Dimensional Analysis Method Research Articles

Application of nano-scratch technology to identify continental shale mineral composition and distribution length of bedding interfacial transition zone - A case study of Cretaceous Qingshankou formation in Gulong Depression, Songliao Basin, NE China

Bedding is the smallest macroscopic layer in a sedimentary sequence, usually containing different mineral compositions and ranging in thickness from a few tens of micrometers to a few millimeters. The microscale mineral composition and mechanical properties of the bedding interfacial transition zone (BITZ) have a significant influence on the crack propagation mode, which further leads to changes in hydraulic fracturing efficiency. At present, most of the identification of the shale mineral composition and the distribution length of the bedding interface transition zone relies on scanning electron microscope, but this method can only obtain the surface morphology and cannot further evaluate the mechanical properties. In this paper, the mechanical parameters such as friction coefficient and fracture toughness of shale samples from Songliao Basin were measured by nano-scratching technique. The damaged shapes and mineral composition in the scratched area were analyzed by scanning electron microscope. Indentation depth and fracture toughness data obtained from scratch tests were fitted with a Gaussian function to determine mineral composition. The slope of the d2-L curve is closely related to the mechanical behavior of minerals and is considered an effective parameter for identifying mineral composition. Based on the fluctuation characteristics of friction coefficient and fracture toughness curve, a quantitative method of shale BITZ distribution length based on linear regression is proposed, and the upgrade from single-parameter to multi-parameter combination is realized by using the method of dimensional analysis. The results of the study show that plastic minerals can effectively absorb energy and convert it into volume deformation and the rapid release of strain energy from brittle minerals results in the collapse of rock debris. The identification of mineral composition based on fracture toughness is a more accurate and effective method compared to the scratch depth and the slope of the d2-L curve. As the influence of mechanical performance was not considered, the length of BITZ distribution determined by SEM was significantly smaller than the analysis results of mechanical parameters. Compared with the friction coefficient method and the fracture toughness method, the dimensionless parameter method integrates several mechanical parameters and has high accuracy and applicability in identifying the distribution length of the interfacial transition zone of shale bedding. The results will help study the mechanical properties of different mineral interfaces of shale at the microscopic scale using the nano-scratch technique.

Empirijski model koji integriše dimenzionu analizu i Bok-Behnken dizajn za detekciju pukotina u lopaticama ventilatora rotora

Due to continuous operations and manufacturing errors, fatigue cracks can emerge after hours of service; this causes a fan blade failure and potentially ruins an entire engine, turbo machinery, or rotating machinery of a similar kind. This paper focuses on the condition monitoring of the fan blade for detecting cracks occurring in these blades by analyzing the vibration responses. The mathematical formulation is carried out using the matrix method of dimensional analysis, which is dependent on the fundamental quantities of force, Length, Time, and Temperature (FLTƟ) systems of units. Numerical analysis in ANSYS software is done to comprehend the blade harmonic response for the cracked blade condition. Experimentation is also carried out on Tiera fault simulation machinery equipment, where vibration responses are measured and analyzed for crack detection in the blades. The tests were performed for three different cracks of different lengths and analyzed by varying parameters such as load speed, for which experiments are planned using a Box-Behnken design method. The test results were confirmed with the model equations developed, and notable similarities were seen between the analytical, numerical, and experimental analyses. Thus, the proposed study will help detect the cracks in the blades, thus reducing the serious accidents or failure of the machinery.

Modeling of pressure losses in a cylindrical duct with rectangular ribs

AbstractIn order to improve the thermal performance of heat exchangers and air collectors, we insert various forms of artificial roughness, known as ribs, into the useful duct. These ribs promote the creation of turbulent flows and enhance heat transfer by conduction, convection and radiation.However, the introduction of these ribs leads to an increase in pressure drop, requiring higher mechanical power to pump the heat transfer fluid. This experimental study focuses on estimating, using empirical approaches, the pressure losses induced by rectangular ribs with an inclined top. The ribs are made from 0.4 mm galvanized sheet steel.An experimental set-up was designed to measure the head losses generated by the ribs, from the point of entry to the point of exit from the useful duct. Using the dimensional analysis method, correlations were established to evaluate head losses as a function of flow regime and rib geometry and configuration (including different geometries for rib arrangement over the configuration area).

