Numerical Analysis Software Research Articles

Influence of Loading Peak and Loading Rate on Twin Fibers Pullout Test of Concrete Matrix

Numerical analysis software based on linear finnite element method and statistical damage theory concrete material has been adopted in this study. Dynamic numerical model of twin fibers pullout test of concrete matrix have been created by considering the meso-heterogeneity of concrete material. The whole process from micro-cracks initiation, propagation to crack penetration has been simulated. The influence of stress wave loading peak and loading rate on twin fibers pull-out test of concrete matrix under dynamic load has, therefore, been scrutinized. Results show that loading rate has effect on failure mode and crack propagation along interface of the twin fibers pull-out specimens. With increasing loading rates, the rate of interface crack propagation and damage area increase either.

Progressive failure and friction motion characteristics of contact surface of composite rock mass

The structural planes existing in natural rock mass can control the failure process of rock mass. Based on the progressive response-stability failure process of a single fracture interface, the relationship between progressive response and material failure of composite rock mass is discussed. The method of friction contact plane analysis in PANDAS numerical analysis software is applied to explore the correlation between the movement and mechanical properties of composite rock mass under external forces. The motion index is mainly represented by the sliding speed and distance of the contact surface, while the mechanical properties are mainly explained by the normal contact force, the friction of the contact surface, the friction coefficient and the material damage. The relationship between these six variables illustrates the progressive response relationship during the movement of the composite rock mass. Based on the static and progressive characteristics of the progressive response process of deep rock mass engineering, the failure evolution law and energy dissipation law of composite rock mass loading process and the synergistic failure characteristics of composite rock mass are discussed. The scientific problems that need to be studied in the structure, deformation and failure of deep rock mass are put forward. The reference is provided for the failure law of fractured rock mass in water inrush process under the influence of mining, as well as fault plate material and the study of mechanical state of rock mass in fault fracture zone.

Experimental analysis of compressive behavior of E-Glass fiber reinforced IPN (vinyl ester/polyurethane) composite pipes

The manuscript discusses about the effect of compressive load on the E-Glass fiber reinforced interpenetrating polymer networks (IPNs). In this work, a series of combination of vinyl ester (VER) loaded polyurethane (PU) IPNs have been taken as the matrix material with the E-Glass reinforcement, with the loading of 0%, 10%, 20%, 30%, 40%, 50% PU respectively. Besides hand-layup technique was used to fabricate the cylindrical shells in order to get the final shape of the IPN composite pipe. Simultaneously to validate the compressive strength behavior of the IPN composite pipe, experimental analysis was carried out as per the ASTM D695 standard at normal room temperature to extract compressive strength value of the PU loaded IPN composite pipes. During this test, it was observed that physical strength of the composite pipes reduces gradually as much as PU addition into the IPN composite pipe increases. Surprisingly, another important notification was that, the geometric structure of the composite pipes is not affected as like as the crushing observed on the pure VER pipe. As much as loading of the PU into the IPN, increases the structural integrity of the composite pipes in outstanding (retains structural ability) manner. Further the experimental analysis values are validated with numerical analysis software ANSYS, obtained values and numerical values are shown good agreement each other.

BIM-to-IGA: A fully automatic design-through-analysis workflow for segmented tunnel linings

Both planning and design phase of large infrastructural project require analysis, modelling, visualization, and numerical analysis. To perform these tasks, different tools such as Building Information Modelling (BIM) and numerical analysis software are commonly employed. However, in current tunnel engineering practice, there are no systematic solutions for the exchange between design and analysis models, and these tasks usually involve manual and error-prone model generation, setup and update. In this paper, focussing on tunnelling engineering, we demonstrate a systematic and versatile approach to efficiently generate a tunnel design and analyse the lining in different practical scenarios. To this end, a BIM-based approach is developed, which connects a user-friendly industry-standard BIM software with effective simulation tools for high-performance computing. A fully automatized design-through-analysis workflow solution for segmented tunnel lining is developed based on a fully parametric design model and an isogeometric analysis software, connected through an interface implemented with a Revit plugin. The IGA-Revit interface implements a reconstruction algorithm based on sweeping teachnique to construct trivariate NURBS lining segment geometry, which avoids the burden to deal with trimmed geometries.

