Performance evaluation of gradient TPMS structure coupled with heat pipe for high-power chip heat sink

In this study, the seismic behavior of steel concrete composite buildings in a specific region was investigated. For this purpose, 5-, 10-, 15- and 20-storey composite moment-resisting framed structures were designed. Moment-resisting composite framed structures are modeled with concrete-filled steel tube columns and designed and modeled using composite beams. The buildings are designed according to ÇYTHYE-2016 and TBEC-2018 regulations at design levels with high ductility. In the design of the designed structures, the peak ground acceleration value is 0.79 g, and the design ground is planned as ZE class. SeismoStruct software was used for the design and performance evaluation of the structures. During the performance evaluations of the structures, nonlinear static pushover and incremental dynamic analyzes were used. Uniform and triangular load distributions are adopted in the static pushover analysis and 16 earthquake ground motions are used in the incremental dynamic analysis. Evaluation of the effect of the number of stories on the earthquake behavior of composite moment-resisting framed structures was investigated using the non-linear analyzes mentioned. Accordingly, lateral response, overstrength factors, ductility, and dynamic behavior factor values for composite frame structures were calculated and presented using the relevant analysis results. It has been calculated that the behavior factor of all moment-resisting composite framed structures can perform well above the design assumptions, whereas moment-resistant composite framed structures absorb seismic energy by using inelastic deformations. Ductility is almost 30% higher than the design assumption for international standards. As a result, it was concluded that these structures could continue to serve theoretically.

Experimental and numerical study on temperature control performance of phase change material heat sink

Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

With the development of information technology, the heating power of data transmission equipment (mobile phones, notebook computers, data center processors, etc) continues to rise, and the high temperature failure has become a major cause of equipment damage. At present, the heat flux of high-power chips has reached 2 ´ 106 W/m2. Therefore, the traditional single-phase heat transfer is unable to meet the heat dissipation requirements of new data equipment, and more efficient heat exchange methods are urgently needed to ensure the normal operation of the equipment. As a highly efficient phase change heat transfer element, the thin plate grooved heat pipe is researched in the order of millimeters or even micrometers. Therefore, flat grooved heat pipes simultaneously satisfy the heat dissipation and packaging requirements of high power data transmission equipment, and thus have been extensively studied. In the present study, the phase change characteristics and heat transfer performance of flat-plate heat pipes with rectangular grooves were experimentally studied. Each micro heat pipe test section consisted of twenty parallel grooves with the same total length of 90 mm. The cross-sectional area of G-400 heat pipe and G-800 heat pipe were 400 μm ´ 400 μm and 800 μm ´ 800 μm, respectively. The evaporation section, adiabatic section and condensation section had the same size of 30 mm, and vapor space height was equal to 3.6 mm. The flat-plate was sealed on its upper face with transparent plate, and the phase change phenomenon in the grooves could be observed. A high speed camera was used to visualize the phase change phenomenon in evaporation and condensation regimes. The experiments were carried out with the same cooling water temperature of 30°C under the conditions comprising the heat power range of 18–90 W and filling ratio of 150%–400%, respectively. In order to systematically investigate the performance of flat heat pipes with different dimensions of micro grooves, the analysis was focused on the heat resistance and phase change phenomenon in evaporation section and condensation section. The results showed that the heat pipe with wide grooves was able to maintain stable heat transfer performance at higher heat power, while heat pipes with narrow grooves would dry out at lower heat power. The optimal liquid filling rate of G-400 heat pipe was 400%, and the optimal liquid filling ratio of G-800 heat pipe was 150%. Furthermore, the heat transfer in the evaporation section of flat heat pipe with narrow grooves was mainly dominated by liquid film evaporation. Comparatively, the heat transfer phenomenon in the evaporation section of a heat pipe with wide grooves was affected by the liquid filling ratio. The liquid film evaporation was the main solution at low liquid filling ratio, and continuous bubble behavior was visualized in high filling ratio. In addition, the phase change behaviors in the condensation section of rectangular-grooved flat heat pipe not only occured at the gas-liquid interface, but also had droplet condensation phenomenon on the top surface of the groove rib. The cycle of condensation consisted of three stages: Droplet growth, droplet coalescence, and droplet department.

