Improvement of fire door design using experimental and numerical modelling investigations

PurposeFire door should withstand a high temperature without deforming. In the current paper, the challenges of improving the behaviour of the conventional fire door were described using various internal stiffeners in pair swinging-type fire door.Design/methodology/approachThe temperature distribution on the outside door surface was measured with distributed eight thermocouples. Subsequently the internal side was cooled with pressurized water hose jet stream of 4 bar. The transient simulation for the thermal and structure analysis was conducted using finite element modelling (FEM) with ANSYS 19. The selected cross sections during numerical simulation were double S, double C and hat omega stiffeners applied to 2.2 m and 3 m door length.FindingsDuring the FEM analysis, the maximum deformations were 7.2028, 5.4299, 5.023 cm for double S, double C and hat omega stiffeners for 2.2 m door length and 6.57, 4.26, 2.1094 cm for double S, double C and hat omega stiffeners for 3 m door length. Finally, hat omega gives more than three times reduction in the deformation of door compared to double S stiffeners which provided a reference data to the manufacturers.Research limitations/implicationsThe research limitation included the limited number of fire door tests due to the high cost of single test, and the research implication was to achieve an optimal study in fire door design.Practical implicationsAchieving the optimum design for the internal door stiffeners where the hat omega stiffener gives minimum door deformation compared to the other stiffeners was considered the practical implication. The work included two experimental fire door tests according to the standard fire test (ANSI/UL 10C – Positive Pressure of Fire Tests of Door Assemblies) for a door of 2.2 m length with double S stiffeners and a door of 3 m length with hat omega stiffeners, which achieved minimum deformation.Originality/valueThe behavior and mechanical response of door leaf were improved through using internal hat omega stiffeners under fire testing. This study was achieved using FEM in ANSYS 19 for six cases of different lengths and stiffeners for fire doors. The simulation model showed a very close agreement with the experimental results with an error of 0.651% for double S and 1.888% for hat omega.

The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China

A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.

Deformation of elastic-viscous beams by explosive load in water

Представлено аналитическое решение задачи о деформировании взрывом сосредоточенного заряда конденсированного взрывчатого вещества (ВВ) балки, материал которой чувствителен к скорости деформации. Влияние внешней среды (воды) на процесс и результаты деформирования учитывается введением присоединенной массы. Коэффициент вязкости и модуль упругости в фиксированных интервалах скоростей деформирования определяются из экспериментов. Для этих параметров, характеризующих материал балки при импульсном деформировании, получена аналитическая взаимосвязь и нижняя граница значений для коэффициента вязкости. Решение задачи найдено методом разделения переменных в определяющем уравнении движения. При этом форма упругой линии балки для каждого момента времени выбрана, исходя из требования выполнения граничных условий и принципа минимума работы деформирования. An analytical solution to the problem of deformation by an explosion of a concentrated charge of a condensed explosive (HE) of a beam, the material of which is sensitive to the rate of deformation, is presented. The influence of the external environment (water) on the process and the results of deformation is taken into account by introducing the added mass.The viscosity coefficient and the modulus of elasticity in fixed intervals of strain rates are determined from experiments. For these parameters, which characterize the material of the beam under impulse deformation, an analytical relationship and a lower limit of values for the viscosity coefficient are obtained. The solution to the problem is found by the method of separation of variables in the governing equation of motion. In this case, the shape of the elastic line of the beam for each moment of time is selected based on the requirement to fulfill the boundary conditions and the principle of minimum deformation work.

Dynamic Simulation Study on Protective Coal Pillar Width on Floor Roadway

Determination of reasonable protective coal pillar width has a great significance for the safety and stability of the coal seam working face and the surrounding structures and facilities. For studying the reasonable width of protective coal pillar, based on the platform of ABAQUS, program with the PYTHON language to make dynamic model which can simulate the dynamic changes of different width. Then the deformation law of floor roadway under different protection coal pillar width is analyzed. The finite element optimization analysis program is compiled based on MATLAB, and the minimum deformation of roadway and protective coal pillar is used as the optimization goal to make calculation for the dynamic model, and the reasonable width of protective coal pillar is proposed. Through the comparison between the simulation result and the field monitoring data, validity of the calculation result and rationality of the method are verified. The research results provide the reference for the setting of protective coal pillar for similar mining conditions.

Fuzzy C-means measurement of mass base on image features

Mass of an object is an important characteristic for quality assessment. However, in some cases, it is hard to measure the mass of objects with instruments directly. In this paper, we proposed a novel method based on Fuzzy c-means (FCM) to measure the mass of an object by analyzing the deformation degree in a grid pattern. In the spatial field, thin plate spline (TPS) algorithm was adopted to calculate the minimum deformation bending energy in order to give a quantitative analysis of the weight; In frequency domain, the Fast Fourier Transform (FFT) algorithm was used to calculate the spectrum within a deformation frequency area before and after the change of grids, from which the relationship between weight and spectrum was investigated using FCM algorithm. Two different equations evaluated by the above two methods were proposed in order to calculate the mass of an object. Both of them showed a high level of explanatory power of R2 (R2 = 0.9833 and R2 = 0.9698, respectively). The equations were then used to determine the estimated mass. Estimated and measured values were plotted against each other. A high correlation (R2 = 0.9833 and R2 = 0.9698, respectively) was found between actual and calculated mass. Finally, Bland-Altman plot was introduced to access the agreement of the calculated mass and the actual mass. The average bias was –54.408 g and –0.007 g for spatial domain method and frequency domain method, respectively. Theoretical analysis and experiments were performed to verify the effectiveness of our approaches.