Study on the bearing capacity of micropiles in plateau mountainous area: A case study of a power supply project in a traction station in Sichuan

As a new type of environmental protection foundation, micropile has the advantages of convenient construction, small floor area, and has a broad application prospect. This paper takes a power supply project of a traction station in Sichuan as an example, and uses ABAQUS numerical analysis software to simulate the micro-pile foundation of the project site, then the influence of pile length and pile diameter on the bearing capacity of micro piles is analyzed. Combined with the load-bearing requirements of the transmission line for the foundation, it is believed that the micro-pile foundation in the plateau mountain area is prone to damage due to failure to meet the pull-out requirements. The research results provide a reference for the design and application of the micro-pile project in the plateau mountain area in the future.

Creep-Effected Dynamic Response of a Concrete-Filled Steel Tubular Member in Axial Compression and Impact Load

The finite element model of a tubular member under the combined action of axial compression, creep, and axial impact was constructed with the numerical analysis software, to evaluate the core concrete creep effect on the dynamic responses of a steel tubular member in axial compression. In the model, the creep effect of core concrete of different age is equivalent to the change of its elastic modulus. Then, the dynamic responses of a tubular member in axial compression and impact were simulated considering the creep effect, time-history curves of impact load, contact time, axial deformation, stress and strain were plotted, and the effect of creep on them was discussed. The impact load peak decreases with the development of the core concrete creep, and the most is about 51%; the contact time and axial deformation increase; the concrete stress decreases, but the concrete strain increases greatly. The minimum and maximum principal concrete strains after 30 years exceeded those after 28 days by 6.35 and 8.6 times, respectively. The core concrete creep has a less effects on the stress and strain of the steel tube. The fruits provide a scientific help for the impact resistance design of a concrete-filled steel tubular member in axial compression.

Stability analysis of Cavern No. 5 with the largest span in Heidong large ancient underground quarry

The Heidong Cavern Group of China includes 21 large-scale caverns that have remained stable for 1400 years. Cavern No. 5 of the Heidong Cavern Group is characterized by an unsupported span of up to 92 m, which is considered to be the largest span in a single underground artificial rock cavern. Cavern No. 5 may have gone through a period during which it was the only cavern and a period during which it had adjacent caverns; recent investigations have proved that Cavern No. 5 is suffering from considerably serious partial damage. The factors affecting the stability of Cavern No. 5, including waste rock accumulations, rock mass structures, surrounding rock quality, and cavern structures, were analyzed to prevent further damage and analyze the influence of the existence of adjacent caverns on the stability of Cavern No. 5. The numerical analysis software MIDAS GTS (Geotechnical and tunnel analysis system) was used to simulate and compare the stability of Cavern No. 5 under the single-cavern and adjacent-cavern cases. Research proves that when this cavern is independently considered and the remaining caverns are excluded, the arched roof structure is considerably favorable to ensure the cavern’s stability and the horizontal compressive stress of the roof becomes approximately equivalent to the vertical tensile stress. The horizontal forces generated by the cavern’s inclined roof contribute to the cavern’s stability. The horizontal compressive stress area of the roof and the effect of the arched structure decrease when adjacent caverns are present, causing the roof to become prone to tensile failure. These results provide a reference for modern underground engineering construction and a theoretical basis for long-term protection of the large and ancient Heidong Caverns.

Mathematical methods to unloading creep constitutive model of rock mass under high stress and hydraulic pressure

The main purpose of this paper is to study the unloading mechanical characteristics of rock mass unloading under high stress and high water pressure. An unloading creep test of deep sandstone was conducted under different initial stresses and hydraulic pressures by using the TFD-2000 rock triaxial rheological test system. Based on the experimental results, we can explore unloading creep properties and time-dependent deformation characteristics of rock mass. Deformation characteristics of rock masses during the attenuation and stable creep stages under different stresses and hydraulic pressure conditions were analyzed, and the variation laws of creep parameters in different creep stages were studied and fitted by a mathematical model. The applicability of the fitting results was discussed. A nonlinear unloading creep constitutive model and mathematicalmethods of rock mass under high stress and high hydraulic pressure was proposed based on element model theory. Parameters of this nonlinear creep constitutive model were recognized. Results demonstrated that the nonlinear deformation characteristics run through the entire creep stage. During the attenuation and stable creep stages, elastic deformation parameters generally present exponential functional variations with the increase in time and hydraulic pressure. In the accelerating creep stage, viscous deformation parameters also present an exponential functional variation. The test curve fits with the model curve obtained by the optimal numerical analysis software 1stOpt, which verifies the accuracy and applicability of the model. This study can provide theoretical references for accurate prediction of time-dependent deformation of deep rocks under high stresses and high hydraulic pressures.