КРИТЕРИАЛЬНОЕ УРАВНЕНИЕ ПРОЦЕССА СЕДИМЕНТАЦИИ В ПЕРЕХОДНОМ РЕЖИМЕ

Using the method of dimensional analysis, a general form of the criterion equation for the pro-cess of deposition of solid particles in a layer of liquid is obtained. The coefficients of the equa-tion for the process of sedimentation of sand particles in the transition regime were determined experimentally

Study on the effectiveness of impact factor in underwater explosion model test

The dimensionless quantity is the invariant under the unit conversion, and the only choice to characterize the laws of physics. Aiming at the similarity law of underwater explosion model test, the deficiency of traditional impact factor and the similarity condition of single value of model test are analyzed by using dimensional analysis method and combining with domestic and foreign research. In view of the shortcomings of traditional impact factors, a new impact factor is derived from the perspective of single-value similarity based on the impact dynamic response characteristics of underwater explosion structures. Taking the midship cabin structure of a certain frigate as the prototype, the scale model tests are designed based on the traditional and new impact factors respectively. The effectiveness of the impact factors is evaluated from the aspects of structural damage characteristics, dimensionless deformation deflection, dimensionless velocity and dimensionless acceleration at the center of the structure. To account for the impact of structural characteristics, scale ratio, and proportional distance on the impact factor's effectiveness, various grillage, cabin, and hull girder model tests are conducted using ships of different tonnages as prototypes. The results of the model test, guided by the new impact factor, align well with the prototype test data. In contrast to the traditional impact factor, the model test exhibits greater precision for predicting structural responses, with a broad spectrum of potential applications.

Experimental Study on Gas-Solid Two-Phase Flow Characteristics of a Vertical Cyclone Combustor System.

According to the design and operational parameters of the cyclone liquid slag-discharging boiler, an experimental platform for the cyclone burner was designed and constructed in a cold state based on the principle of similarity. The experimental study investigated the effects of parameters, such as swirl-vane angles, coal concentration, operating parameters, and particle size, on the flow distribution and vertical riser resistance characteristics of the vertical cyclone burner. The results showed that there were differences in flow distribution among the cyclone burners, and the most uniform flow distribution was achieved when the swirl-vane angle of the primary air was 30°. The concentration of pulverized coal significantly influenced the pressure drop in the vertical ascending section, which increased with higher concentrations of pulverized coal. When the concentration of pulverized coal remains constant, the pipeline pressure drop is minimized at a primary air velocity of 7.5 m/s. As the secondary wind speed increased, the pressure drop consistently rose; when the secondary wind speed is 22 m/s, the pressure drop of the pipeline is the maximum; however, excessively high secondary wind speeds were found to be detrimental to the formation of an optimal aerodynamic field in the burner. Furthermore, when the pulverized coal concentration was held constant, materials with larger particle sizes exhibited the highest pressure drop. When the particle size increases from 50 to 150 μm, the pressure drop of the vertical riser segment also increases. Finally, based on the Barth additional pressure drop theory, the pressure drop formula of the vertical riser is fitted by a dimensional analysis method, and the correlation formula of the pressure drop test of gas-solid two-phase flow in the vertical riser is obtained.

On the Similarity Relationship between the Structural-Steel Prototype and the 304-Stainless-Steel Dynamic Scale Model

Due to the size limitations of shaking tables, dynamic scale models of large-span space structures for engineering have small cross-sections and thin wall thicknesses. It is difficult to use the structural steels commonly used in prototypes to make dynamic scale models. In this paper, 304 stainless steel is proposed for making the scale model, and the similarity relationship between the structural-steel prototype and the 304-stainless-steel dynamic scale model was studied. Firstly, a uniaxial test was conducted to study the elastic modulus similarity and the yielding stress similarity. The test results demonstrated that the elastic modulus similarity ratio was 1:1, and the stress similarity ratios of the 304 stainless steel and the three typical structural steels were 1:1 (Q235 steel), 1:1.5 (Q355 steel) and 1:1.8 (Q420 steel). Then, the similarities of other variables were derived using the dimensional analysis method. In the end, a numerical analysis was conducted to verify the similarity relationship between the structural-steel prototype and the 304-stainless-steel dynamic scale model. In the numerical analysis, a single-layer spherical reticulated shell structure and a dynamic scale model with a length similarity ratio of 1:20 were established by using the ABAQUS 2021 software, and the node displacement, the element internal force and natural vibration characteristics were analyzed. The results show that standard deviations of the displacements, the internal forces and the natural vibration frequencies between the prototype and the scale model were within 5%. It turns out that the proposed similarity between the structural-steel prototype and the 304-stainless-steel dynamic scale model was applicable in the elastic stage. The findings provide a reference for designing a dynamic scale model of large-span space structures for engineering by using 304 stainless steel.

