Search

Shales with inclined beddings are frequently encountered in formation reservoirs as burial depth increases. However, limited research has focused on the influence of wellbore orientation and stress magnitudes when hydraulically fracturing inclined shale reservoirs. To close this research gap, a series of hydraulic fracturing experiments were conducted to investigate the effects of different wellbore orientation angles (α = 0–90°) and axial stress magnitudes (σv = 0–20 MPa) on hydraulic fracture initiation and propagation in inclined bedding shales. After fracturing, a 3D laser scanner is employed to characterize the fracture surface roughness, and three independent parameters (SD, θs, Rs) are used to quantitatively evaluate the roughness of the fracture surfaces. The results show that increasing the wellbore orientation angles (α) results in a first decreasing and then increasing trend of the fracture initiation pressure (Pi), breakdown pressure (Pb) and roughness of fracture surfaces. The wellbore orientation angle (α) of 45° is beneficial to reducing the Pi, Pb and roughness of the fracture surface. However, relatively low critical fluid pressures will facilitate the reduction of surface roughness under the impact of wellbore orientation. Increasing axial stress in inclined bedding shale reduces the fracture initiation pressure (Pi) and breakdown pressure (Pb) while enhancing the roughness of the fracture surfaces. In field fracturing, adjusting the wellbore inclined to the bedding (45° is preferred) and in the burial depth with a stress difference greater than 10 MPa benefit the improvement of hydraulic fracturing performance. These findings offer an essential reference for designing hydraulic fracturing in shale reservoirs. Highlights: Fluid pressurization rate is used to identify fracturing stage during fluid injection. Low pressures facilitate reducing surface roughness under the impact of wellbore orientation. Increasing axial stress facilitates fracture initiation and shale breakdown. High stresses facilitate complex fractures and rough fracture surface formation. [ABSTRACT FROM AUTHOR]

The estimation of mechanical and physical properties of coal reservoirs is important for the successful exploration and development of coalbed methane (CBM). Unlike conventional sandstone reservoirs, coal reservoirs exhibit greater sensitivity to stress, resulting in distinct mechanical and physical behaviors. In this study, uniaxial compression tests were performed on both low-rank and high-rank coal samples under different moisture conditions to reveal the mechanical and physical property changes with stress. The results indicate that during axial stress loading (up to 2.8 MPa), axial strain initially increases rapidly and subsequently at a slower rate, with an axial strain of 0.13–0.25% observed at the maximum axial stress. The instantaneous Young's modulus increases linearly before stabilizing, ranging from 618.01 to 4861.10 MPa, while the Poisson's ratio remains relatively constant or increases linearly, ranging from 0.002 to 0.165. This results in a negative exponential decrease in both porosity and permeability, with maximum reductions of 1.77–4.21% and 5.38–12.25%, respectively. The mechanical properties of coal are influenced by both the cementation effect of water at low water saturation and the softening effect at high water saturation, which results in axial strain decreases and then increases as the water saturation increases. Concurrently, the elastic modulus initially increases and then decreases, while the Poisson's ratio exhibits a less pronounced change or tends to increase. Consequently, there is a trend in which porosity and permeability first increase and then decrease. In addition, during stress unloading, the influence of water in coal induces a notable strain hysteresis phenomenon in water-containing coal samples, and this phenomenon is more obvious in the low-rank coals. [ABSTRACT FROM AUTHOR]

In the current study, the stress distribution in the pipe with viscoelastic behavior in presence of different loading conditions has been investigated. In order to connect the polyethylene (PE) gas pipes, the electrofusion sockets are used. Since joints are one of the most sensitive regions of a structure, it is very important to investigate the local stresses created at the joints of PE pipes. To study the stress changes in the buried pipelines and sockets, the numerical simulation of the problem has been carried out in ANSYS software. To validate the obtained numerical findings, the maximum values of the axial and von Mises stresses in the pipe and socket were compared with the values obtained from previous research, and an acceptable overlap was achieved. In this research, the stress distribution in the PE pipes buried in the soil with and without sockets in presence of thermo-mechanical load has been studied, comprehensively. In the finite element modelling, the pipe and socket are made of PE80 and PE100 materials, respectively. The research results showed that the electrofusion sockets are able to be employed to connect PE gas pipes in hot climate regions. Additionally, the outcomes obtained from viscoelastic socket and pipes compared with the isotropic pipe. The findings demonstrated that the maximum von Misses stress in viscoelastic pipe and socket reduces 21% in comparison with linear elastic state.Article Highlights: Induced stress components are created more in PE100 socket compared to PE80 pipe. The maximum von Mises stresses in the pipe and socket are in the safe zone for 50 years. A significant reduction in von Mises stress (about 21%) occurs in the viscoelastic state compared to the elastic case. [ABSTRACT FROM AUTHOR]