Numerical study on sealing performance of supercritical carbon dioxide compressor dry gas seal

Aiming at the serious problem of gap leakage between the stator and rotor of the supercritical carbon dioxide compressor, the dry gas seal scheme for centrifugal compressor of small S-CO2 power system is designed in this paper. The sealing characteristics of the single-stage spiral groove dry gas seal in the S-CO2 operating environment are studied by the large-scale commercial CFD numerical analysis software ANSYS CFX. The leakage characteristics of the S-CO2 dry gas seal at different film thicknesses are obtained. The results show that the S-CO2 dry gas seal leakage flow rate increases linearly with the increase of the film thickness. The dry gas seal leakage flow rate under different film thickness is 0.04%∼0.45% of the S-CO2 compressor flow rate, which can meet the leakage requirements of the centrifugal compressor shaft end seal in the small S-CO2 power system.

횡단면선 위치 변화에 따른 여객선박의 선형 설계에 관한 연구

The purpose of this study is to investigate the interrelationship of how the ship's wave resistance performance changes with the change of the longitudinal position of the section line in the ship's lines, and to find a way to use it in the hull-form design. To this end, we developed a hull-form automatic change algorithm that can maintain the proper hull-form while moving the section lines in the longitudinal direction, and the computer program for a numerical analysis was developed to apply the developed algorithm. By applying the developed hull-form automatic change algorithm and the wave resistance performance prediction program, the numerical analysis package was constructed. The numerical analysis was carried out for the passenger ship. Numerical analyzes were carried out by moving the section lines of the passenger ship in the longitudinal direction, and the results were compared with each other. Based on the numerical results, we attempted to investigate the correlation between the section line movement and the wave resistance performance.

Optimization Analysis of Over-Sized Section Open-Off Cut Failure and Support

The open-off cut section of 1105 working face in Zhaogu II mine is the largest in China, causing considerable difficulties to the support work. The failure process of surrounding rock deformation, stress field, and stress state under original support of open-off cut is analyzed using FLAC3D numerical simulation analysis software. Analysis results show the large displacement of the bottom heave and two sides of the roadway. Furthermore, the vertical stress of open-off cut is greater than the horizontal stress, whereas horizontal stress is larger in the upper roof part. The shearing failure range of the open-off cut surrounding rock is large, indicating that the original support scheme possesses weak restraint capability to the surrounding rock and fails to effectively control deformation. Based on analysis and research results, the technical scheme of coordinated support for super-long anchor rod and anchor cable of over-sized section open-off cut with high-stress broken surrounding rock is put forward. The field industrial test shows that the coordinated support scheme of super-long anchor rod and anchor cable is reasonable and safe under a 9.2 m open-off cut section. With improvement of the working face, the deep rock layer on the roof at the open-off cut position of goaf first occurs evidently, whereas the shallow rock layer is unremarkable, indicating the stable rock formation in the anchorage area of the shallow super-long anchor. The super-long anchor rod plays a satisfactory role in support, and the control effect of broken surrounding rock is similarly satisfactory. Such condition can achieve large deformation of broken surrounding rock with high stress and super large section.

A Novel Encoding Strategy of Enhanced Broadband and Absorption Conformable Metamaterial for MW Applications