The rapid progress of advanced manufacturing, multidisciplinary integration and artificial intelligence has ushered in a new era of technological development in the design of lightweight, well-integrated, multifunctional, intelligent, flexible and biomimetic materials and structures. The traditional approach in structural research poses several intrinsic limitations on the practical performance of devices and instruments in harsh industrial environments, due to factors such as the disconnection between structural design and manufacturing, low efficiency in the manufacture of complex structures, reduced actual mechanical integrity and reliability of manufactured structures compared to the theoretical values obtained from structural design, insufficient level of multifunctional structural integration, and excessive economic cost. In addition, the advanced materials and structures incorporated in industrial equipment often need to withstand extreme service environments, and it is increasingly important to further integrate the design, manufacture, function, performance evaluation and industrial application of advanced structures, to provide the theoretical and technical bases for optimizing their fabrication. In view of the above, the authors propose a new research paradigm of “mechanostructures,” which aims to achieve target mechanical responses of structures, devices and equipment in extreme service environments by integrating their structural design, manufacturing and performance evaluation. By designing novel structures based on desired static and dynamic mechanical responses and considering the mechanical behavior throughout the whole deformation process, the new field of “mechanostructures” pursues an application-oriented structural design approach. As a typical example of mechanostructures, lightweight multifunctional lattice structures with high stiffness, strength, impact resistance, energy absorption capacity, shock wave attenuation and noise reduction show great potential for applications in aerospace, transportation, defense, biomedical, energy, machinery, equipment and other industrial fields. In this respect, the mechanical design of lattice metastructures inspired by polycrystalline microstructures is presented, starting with a discussion on typical mechanical properties and multifunctional performance conflicts, and demonstrating the scientific merits of “mechanostructures” based on the innovative structural design, manipulation of the multifunctional mechanical properties, and elaboration of the underlying physical mechanisms.

Experimental investigation on the heat transfer performance of a flat parallel flow heat pipe

Due to its outstanding performance and merits, Self-Consolidating Concrete (SCC) has attracted a wide attention from scientists, researchers and engineers all over the world. At present, many research activities have been conducted in developing and evaluating SCC and its related technologies. However, existing performance evaluation methods of are mostly limited in the field of material, while structure performance evaluation methods of SCC are rarely reported. As we all known, the lifetime of the SCC structure is mainly subject to its material, structural and durability performances as a whole. Undoubtedly, it is crucial for us to study and develop a sound structural and durability performance evaluation method to complement the existing material performance evaluation methods. As such, the structural and durability performance evaluation method of SCC was studied in this paper.

In this study we developed an integrated precast concrete decks for a rapid construction. The structural performance in the integrated precast bridge decks is evaluated by real-scale test bed and detailed finite element analyses. The numerical analysis results were compared with the experimental data from a real-scaled single-span precast/prestressed concrete bridge decks under truck loading. Parametric studies are focused on the various effects of external loads on the structural behavior for different locations and measuring points on the precast bridge decks. The assessment in this study indicates that the integrated precast bridge decks show an excellent structural performance as expected.

Seismic performance evaluation of a fire-exposed historical structure using an updated finite element model

Regenerative architecture arises as an approach that goes beyond the idea of sustainable buildings. More than a deep relationship with the environment it intends to promotes living systems regeneration through a full understanding of the location in order to design regenerative structures. In this context, it sets up a new concept in architecture, requiring specific knowledge that must be inserted in academic education. Such knowledge is interdisciplinary, geometry being a field of specific interest. Geometry supports the analysis of the activity patterns that shape local forms, to understand how these patterns influence the regeneration process; the performance evaluation of structures on the thermal conditioning of the projected building; the formal proposal of structures in a generative process, achieved through parametric techniques of digital representation. In this paper, we discuss the concepts necessary for the insertion of regenerative design in architecture and present some initiatives developed in training and professional contexts.