Uncertainty-oriented optimal impedance control for EPS-human system with reliability evaluation

This study proposes an interval optimal impedance control method for the electric power steering- human (EPS-H) system with reliability constraints. Considering the relationship between the lateral control using electric power steering of the vehicle and the human, a position-based impedance control model for the integrated EPS-H system is first developed. Polynomial chaos expansion in the surrogate model is employed to establish the interval state-space equation to obtain the bounded responses of the impedance control system using the interval dimensional analysis method. Moreover, the influence of uncertain parameters on the overall control system is obtained by deriving the interval optimal control law consisting of the interval linear quadratic tracking (LQT) inner loop and the interval impedance control outer loop through the interval uncertainty analysis. Furthermore, a non-probabilistic time-varying reliability method is proposed to evaluate the safety of the whole impedance system using the partial derivatives with respect to the uncertain parameters derived from the interval state-space equation. Regarding the nominal cost function and steady-state error of nominal responses as two optimization objectives, the multi-objective reliability-based design optimization is built and solved. Finally, a numerical example of the impedance control model for the EPS-H system is applied to verify the effectiveness of the proposed method.

A New Model for Cleaning Small Cuttings in Extended-Reach Drilling Based on Dimensional Analysis

A wellbore’s cleanliness affects drilling efficiency, economy and drilling safety directly in extended-reach drilling operations. Wellbore cleaning in extended-reach drilling has always been a tough problem. Field experience has shown that inefficient transport of small cuttings is a main factor for excessive drag and torque during extended-reach drilling. However, very little is known about the transport of small cuttings. In this paper, we use the data fitting method of dimensional analysis and regression analysis to establish a wellbore cleaning model for high-inclination sections, then use water and Polyanionic Cellulose (PAC) as a drilling fluid to analyze the settlement cleaning of small cuttings in the wellbore. The data from the example wells were used for field simulations to finally derive many factors like drilling fluid density, drilling fluid displacement, drill pipe rotation speed, diameter of cuttings and annulus hydraulic diameter, which affect the thickness of the dimensionless cutting bed. The results show that the dimensionless cutting thickness decreases with increasing drilling fluid density, drilling fluid displacement and drill pipe rotation speed; and increases with increasing cutting size and annular hydraulics diameter. Meanwhile, the effect of drilling fluid discharge, drill pipe rotation speed and cutting size on the thickness of the dimensionless cutting bed decreases as their values increase. This model can be utilized to design parameters in drilling and to predict the transport of cuttings in high-inclination sections. The successful establishment of the wellbore cleaning model for small cuttings in high-inclination sections of extended-reach drilling wells is highly innovative, which is a successful combination of theory and practice and has important guiding significance for promoting the development of wellbore cleaning technology.

Exploring consumer segments defined by affective responses to naturalness in logo design