Analog metamaterials (MMs) manipulate their effective medium parameters with difficulty, when their geometric architecture is composed of hybrid compositions. However, genetic algorithms, calculation-analog search algorithms that seek for optimal solutions, can be applied to artificial metamaterial-architecture construction. This paper proposes a novel encoding strategy for metamaterial architecture construction that utilizes multi-parameter extremum-seeking optimization. The binary encoding and decoding of the geometric-layer thickness enables the form's final dimension to be based on the objective fitness function. The genetic algorithm iteratively optimizes the initial geometrical dielectric-layer thicknesses. Then, combining the initial optimized parameter with the composite-metal multi-loops' spatial distribution, the final metamaterials were analyzed using numerical analysis software. Based on a co-simulation disposition, the proposed metamaterial exhibits 2.5-GHz broadband features with over 80% physical absorption of spatial waves. The proposed metamaterial simultaneously presents low radar cross-sections, wide polarization insensitivity, and dynamical flexibility. Moreover, the proposed metamaterial, when loaded onto a reference antenna, exhibited good real application capability in radar cross-section reduction for physical passive-equipment invisibility. The numerical-simulation and experimental results of the MM's absorption and flexibility properties showed good agreement, suggesting the advantage of genetic-algorithm optimization co-simulated with numerical-analysis software for metamaterial architecture construction. It shows good potential application for complicated spatial-geometry formations.

Effect of crack length on tip field of 304 stainless steel SCC

Stress corrosion cracking (SCC) is one of the key issues affecting the long-term safe operation of high temperature pressure vessels and pipeline. In this paper, the effect of crack length on the SCC crack tip field of austenitic 304 stainless steel is studied by using a compact tensile specimen. Firstly, the finite element model of SCC crack tip creep is established by using ABAQUS, and the crack tip creep and creep to crack tip mechanics are analyzed. The influence of different crack lengths on crack tip creep and creep rate was studied. It can be obtained by numerical simulation analysis software. The high creep variable area is mainly concentrated in the near crack tip region. The crack length has a great influence on the SCC crack tip creep field. With the continuous expansion of the austenitic 304 stainless steel crack, crack tip creep variables and creep rates are also increasing. It provides a theoretical reference for the safety evaluation and analysis of high temperature pressure vessels and pipelines.

Performance analysis of wireless communication networks with threshold activation process and interference signals

In order to reduce energy consumption in wireless communication networks, the sleep mode in the energy saving strategy and the threshold activation process of the base station are considered. Combining with practice, the existence of interference signals and possible errors in the transmission of data packets are considered. At the same time, considering that the wireless communication network system has two channels and one of them is incompletely reliable, a queuing model of repairable M/M/2 multiple working vacations with start-up period, negative customers, feedback and N-strategy is established. Using quasi birth-and-death process (QBD) and Gauss-Seidel iterative method, the expressions of the average delay of the data packet and other performance indicators are given. Then, using MATLAB software for numerical analysis, the influence of system parameters on the average delay and other performance indicators is analysed. Finally, the social optimal parameters are found by constructing benefit functions.

Performance analysis of wireless communication networks with threshold activation process and interference signals

In order to reduce energy consumption in wireless communication networks, the sleep mode in the energy saving strategy and the threshold activation process of the base station are considered. Combining with practice, the existence of interference signals and possible errors in the transmission of data packets are considered. At the same time, considering that the wireless communication network system has two channels and one of them is incompletely reliable, a queuing model of repairable M/M/2 multiple working vacations with start-up period, negative customers, feedback and N-strategy is established. Using quasi birth-and-death process (QBD) and Gauss-Seidel iterative method, the expressions of the average delay of the data packet and other performance indicators are given. Then, using MATLAB software for numerical analysis, the influence of system parameters on the average delay and other performance indicators is analysed. Finally, the social optimal parameters are found by constructing benefit functions.

Sensitivity Analysis Of Influencing Factors On Tunnel Stability In Bad Geological Slope Sections

Based on a tunnel through slope of Yongji highway project, relying on ABAQUS geotechnical numerical analysis software, using the appearance of plastic penetration area for instablilty criterion, choosing 11 typical influential factors as independent variables to tunnel stability, the orthogonal test array L50(511) is used to analyze sensitivity of influence factors under evaluating indexes of safety factor to the tunnel stability and the maximum principal tensile on the inner surface of surrounding rock. Research results show that: there are some certain differences between calculation results of safety factor and maximum principal tensile, but overall presentation represents favorable consistency, and the sensitivity of influence factors to the stability of tunnel through unfavorable geological slope can be preferably annlyzed by orthogonal test. The influence of the cohesion of rock c, the horizontal distance d between tunnel centerline and slope toe, the inclination angle of slope α are significant. Comprehensive consideration of safety factor and maximum principal tensile of tunnel circumference is more perfect than one-sided safety factor when performing the analysis of tunnel stability. The research results of this paper can provide reference to design, construction of similar tunnels.