Gob is one of the most serious areas of coal spontaneous combustion. With the continuous increase of mining depth, the residual coal in gob bears increased axial stress, the rise of ground temperature, and the degree of fragmentation of mining coal and rock continues to increase, the external water in the mining process changes the water content of broken residual coal, under the influence of multiple factors, the prevention and control situation of coal spontaneous combustion in gob is becoming more serious. Based on the actual accumulation environment of residual coal in gob, this paper carried out the oxidation and temperature rise experiment of broken coal under the condition of water bearing and pressure. The variation laws of oxidation characteristic parameters such as outlet oxygen concentration, oxidation derived gas, oxygen consumption rate and heat release intensity were obtained. It is found that with the increase of water content of coal sample, the water content first promotes and then inhibits the oxidation process of coal. It is found that after water molecules form a relatively stable hydrogen bond with oxygen-containing functional groups, the total energy of the two-phase materials decreases, and the reason for the decrease of wetting heat release is analyzed. The influence mechanism of axial stress loading on coal spontaneous combustion oxidation process is studied. It is found that the increase of axial stress first promotes and then inhibits the process of coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Abstract In the current study, the stress distribution in the pipe with viscoelastic behavior in presence of different loading conditions has been investigated. In order to connect the polyethylene (PE) gas pipes, the electrofusion sockets are used. Since joints are one of the most sensitive regions of a structure, it is very important to investigate the local stresses created at the joints of PE pipes. To study the stress changes in the buried pipelines and sockets, the numerical simulation of the problem has been carried out in ANSYS software. To validate the obtained numerical findings, the maximum values of the axial and von Mises stresses in the pipe and socket were compared with the values obtained from previous research, and an acceptable overlap was achieved. In this research, the stress distribution in the PE pipes buried in the soil with and without sockets in presence of thermo-mechanical load has been studied, comprehensively. In the finite element modelling, the pipe and socket are made of PE80 and PE100 materials, respectively. The research results showed that the electrofusion sockets are able to be employed to connect PE gas pipes in hot climate regions. Additionally, the outcomes obtained from viscoelastic socket and pipes compared with the isotropic pipe. The findings demonstrated that the maximum von Misses stress in viscoelastic pipe and socket reduces 21% in comparison with linear elastic state.

Abstract The estimation of mechanical and physical properties of coal reservoirs is important for the successful exploration and development of coalbed methane (CBM). Unlike conventional sandstone reservoirs, coal reservoirs exhibit greater sensitivity to stress, resulting in distinct mechanical and physical behaviors. In this study, uniaxial compression tests were performed on both low-rank and high-rank coal samples under different moisture conditions to reveal the mechanical and physical property changes with stress. The results indicate that during axial stress loading (up to 2.8 MPa), axial strain initially increases rapidly and subsequently at a slower rate, with an axial strain of 0.13–0.25% observed at the maximum axial stress. The instantaneous Young’s modulus increases linearly before stabilizing, ranging from 618.01 to 4861.10 MPa, while the Poisson’s ratio remains relatively constant or increases linearly, ranging from 0.002 to 0.165. This results in a negative exponential decrease in both porosity and permeability, with maximum reductions of 1.77–4.21% and 5.38–12.25%, respectively. The mechanical properties of coal are influenced by both the cementation effect of water at low water saturation and the softening effect at high water saturation, which results in axial strain decreases and then increases as the water saturation increases. Concurrently, the elastic modulus initially increases and then decreases, while the Poisson’s ratio exhibits a less pronounced change or tends to increase. Consequently, there is a trend in which porosity and permeability first increase and then decrease. In addition, during stress unloading, the influence of water in coal induces a notable strain hysteresis phenomenon in water-containing coal samples, and this phenomenon is more obvious in the low-rank coals.

The axial compression performance of circular columns strengthened with carbon fiber-reinforced polymer (CFRP) was investigated using numerical simulation. The study's objective was to validate a finite element model to match results of experimental testing, to ensure consistent failure modes and load-displacement profiles. The investigation explored the impact of various parameters, including concrete strength, CFRP layer numbers, slenderness ratio, steel reinforcement ratio, and cross-sectional area, on CFRP column behavior. The analysis revealed valuable insights into stressstrain relationships and ultimate load-bearing capacity. This study provides vital information for structure engineering practices and design strategies in the industry, highlighting the significance to utilize CFRP technology to enhance structural performance, especially the consistent stress distribution on the concrete core. To understand the mechanical response of CFRP circular concrete columns, engineers can optimize design and construction techniques to create more efficient and durable structures elements, ultimately to improve public safety and to reduce maintenance processes. [ABSTRACT FROM AUTHOR]