Ignatius Christiawan, in this paper explain that In effort fulfill requirement the well building infrastructure, safety of building user such as building avalanche damage as result of earthquake is principal priority. Due to user safety to building avalanche as result of earthquake then it was issued the Procedure of Earthquake Endurance Planning SNI 03-1726-2003 that regulates of planning, build or operates a building. Problem emerge at the building which have the old regulation plan, so it was need evaluation based on the new regulation. Evaluation is conducted at the 3 floor laboratory and lecturing building. Research was focused on performance evaluation of structure on existing condition relate at regulation of the Procedure of Concrete Structure Calculation for the SNI 2847-2002, application for earthquake based on SNI-1726-2002. SAP 2000 is used to analyze the pushover to obtain the building ductility value and the reduction factor value (R) from the building. The result of material test was obtained fo’ existing 17 Mpa and fy existing 390 Mpa. The result of structure performance evaluation was obtained the service limit performance and the building unlimited performance fulfilling condition SNI – 1726 – 2002. Keywords: plan earthquake, evaluation, safety.

Graphene nanosheet/silicone composite with enhanced thermal conductivity and its application in heat dissipation of high-power light-emitting diodes

The paper presents a review of testing methods, a proposal for classifying the strategies, and tools applied in the monitoring of concrete bridges, the required consistent taxonomy of defects, and also the degradation mechanisms that are typical for such structures. Two main strategies of bridge monitoring are distinguished and described: inspection‐based monitoring and device‐based monitoring. The basic functional components of both types of monitoring systems are also presented. Monitoring methods, including nondestructive and semi‐destructive techniques, as well as various types of sensors based on physical, chemical, and biological technologies, are discussed and classified. The general rules of the implementation and operation of bridge monitoring systems are presented while taking into account the results of international research projects and contemporary practical experience. The considered issues are related to the fib Model Code 2020 (MC2020), which focuses on the evaluation of structural performance and which is assisted by monitoring and testing.

In the past decades, many shield tunnels have been constructed for use in important lifeline infrastructure such as roads, railways, water supply systems and sewers. A good performance of the tunnel requires appropriate maintenance associated with a substantial cost; therefore, a rational maintenance approach is required. Preventive maintenance has been previously applied in an efficient and effective manner. However, the evaluation of structural performance, as well as the choosing an appropriate maintenance management strategy, is still a challenge. This paper proposes a maintenance framework for the shield tunnel. Structural performance and life cycle cost are evaluated as the major indicators accounting for the major deterioration (e.g. steel corrosion, cracking, etc.). The structural performance-based strength cost for an expected service time is used as the criterion to select a rational maintenance plan. Furthermore, structural reliability analysis is performed to validate the proposed framework and investigate the influence of deterioration model. The proposed framework was successfully applied to the maintenance of a trunk sewerage pipe for choosing a rational maintenance plan.

ABSTRACTSaving energy consumed in buildings has become an important factor in design. Thus, the aim of this research is to assess the thermal and structural performance of different types of concrete slabs using real simulation for heat transferred from solar radiation, and from difference between indoor and outdoor temperatures in the existence of dead and imposed loads. Three types of slabs were examined: normal, voided and foamed concrete. Moreover, the effect of slab end conditions was investigated. Thermal analysis was performed for each slab type considering summer and winter weather of Egypt. In this analysis, the heat transferred through each slab was calculated, and hence the ability of each type to maintain the indoor temperature could be determined. The non-uniform distribution of temperature along the thickness of each slab type was used through structural analysis to examine the performance of the considered slabs under the effect of thermal actions and static loads. Both voided and foamed concrete slabs maintained successfully the indoor temperature from being affected by the climatic conditions; whereas, the best from a structural point of view was in favor of voided slabs as clarified through this research.