PurposeFocusing on small- and medium-sized enterprises (SMEs), which are characterized by resource restrictions, this paper aims to explore consumer segment profiles by considering demographic, personality and creativity traits to determine whether consumers with different profiles exhibit distinct affective reactions to different logo design types (organic, cultural and abstract).Design/methodology/approachThis exploratory study incorporates recent methodological developments, such as the novel response style correction method, to account for response style effects in evaluations of affect toward logo design. In separate analyses, respondents are segmented according to response style–corrected logo affect and personality and creativity items. The segmentation analysis relies on reduced k-means, a joint dimension and cluster analysis method, which accounts for dependencies between items while maximizing between-cluster variability. A total of 866 respondents from the Iberian Peninsula (Portugal: n = 543; Spain: n = 323) participated.FindingsBased on a study using unknown logos (proxy for lower levels of budget communication, characteristics of SMEs), results reveal that there are three segments of consumers based on their affective response toward logo design: logo design insensitives, cultural logo dislikers and organic logo lovers. These segments are associated with different personality traits, creativity and biological sex (although biological sex is not a discriminant variable).Research limitations/implicationsThe decision not to control logos by color, to increase external validity, could limit the study’s internal validity if this aspect interacts with relevant study variables. Nevertheless, the empirical evidence can be used to further test associations between consumer profiles and responses to logo design.Practical implicationsFindings highlight the relevance of considering complex profile segments, combining demographics, psychographics and creativity to predict affective consumer responses to brand logo design. This research provides guidelines for SMEs when choosing or modifying their logo design to appeal to different consumer segments.Originality/valueThis study provides managers of SMEs (less present nowadays in empirical studies) with evidence suggesting that complex customer profiles help to understand differences in affective responses to natural logo designs. Furthermore, it relies on the use of a novel methodological development that improves the accuracy of the exploratory study developed.

Experimental and Numerical Study on the Low Velocity Impact Behavior of ABR Pipe

The low velocity impact load on pipes during transportation, construction and operation will cause pipeline damage and lay hidden dangers for the safety of pipeline engineering. To study the low velocity impact performance of pipes made of acrylate polymer blended with polyvinyl chloride resin for water supply (ABR), 20 sets of specimens with different heights and different masses of drop hammer were carried out to study the mechanical properties of ABR pipes. Based on the impact time curve, the energy dissipation capacity and impact peak value of ABR pipe specimens were analyzed, and the empirical calculation formula of impact force peak based on the test data is obtained by the dimensional analysis method, with a relative error ranging from −7.8% to 4.1%. Moreover, the finite element numerical simulation of ABR pipe specimens subjected to impact load is carried out, and the strain development law and failure mode of the pipe under low-speed impact load are analyzed. Therefore, the calculation formula of peak impact force and failure mode proposed in this paper can provide safety assessment methods for pipeline engineering designers and constructors.

A dimensional analysis based multi-scale thermal damage framework of brittle materials at elevated temperatures

Research on macro-scale damage prediction and micro-scale damage mechanisms of brittle materials at elevated temperatures is extremelyimportantto the design and application of practical engineering structures. In this study, a multi-scale thermal damage framework is proposed for both describing macro-scale damage evolution and collective micro-scale cracks behavior of brittle materials atelevatedtemperatures. In the framework, the evolution equation of ideal micro-crack system is deduced to establish the relationship between the macro-scale damage and the micro-scale crack nucleation and growth based on dimensional analysis method. To support the multi-scale thermal damage framework, the multi-scale damage of the benchmark fracture test of the Brazilian disk at elevated temperatures is predicted and compared with the experimental results. The results support the effectiveness and ability of the multi-scale thermal damage framework, which can achieve thermal damage prediction of brittle materials in macro-scale as well as physical mechanisms description in micro-scale.

The Blasting Vibration Characteristics of Layered Rock Mass under High-Pressure Gas Impact

Firstly, the experimental test of blasting vibration was carried out to study the propagation characteristics of the peak particle velocity (PPV) and dominant frequency (DF) of the blasting vibration of layered rock mass under high-pressure gas impact. The test results show that the PPV and DF of blasting vibration of layered rock mass decrease gradually with the increase in distance from the explosion source. The PPV and DF of layered rock mass under the same impact pressure of high-pressure gas are lower than those of single rock mass at the same measuring points. With the increase in hole spacing, the PPV and DF of blasting vibration become smaller, and the blasting effect first becomes better and then worse. Next, the relationship models between the PPV and DF and their influencing factors were deduced by the dimensional analysis method, which can be simplified as exponential forms that decay with the scaled distance. In addition, through a numerical simulation test, it was found that the optimal hole spacing recommended in an excavation example of an underground pipe gallery is 100 cm. Finally, the blasting vibration effects under the two excavation methods of high-pressure gas impact and explosive blasting were numerically simulated and compared. The results indicate that high-pressure gas impact can significantly reduce the blasting vibration effect of layered rock mass compared with explosive blasting. This study has important theoretical guiding significance and practical value for revealing the propagation law, forecasting and controlling the harm of blasting vibration effect of layered rock mass caused by high-pressure gas impact.