The excavation and maintenance of buried natural gas pipelines can lead to deformation and stress redistribution of the pipelines and even cause secondary damage to the pipes with issues. To clarify the impact of excavation unloading on buried pipelines, this study established a finite element three-dimensional pipe-soil model, investigated the mechanical response of pipelines under layered excavation and evaluated various parameters impacting the response. The parameters analyzed include the diameter-thickness ratio of the pipe, excavation length and width, thickness of top covering soil, elastic modulus of soil, specific weight of soil and initial displacement of the pipeline. The study results showed that the pipeline bulges upwards during excavation unloading, the pipe top in the middle is under tension, and the bottom of the pipe is under compression. Therefore, the axial stress and vertical displacement both increase first and then decrease, and they are distributed symmetrically along the pipeline axis; excavating the initially compressed pipeline leads to high strain areas in the pipeline and even local buckling. The response to slope excavation is more pronounced than that to straight trench excavation; the additional response of the pipeline increases with the increase of diameter-thickness ratio, excavation width, thickness of pipe top covering soil and specific weight of soil, but it decreases with the increasing soil elastic modulus. The additional response is closely related to excavation length and the initial displacement. The results of this study can provide a reference for pipeline construction, maintenance, and safety assessment. [ABSTRACT FROM AUTHOR]

This article studies the distribution law of axial stress in mountain pipelines under the action of lateral landslides. Firstly, a mechanical model is established for analysis, taking into account the geometric nonlinearity of the pipeline and the physical nonlinearity of the longitudinal resistance of the soil outside the landslide. The theoretical calculation method for the axial stress of the pipeline under two conditions of tension or pressure is obtained, and the calculation formula for the axial stress of mountain pipelines under the action of lateral landslides is summarized. The finite element method was used to simulate and calculate buried pipelines affected by lateral landslides based on nonlinear contact problems. The single variable method was used to analyze the influence of soil parameters, landslide body parameters, mountain body parameters on both sides, and some other parameters on the axial stress of mountainous pipelines. The axial stress distribution of buried pipelines under different influencing factors was analyzed, and the axial stress distribution in four different directions of pipelines 0, 3, 6, and 9 was obtained, Analyze the variation pattern of axial stress in the pipeline at the location of stress concentration, and the results indicate that stress concentration occurs in the pipeline at the middle and edge positions of landslide displacement; According to the relationship between the axial stress of the pipeline and various influencing factors, the relationship between the maximum axial stress of the pipeline and a single factor is fitted, and the axial stress distribution law of the mountain pipeline under the lateral landslide effect is finally obtained. [ABSTRACT FROM AUTHOR]

In the present study, a functionally graded cantilever beam has been analyzed to observe its deformation behavior and stress variations. While the material properties (modulus of elasticity, modulus of rigidity, and density) have been varied along the height of the beam, Poisson's ratio has been considered a constant. The governing equations have been derived using Hamilton's Principle in the framework of higher-order beam theory. The derived equations are then simplified to a single equation, which is similar to that of isotropic beams. However, the work is extended to include a few higher-order terms and to study the effect of the incorporation of these terms on the resulting FG beam behavior. The development of a single governing equation for studying the statics and dynamics of an FG beam with the incorporation of higher-order terms is a unique part of the report. The solution of the governing equation is approached using approximate methods; in this work, the B-spline collocation technique is used to arrive at the results. A sixth-order B-spline basis function is used as an approximating polynomial, and the Greville abscissa has been used to generate collocation points. The obtained results have been verified against standard literature to find a satisfactory match. The results include comparative plots for normalized bending and transverse shear stresses, with and without the inclusion of higher-order terms. The results are then extended to study the effect of material index on the deformation and stress behavior of FG beams. The effect of aspect ratio on results is also studied for comparison of various beam theories. [ABSTRACT FROM AUTHOR]

This paper investigates the response of reinforced concrete shell elements subjected to all eight stress resultants (in-plane shear, two out-of-plane shears, torsion, two axial loads, and two moments). Twelve new experiments subjected to different combinations of in-plane and out-of-plane loads are presented. The experiments examine the influence of varying quantities of transverse shear reinforcement and concrete strengths. The paper also presents a new nonlinear, high-powered, macro finite element model called Shell II. The Shell II method is a three-layered model based on the equations of the Modified Compression Field Theory and is capable of predicting the full three-dimensional load-deformation response of shell elements subjected to combined loads. Shell II is also used to examine the experimental results in the context of in-plane versus out-of-plane shear-stress interaction diagrams. The results highlight the importance of considering combined loading in predicting the response of shells in three dimensions. [ABSTRACT FROM AUTHOR]

