G+5 storey structure to repel earthquake forces using Staad pro software. The seismic analysis is further compared with non-seismic analysis of an equivalent structure using dead load + super load combination. it had been observed that the seismic results obtained consisted of significantly increased maximum moments and shear forces than the non-seismic analysis From past earthquakes it is proved that many of structure ar completely or partly broken because of earthquake. So, it’s a necessity to figure out unstable responses of such structures. The main aim of the present work is to make a comparative study of seismic and non-Seismic structure. The analysis was performed as per the specification of IS codes IS 1893, IS 875, IS 456:2000.

The Effect of Fixing Method on the Result of Ultrasonic Infrared Thermography Testing

Considering the influence of the fixing method of the component in the system on its results in ultrasonic infrared thermography testing, the detection experiments of the cracked plat structure with fixing at one end and fixing at two ends are carried out through different fixing methods of the equivalent structure. The results show that for the same structure to be detected, the more the bounds are fixed, the more the degrees of freedom are restricted, the less ultrasonic energy is dissipated during the inspection process, and the better the inspection effect. The work has positive significance for the selection of detection parameters in ultrasonic infrared thermography testing, helpful to provide some references for it.

Mechanical Performance Evaluation of the Al-Mg-Si-(Cu) Aluminum Alloys after Transient Thermal Shock through an Novel Equivalent Structure Design and Finite Element Modeling

In this paper, the microstructure evolution and mechanical performance of the Al-Mg-Si-(Cu) aluminum alloy after transient thermal shock were investigated through experimental tests and finite element simulations. A novel equivalent structure was designed as a typical case in which one side of the plate was welded therefore the other side was thermally shocked with different temperature distribution and duration. The temperature gradient which influences most importantly the mechanical properties was simulated and experimentally verified. Through cutting layers and tensile testing, the mechanical response and material constitutive relation were obtained for each layer. Gurson-Tvergaard-Needlemen (GTN) damage parameters of these samples under large strains were then obtained by the Swift law inverse analysis approach. By sorting the whole welded joint into multi-material composed structure and introducing the obtained material constitutive relation and damage parameters, tensile properties were precisely predicted for typical types of weld joint such as butt, corner, and lap joints. The results show that precipitate coarsening, phase transformation from β″ phase to Q′ phase, and dissolving in the temperature range of 243.3–466.3 °C during the thermal shock induced a serious deterioration of the mechanical properties. The highest reduction of the ultimate tensile strength (UTS) and yield strength (YS) would be 38.6% and 57.4% respectively. By comparing the simulated and experimentally obtained force-displacement curves, the error for the above prediction method was evaluated to be less than 8.1%, indicating the proposed method being effective and reliable.

Dorsal Horn Pain Mechanisms

The spinal dorsal horn and its equivalent structure in the brainstem constitute the first sites of synaptic integration in the pain pathway. A huge body of literature exists on alterations in spinal nociceptive signal processing that contribute to the generation of exaggerated pain states and hence to what is generally known as “central sensitization.” Such mechanisms include changes in synaptic efficacy or neuronal excitability, which can be evoked by intense nociceptive stimulation or by inflammatory or neuropathic insults. Some of these changes cause alterations in the functional organization of dorsal horn sensory circuits, leading to abnormal pathological pain sensations. This article reviews the present state of this knowledge. It does not cover the contributions of astrocytes and microglia in detail as their functions are the subject of a separate chapter.

Grain and bedform roughness properties isolated from gravel-patch DEMs

Remote sensing of gravel-bed patches and resulting high-resolution digital elevation models (DEMs) allow for the identification of various spatial scales of surface roughness. Thus far, dimensions relating to grain and bedform roughness scales have been determined using semivariograms or equivalent structure/autocorrelation functions. However, it is difficult to clearly differentiate roughness scales and separate analysis of roughness properties is not possible. This study examines the use of moving-window detrending on gravel-patch DEMs for isolating grain and bedform roughness and their respective topographic signatures. An extensive dataset of water-worked gravel surfaces collected in both laboratory and field environments is used. The measured bed topography is separated into two distinct DEMs: one representing grains, the other representing bedforms, and roughness properties are determined separately for grain and bedform DEMs. The results show that both roughness scales are controlled by the size of the coarse sediment forming the bed surface, with positive linear relationships connecting bed composition and vertical roughness. Coarse sediment is controlling bedform development by forming humps on the surface, in the lee of which finer sediment is sheltered. We present synthesis relationships connecting vertical roughness of gravel patches to the vertical roughness of grains and bedforms.

Dynamic analysis of finger seal in the complex working state

With the development of aero-engine industry technology, the operating conditions for finger seal become more horrible, including that high temperature, assembly type of finger seal, rotor tilt, and impact of rotor coexist. Unfortunately, the coupled effect on the dynamic performance of finger seal is not studied in previous works for the dynamic of finger seal. In this paper, the parameters of equivalent dynamic model for finger seal, including the equivalent structure stiffness of finger stick, the contact stiffness between finger stick and rotor, the friction heat between finger boot and rotor and the rotor displacement excitation, are corrected when the coupled effect of rotor tilt, assembly condition, temperature, and impact are considered. In addition, the distributed mass equivalent dynamic model is developed for considering the complex working conditions (including rotor tilt, assembly condition, temperature effect, and impact effect). Based on this model, the dynamic performance of finger seal in the complex working state is analyzed, and the influence of the complex working state on the dynamic performance is also studied. The results indicate that effect of the complex working state on the leakage performance and wear performance of finger seal is complex. The work in this paper demonstrates the necessity of considering the complex working conditions in the analysis of the dynamic performance of finger seal.