Analysis of the ammunition explosion seismic wave propagation law

The seismic wave generated in the ammunition explosion process is one of the important technical indicators to evaluate the ammunition damage power. It is of great significance to evaluate the ammunition damage power and study the targets damage characteristics. In this study, experimental studies were carried out with TNT explosive mass of 1.25 kg, 5.25 kg, 10.5 kg and 30.75 kg, and the ground vibration velocity time-history curves at different measuring points were obtained. The functional relationship between ground particle vibration acceleration and TNT explosive mass was established by dimensional analysis method, and the functional relationship calculation accuracy was verified by the measured test data. The results show that the particle vibration acceleration peak value is positively correlated with the TNT explosive mass, and negatively correlated with the measuring point distance; The particle vibration acceleration calculation function established by the dimensional analysis method has high fitting accuracy for the existing test data, and can be used to calculate the ammunition explosion ground vibration acceleration peak value. The research results provide a high-precision calculation method for the peak value of explosion seismic wave ground vibration acceleration.

Laboratory investigation of hydraulic jump in divergent-convergent conversions

Hydraulic jump is used as a significant energy-dissipater downstream of hydraulic structures, spillways, gates, and chutes. The novelty of this study is the simultaneous use of divergent-convergent basins to investigate the hydraulic jump characteristics. All experiments were conducted in a channel with a length of 11 m, a depth of 0.7 m and a width of 0.48 m. The results obtained from the divergent-convergent basin models have been compared with those of the sudden divergent basin, gradual divergent basin, classical basin and also with previous research. The results indicate that the ratios of depth (y2/y1) and jump length (Lj/y1) in the divergent-convergent basin have decreased by 48.6% and 122.9%, respectively, compared to the classic basin. These values are equal to 33.8% and 46.2% for the sudden divergent basin, respectively, and 31.7% and 69.9%, respectively, for the gradual divergent basin. In comparison with the classical basins, the energy dissipation in the divergent-convergent basin has increased by 26.8%. Finally, by using dimensional analysis and regression method, several equations were developed to predict the ratio of conjugate depths, length and energy dissipation for the divergent-convergent basins. According to this research, it can be concluded that the divergent-convergent basins with smaller dimensions and more energy dissipation have a much better performance than the standard ones.

Experimental study on equilibrium initiation and extension of multiple clusters of fractures based on true triaxial physical simulation

In the context of tight sandstone reservoirs in the Ordos Basin characterized by compact and heterogeneous rock formations, conventional fracturing techniques yield monolithic fracture shapes, rendering 3D reservoir reconstruction unattainable. This study investigates the principles governing balanced initiation and propagation of fractures in multi-cluster fracturing within unconventional fracturing technology. Employing a large-scale true triaxial simulation experiment system, we utilize the dimensional analysis method (π theorem) to design a physical simulation experiment similarity criterion. Through various experimental adjustments involving proportioning, curing, and mechanical testing, we generate an artificially cured rock mass with mechanical parameters akin to the target layer. The rock mass is maintained at a size of 30 cm × 30 cm × 30 cm. Systematic physical simulation experiments on unconventional volume fracturing are carried out using the 30 cm-sized dense sandstone outcrop rock mass. Taking the conventional fracturing technology as a reference and manipulating experimental conditions and design parameters, we simulate the non-equilibrium initiation and extension behaviors of fracturing fractures under five unconventional volume fracturing technologies, namely hydraulic pulse pretreatment, temporary plugging between clusters, flow-limiting method, cyclic loading and unloading, and pulse intermittent fracturing. Through this, we elucidate the non-equilibrium initiation and extension laws governing multi-cluster fractures. Comparative analysis with conventional fracturing, known for inducing stress interference on fractures and inhibiting their expansion, revels that the five unconventional volume fracturing techniques mitigate stress interference in multi-cluster fracturing. This promotes uniform fracture initiation and expansion, facilitating the creation of complex fractures and larger reconstructed volumes. Among these techniques, inter-cluster block fracturing stands out for its exceptional ability to generate complex fracture networks. The research culminates in the development and refinement of a balanced fracture and extension control technique tailored for multiple cluster fractures in bulk fracturing. This technique significantly contributes to enhancing the degree of 3D reconstruction achievable in unconventional tight oil and gas reservoirs.

