Pitch-catch UGW-based multiple damage inference: a heterogeneous graph interpretation

Ultrasonic guided waves (UGWs) have been extensively utilized in nondestructive testing (NDT) and structural health monitoring (SHM) for detection and real-time monitoring of structural defects. By implementing multiple piezoelectric sensors onto a plane of the target structure to form a sensor network, damages within the sensing range can be detected or even visualized through a pitch-catch configuration. On the other hand, deep learning (DL) techniques have recently been widely used to aid UGW-based SHM when the waveform is over complicated to extract a specific mode of interest due to irregular structure or boundary reflections. However, not too much research work has been conducted to thoroughly combine sensor networks with DL. Existing research using DL approaches is mainly used to train and interpret waveforms from isolated sensor pairs. The topological structure of sensor layout and sensor-damagerelative positions are hardly considered in the data-driven process. Motivated by these concerns, this study offers a first-of-its-kindperspective to interpret UGW data collected from a sensor network by mapping the physical sensor-damage layout into a graph, in which sensors and potential damages serve as graph vertices bearing heterogenous properties upon coming to UGWs and the process of UGW transmission between sensors are encapsulated as wavelike messagepassing between the vertices. A novel physics-informedend-to-end GNN model, named as WaveNet, was exquisitely and meticulously developed. By utilizing wave information and topological structure, WaveNet enables inference of multiple damages in terms of severity and location with satisfactory accuracy, even when the waveforms are chaotic and the sensor arrangement is different at the training and testing stages. More importantly, beyond the SHM scenario, the present study is expected to enlighten new thinking on interconnecting physical wave propagation with virtual messaging passing in neural networks.

The Effect of Polymerization Temperature on the Properties of Polyvinyl Fluoride Polymerization in Supercritical Carbon Dioxide

The ongoing search for environmentally friendlier alternative to the organic solvents used in chemical processes has led to the development of technologies based on supercritical carbon dioxide (scCO2), which is non-flammable, non-toxic and relatively inert fluid. Polymer chemistry does not escape this trend. Fluoropolymers prepared in scCO2 have many special properties, which are different from fluoropolymers that use water as the reaction medium, this paper studies the effect of polymerization temperature on polyvinyl fluoride polymerization in supercritical carbon dioxide. The results show that as the polymerization temperature increases, the intrinsic viscosity and shear viscosity of the polymer gradually decreases; at the same time, the increasing of polymerization temperature leads to higher proportion of irregular structure of the polymer, which causes lower melting point and lower crystallinity, and the film prepared by the resin also exhibits a higher visible light transmittance. The above results show that the resin polymerized in supercritical carbon dioxide can impart better performance to conventional polymerization, which expands the potential application fields of the resin.

Analytical Design of Irregular Buildings founded on soft soil

In modern day, due to the need of unique architectural appearance or aesthetics of building, irregularities in mass, stiffness and symmetry may get disturbed, making the whole structure vulnerable to certain damages either minor or major. Some of the functional considerations of these structures are use of ground floor as car parking in residential buildings, use of basement as car parking in malls, etc. Seismic range is one the most important factors to be considered to analyze any irregular structure. In this study, the design of different G+6 structures having vertical regularity was done. These irregular structure models were compared with a regular G+6 structure having similar properties as other structures. For the designing and analysis of these structures, use of StaadPro software was done. It is one of the most used software, whenever it comes to the digital analysis of any structure. Different types of Vertical irregularities like mass irregularity, Vertical Setback Irregularity, Stiffness Irregularity (Discontinuous Column, Middle weak storey and Bottom Weak Storey) were considered for the analysis. The Seismic Zone for the structure is considered to be Delhi (Seismic Zone IV) with a Seismic Factor of 0.24. All the model structures were compared for the parameters of their Storey Drift and Storey Displacement. For irregular buildings though, certain damages/fatigue may be observed in some structures but the structures will not fail and will be serviceable for a long time with proper care. It was observed that the structures with stiffness irregularity showed the most increase in storey displacement and storey drift values.