Rapid Transfer Matrix-Based Calculation of Steady-State Temperature Rises in Cable Ducts Containing Groups of Three Phase Cable

This paper presents a heat transfer matrix and superposed thermal field-based method that can rapidly calculate steady state temperature rises in three-core cable groups laid in ducts. The temperature rise of any cable is a combination of self-reaction and interaction from other cables. A heat transfer matrix is formed by self-reaction coefficient and interaction transfer coefficient representing the thermal characteristics of the cable groups in ducts. The heat transfer matrix can be obtained by enough samples including temperature rise and cable losses based on numerical analysis, trial or commercial software. Rapid calculations can then be performed by simplify iteration of temperature-loss. Extraction of the transfer matrix using CYMCAP ampacity and temperature calculation software and application of the fast calculation method are illustrated and compared, confirming the feasibility and relative simplicity and accuracy of the fast calculation method.

Location Selection and Control Technology of New Driving Roadway in Upward Mining Roof

Based on the engineering background of the belt conveyance roadway in the north wing of Zhuxianzhuang Coal Mine, this paper puts forward and analyses the existing problems in the optimization of the roof roadway location in upstream mining, and studies the movement law of overlying strata under different mining heights by FLAC3D numerical analysis software. On this basis, the orthogonal test is used to analyze the optimization of different location of roadway in overlying strata, determine the weights of three factors affecting the selection of roadway location, and put forward a reasonable roadway location for belt conveyance roadway in the north wing of Zhuxianzhuang Mine. According to the occurrence and use of surrounding rock of belt conveyance roadway in North Wing of Zhuxianzhuang Mine, two schemes of zonal support are put forward. Industrial test shows that the support effect is greatly strengthened and the support condition is improved, which can be used as a reference for the location selection of coal mine roadway and surrounding rock control under similar geological conditions.

Effects of Nonuniform Fiber Geometries on the Microstructural Fracture Behavior of Ceramic Matrix Composites

Microstructural fracture behavior of a ceramic matrix composite (CMC) with nonuniformly distributed fibers is studied in the presentation. A comprehensive numerical analysis package to study the effect of nonuniform fiber dimensions and locations on the microstructural fracture behavior is developed. The package starts with an optimization algorithm for generating representative volume element (RVE) models that are statistically equivalent to experimental measurements. Experimentally measured statistical data are used as constraints while the optimization algorithm is running. Virtual springs are utilized between any adjacent fibers to nonuniformly distribute the coated fibers in the RVE model. The virtual spring with the optimization algorithm can efficiently generate multiple RVEs that are statistically identical to each other. Smeared crack approach (SCA) is implemented to consider the fracture behavior of the CMC material in a mesh-objective manner. The RVEs are subjected to tension as well as the shear loading conditions. SCA is capable of predicting different fracture patterns, uniquely defined by not only the fiber arrangement but also the specific loading type. In addition, global stress-strain curves show that the microstructural fracture behavior of the RVEs is highly dependent on the fiber distributions.

Development of car wishbone using sheet metal tearing process via the theory of inventive problem-solving (TRIZ) method

In the automotive industry, sheet metal forming process design is of great importance. The cold forming process in particular is the most widely preferred of these methods. In the production of car parts in complex forms, forming problems such as tearing, wrinkling, back spring and unwanted thinning can appear. Recently, numerical analysis technology and software tools have been widely used in process design and metal forming. Elimination of these problems without the use of analysis programs means the use of the trial and error method, which results in much wasted time and huge costs. In addition to the use of analysis programs, resolving problems without mold process and design knowledge is also problematic. In this study, the theory of inventive problem-solving (TRIZ) approach was utilized to reach an analytical solution. In this methodology, the improving and worsening features were determined and a TRIZ 39 × 39 contradiction matrix was created which led to the solutions. Virtual experiments were carried out on a wishbone mold model designed via the Siemens NX 12 CAD program using the Autoform R7 analysis program. Real environment experiments were then performed, and the problem of tearing during the forming process was eliminated. The measured thickness value of this area, which was formed without tearing, was measured as 2.7 mm in the virtual environment experiments and 2.9 mm in the real environment experiments. In addition, the wishbone was subjected to two-axis (x and z) dynamic testing, with acceptable values reached at 500,000 cycles.