Equivalent stiffness modeling of wedge-shaped cabin sections based on similarity theorem

The cabin section of an amphibious aircraft undergoes intense hydrodynamic and aerodynamic loads during water take-off and landing. These loads are crucial for its structural design and strength analysis. Therefore, a water impact test of the cabin section is essential for structural optimization. However, a full-scale model of the cabin section is costly and time-consuming due to its large size. This study proposes a design method that combines a partial similarity model and an equivalent similarity model based on the similarity theory. It constructs a half-scale model that has equivalent stiffness to the full-scale model. This reduces the test cost and improves the test efficiency. First, the cabin section is simplified as a wedge, and the components of the half-scale model are designed individually based on the dimensional analysis method of similarity theory. The equivalence is validated by finite element simulation and theoretical results. Then, the finite element simulation of the cabin section model is conducted, and the mechanical responses of the half-scale and full-scale models under static load are compared and contrasted. The results show that the half-scale model’s mechanical test can predict the full-scale model’s mechanical characteristics.

Organizational Analysis of UB (University at Buffalo)

In order to help our group better and more efficiently analyze the evaluation of specific company employees on their job roles, our group research selected the most familiar campus organization (the University at Buffalo – SUNY) as our subdivided target population. In this report, more than 30 UB professors’ privacy questionnaires were collected. We sorted out and tabulated 25 valid responses as data, and used the following four different dimensional analysis methods to sort out the surveyed data, analyzing the BIG 5 personality of the UB professors in the organization system, evaluating their job roles and characteristics through Motivating Potential Score (MPS), also reasonably scoring their average personal job satisfaction, and using Leader-member Exchange (LMX) theoretical data model analysis.

Limit load prediction analysis of X80 pipeline containing corrosion in mountainous landslide section

Currently in China X80 pipeline laying mostly concentrated in mountainous areas, oil and gas pipeline transmission distance, through the complex and diverse terrain, the pipeline by the buried environment will not only appear corrosion defects, but also by the impact of soil slippage to reduce the pressure-bearing capacity of the pipeline, resulting in pipeline perforation, broken, leading to oil and gas leakage accidents, further leading to fire, explosion and environmental pollution and other major safety accidents. In view of the important strategic position of oil and gas pipelines and the severity of accident hazards, it is important to study the ultimate bearing capacity of buried corroded pipelines. With this purpose, this paper analyzes the existing pipe-soil coupling theories based on the large-scale test in the field, optimizes the nonlinear contact model, and establishes a nonlinear corroded pipe-soil interaction model and verifies its accuracy. By using the existing soil load application function and coupling the actual soil slip data, the inhomogeneous movement of soil slip is realized. Based on the existing corrosion size characterization methods, the effect of corrosion size on the ultimate load carrying capacity of intact pipes was further verified by means of a combination of FEA and experiments. Specifically, the effects of soil slip under no load and internal pressure coupled conditions on the mechanical behavior of corroded pipelines are compared and analyzed; the necessity of considering soil slip is clarified; the influencing factors such as pipe corrosion size, operating internal pressure, and corrosion position are analyzed to reveal the failure mechanism of buried corroded pipelines in mountainous areas. By using the pipe displacement at the strain failure as the evaluation index, and using the dimensional analysis method to reveal the relationship between each influencing factor and the ultimate load, the ultimate load prediction formula for corroded pipelines under soil slip actions is derived. The research results can help evaluate the safety condition of existing operating pipelines, release early warning for the structure safety of pipelines, and provide guidance for the safety protection of pipelines in mountainous areas.

КРИТЕРИАЛЬНАЯ ЗАВИСИМОСТЬ ДЛЯ ОПРЕДЕЛЕНИЯ БРЫЗГОУНОСА В НАСАДОЧНОЙ КОЛОННЕ

A criterion equation is obtained for determining the spray entrainment in a packed mass transfer column by the method of dimensional analysis