Comparative analysis of vertical irregularities on high rise structure considering various parameters

Now, every day tall constructing structures constructed around the goal of residential and industrial cause etc. Layout of tall buildings both earthquake as well as wind loads got to be take into considered. An irregular structure, failure of structure starts at a point of its weakness and those weaknesses comesups withs separation of mass, stiffness and geometry of that models. The structures having this kinds of discontinuity are called Irregular structures. (H, J, & darshan, 2017) [2]. For example,Structures with the soft storey were the foremost remarkable fallen structures. Therefore, the impact of vertical alignment within the seismic structure of buildings is very significant. The changes in durability and size provide powerful features of those structures that are completely different from the standard structure. For this present evaluation ‘ETABS’ software package is employed. All Reinforced Concrete structural elements are follows as per ‘IS 456:2000 (Plane and Reinforce Concrete-Code of Practice, Bureau of Indian Standard)’. Seismic load follows with respect to IS 1893:2016 along with self-weight of modelles for analysis of the structure. Here 2 kinds of buildings of (G+15) were created one is regular structure and alternative one Mass irregular. To observe, Effect of lateral in both buildings using Seismic load and to check the results,most of maximum displacement for various models and various parameters.

Comparison of Analysis and Design of Regular and Irregular Configuration of Multi Story Building in Seismic Zones

This paper is concerned with the effects of various vertical irregularities on the seismic response of a structure. The objective of the project is to carry out Response spectrum analysis (RSA) and Time history Analysis (THA) of vertically irregular RC building frames and to carry out the ductility based design using IS 13920 corresponding to Equivalent static analysis and Time history analysis. Comparison of the results of analysis and design of irregular structures with regular structure was done. The scope of the project also includes the evaluation of response of structures subjected to high, low and intermediate frequency content earthquakes using Time history analysis. Three types of irregularities namely mass irregularity, stiffness irregularity and vertical geometry irregularity were considered. According to our observation, the storey shear force was found to be maximum for the first storey and it decreases to minimum in the top storey in all cases. The mass irregular structures were observed to experience larger base shear than similar regular structures. The stiffness irregular structure experienced lesser base shear and has larger inter-storey drifts. The absolute displacements obtained from time history analysis of geometry irregular structure at respective nodes were found to be greater than that in case of regular structure for upper stories but gradually as we moved to lower stories displacements in both structures tended to converge. . Lower stiffness results in higher displacements of upper stories. In case of a mass irregular structure, time history analysis gives slightly higher displacement for upper stories than that in regular structures whereas as we move down lower stories show higher displacements as compared to that in regular structures. When time history analysis was done for regular as well as stiffness irregular structure, it was found that displacements of upper stories did not vary much from each other but as we moved down to lower stories the absolute displacement in case of soft storey were higher compared to respective stories in regular structure. Tall structures were found to have low natural frequency hence their response was found to be maximum in a low frequency earthquake. It is because low natural frequency of tall structures subjected to low frequency earthquake leads to resonance resulting in larger displacements. If a high rise structure (low natural frequency)is subjected to high frequency ground motion then it results in small displacements. Similarly, if a low rise structure (high natural frequency) is subjected to high frequency ground motion it results in larger displacements whereas small displacements occur when the high rise structure is subjected to low frequency ground motion.

Seismic Response of Vertical Irregular Structures in Setback and Stepped Buildings

Vertical irregular buildings are frequently constructed across the globe for functional as well as aesthetic purpose. However post-earthquake reconnaissance survey reports revealed high seismic vulnerability of the building with vertical irregularities. Consequently it is very important to explore the reason behind the high seismic vulnerability and the poor performance of irregular structures during the earthquake. A humble effort is under taken considering several case studies comprising different configuration of vertical irregular structures, so as to comprehend the seismic behavior of vertical irregular structure using response spectrum and pushover analysis has been attempted in finite element software ETABS 16.2.1 version. The results of the analysis indicate the irregular structures have ample chance of higher stress concentration as well as higher displacement demand at the vicinity of irregularity. Member strength enhancement at the vicinity of vertical irregularity may improve the overall seismic performance of the building. Also, this research checks the adequacy of fundamental mode properties for the quantification of vertical irregularity. Furthermore, pushover analysis has been done to observe the hinge formation pattern and also the plastic hinge rotation for observing the performance level of building.

Structure Optimization of a High-Temperature Oxygen-Membrane Module Using Finite Element Analysis

The oxygen transport membrane (OTM) is a high-density ion-conducting ceramic membrane that selectively transfers oxygen ions and electrons through the pressure differential across its layers. It can operate at more than 800 °C and serves as an economical method for gas separation. However, it is difficult to predict the material properties of the OTM through experiments or analyses because its structure contains pores and depends on the characteristics of the ceramic composite. In addition, the transmittance of porous ceramic materials fluctuates strongly owing to their irregular structure and arbitrary shape, making it difficult to design such materials using conventional methods. This study analyzes the structural weakness of an OTM using CAE software (ANSYS Inc., Pittsburgh, PA, USA). To enhance the structural strength, a structurally optimized design of the OTM was proposed by identifying the relevant geometric parameters.