Analysis of the residual stresses and deformations during the autogenous GTAW process

Purpose The gas tungsten arc welding (GTAW) process is a widely used process that produces quality weldments. But the high heat generation from the GTAW arc can cause extreme temperatures as high as 20,000°C. The residual stresses and deformations are high accordingly. One of the methods for decreasing residual stresses and deformations is to change the welding pattern. In the literature, there are not so many examples of modeling dealing with welding patterns. This paper aims to investigate the influence of welding patterns on the deformations. Design/methodology/approach In this work, back-stepping patterns and partitioning of the weld line were investigated and the distortions and residual stresses were calculated. By doing this, temperature-dependent thermophysical and thermo-mechanical material properties were used. The temperature distribution and deformation from experiments with the same welding conditions were used for validation purposes. Findings Seven different welding patterns were analyzed. There is only one pattern with a single partition. There are three patterns investigated for both two and three partitioned weldings. The minimum deformation and the optimum residual stress combination is obtained for the last pattern, which is a three partitioned and diverging pattern. Originality/value The most important aspect of this paper is that it deals with welding patterns, which is not much studied beforehand. The other important thing is that the structural part and the thermal part of the simulation were coupled mutually and validated according to experiments.

The minimum deformation retract on the wormhole spacetime

In this paper, we investigate the topology of a wormhole from the viewpoint of the theory of retracting and var-folding. We deduce the equatorial geodesics on the line element of the wormhole and discuss the minimum deformation retract related to this space. Using the Lagrangian equations we find that there is a type of minimum retraction of a wormhole with associated topology. We also extend the result to the [Formula: see text]-dimensional wormhole and show that the end limit of var-folding is 0-dimensional wormhole and obtain the relation between limit var-folding and limit retraction. We find a new application in geometric topology and astrophysics.

A high-resolution in vivo magnetic resonance imaging atlas of the human hypothalamic region

The study of the hypothalamus and its topological changes provides valuable insights into underlying physiological and pathological processes. Owing to technological limitations, however, in vivo atlases detailing hypothalamic anatomy are currently lacking in the literature. In this work we aim to overcome this shortcoming by generating a high-resolution in vivo anatomical atlas of the human hypothalamic region. A minimum deformation averaging (MDA) pipeline was employed to produce a normalized, high-resolution template from multimodal magnetic resonance imaging (MRI) datasets. This template was used to delineate hypothalamic (n = 13) and extrahypothalamic (n = 12) gray and white matter structures. The reliability of the atlas was evaluated as a measure for voxel-wise volume overlap among raters. Clinical application was demonstrated by superimposing the atlas into datasets of patients diagnosed with a hypothalamic lesion (n = 1) or undergoing hypothalamic (n = 1) and forniceal (n = 1) deep brain stimulation (DBS). The present template serves as a substrate for segmentation of brain structures, specifically those featuring low contrast. Conversely, the segmented hypothalamic atlas may inform DBS programming procedures and may be employed in volumetric studies.

A Novel Method for Mass Measurement by Quantitative Image Deformation

Mass of an object is an important characteristic for quality assessment. However, in some cases, it is hard to measure the mass of objects with instruments directly. In this paper, we proposed a novel method based on image processing to measure the mass of an object by analyzing the deformation degree in a grid pattern. In the spatial field, thin plate spline algorithm was adopted to calculate the minimum deformation bending energy in order to give a quantitative analysis of the weight; In frequency domain, the Fast Fourier Transform algorithm was used to calculate the spectrum within a deformation frequency area before and after the change of grids, from which the relationship between weight and spectrum was investigated. Two different equations evaluated by the above two methods were proposed in order to calculate the mass of an object. Both of them showed a high level of explanatory power of R 2 (R 2 =0.9833 and R 2 =0.9698, respectively). The equations were then used to determine the estimated mass. Estimated and measured values were plotted against each other. A high correlation (R 2 =0.9833 and R 2 =0.9698, respectively) was found between actual and calculated mass. Finally, Bland-Altman plot was introduced to access the agreement of the calculated mass and the actual mass. The average bias was -54.408g and -0.007g for spatial domain method and frequency domain method, respectively. Theoretical analysis and experiments were performed to verify the effectiveness of our approaches.

Quantifying Heterogeneity According to Deformation of the U937 Monocytes and U937-Differentiated Macrophages Using 3D Carbon Dielectrophoresis in Microfluidics

A variety of force fields have thus far been demonstrated to investigate electromechanical properties of cells in a microfluidic platform which, however, are mostly based on fluid shear stress and may potentially cause irreversible cell damage. This work presents dielectric movement and deformation measurements of U937 monocytes and U937-differentiated macrophages in a low conductive medium inside a 3D carbon electrode array. Here, monocytes exhibited a crossover frequency around 150 kHz and presented maximum deformation index at 400 kHz and minimum deformation index at 1 MHz frequencies at 20 Vpeak-peak. Although macrophages were differentiated from monocytes, their crossover frequency was lower than 50 kHz at 10 Vpeak-peak. The change of the deformation index for macrophages was more constant and lower than the monocyte cells. Both dielectric mobility and deformation spectra revealed significant differences between the dielectric responses of U937 monocytes and U937-differentiated macrophages, which share the same origin. This method can be used for label-free, specific, and sensitive single-cell characterization. Besides, damage of the cells by aggressive shear forces can, hence, be eliminated and cells can be used for downstream analysis. Our results showed that dielectric mobility and deformation have a great potential as an electromechanical biomarker to reliably characterize and distinguish differentiated cell populations from their progenitors.