In response to the difficulty in effectively dealing with grouting defects in corrugated pipes within a suspension prestressed concrete arch bridge, a method for assessing the deterioration in the performance of prestressed concrete girders afflicted with grouting defects was established in the present study. Specifically, a time-varying model of steel strand corrosion within grouting defects was constructed by investigating the corrosion theory of steel strands. In addition, a full-scale numerical simulation model of the long-span prestressed concrete bridge was established based on a practical project. Through the described means, the long-term impact of steel strand corrosion at various locations, lengths, and quantities on the vertical displacement and axial stress of girders was elucidated. The results reveal that in the presence of corrosion affecting 16 steel strands located in the midspan bottom plate, a vertical displacement alteration of 17.55 mm was observed in the midpoint region of the girder over a 30-year period following the bridge's construction. Further, when considering the combined effects of concrete shrinkage, creep, and the corrosion of 16 steel strands in the midspan bottom plate, the axial compressive stress within the midpoint region of the girder decreased from an initial 6.30 MPa to 0.79 MPa over the same 30-year timeframe post-construction. It was observed that two indicators of vertical displacement and axial stress can be employed to evaluate the performance degradation of prestressed concrete bridge girders with grouting defects. The present findings may provide a reference for the operation and management of bridges with grouting defects. [ABSTRACT FROM AUTHOR]

A numerical simulation study was conducted to investigate the axial compression performance of circular columns strengthened with carbon fiber-reinforced polymer (CFRP). The study's primary objective was to validate a finite element program Abaqus model by matching results with previous experiments, ensuring consistent failure modes and load-displacement profiles. The investigation explored the impact of various parameters, including concrete strength, CFRP layer numbers, slenderness ratio, steel reinforcement ratio, and cross-sectional area, on CFRP column behavior. The analysis revealed valuable insights into stress-strain relationships and ultimate load-bearing capacity. This research provides vital information for structure engineering practices and design strategies in the industry, highlighting the significance of utilizing CFRP technology for enhanced structural performance, especially the consistent stress distribution on the concrete core. By understanding the mechanical response of CFRP circular columns, engineers can optimize design and construction techniques to create more efficient and durable structures, ultimately improving public safety and reducing maintenance processes.

Waste tyre rubber has become an environmental and health concern that needs to be sustainably managed to avoid fire hazards and save natural resources. This research work aims to study the structural behavior of glass fiber reinforced polymer (glass-FRP) reinforced rubberized concrete (GRC) compressive elements under monotonic axial compression loads. Nine GRC circular compressive elements with different axial and crosswise reinforcement ratios were fabricated. All the elements were 300 mm in diameter and 1200 mm in height. A 3D nonlinear finite element equation (FEM) was suggested for the GRC compressive elements using a commercial package ABAQUS. A parametric study has been done to examine the effect of various parameters of GRC elements. The test outcomes revealed that the ductility of GRC elements ameliorated with the lessening in the spaces of glass-FRP ties. The addition of rubberized concrete improved the ductility of GRC elements. The damage to GRC elements occurred due to the vertical cracking along the height of the elements. The estimates of FEM were in close agreement with the test outcomes. The suggested empirical equation depending on the 600 test elements, which considered the lateral confinement effect of FRP ties, presented higher accuracy than previous equations.

The test technology of fuselage panel subjected to combined load is an important technique for aircraft structure strength research. In order to discover the load characters of the fuselage panel subjected to combined internal pressure and shear load, “D” jig was utilized to simulate the boundary conditions of fuselage panel, the internal pressure load was applied by inflating, the shear load was applied by twisting the single box section, the internal pressure load test, shear load test and combined internal pressure and shear load test were completed. The measured stress is in good agreement with the theoretical result, the test shows that the stress level and stress distribution of the fuselage panel skin of the combined internal pressure and shear load test are the superposition of the stress level and stress distribution of the fuselage panel skin of the internal pressure load test and shear load test. Due to the superposition of the outer normal direction deformation of the fuselage panel under the internal pressure load and the normal direction deformation of the fuselage panel under the shear load, the error between the measured stress and the theoretical result in the combined internal pressure and shear load test is larger than that in the single load test, and the precision of the stress distribution becomes worse. [ABSTRACT FROM AUTHOR]

The excellent mechanical properties of grout sleeve is the key to ensure the integrity of the prefabricated structure. Combined with the bond-slip theory, the influence of the depth of the grout rib on the mechanical properties was studied in the new type grout sleeve by analyzing the parameters of the axial stress of the sleeve rib depth, the Mises stress of each rib, minor principal stress of the grout material and the ultimate stress of the sleeve. The results show that there is obvious correspondence between the depth of sleeve rib and its limit stress, the depth of sleeve rib increases, and the sleeve limit stress gradually increases. There is obvious correspondence between the sleeve convex rib depth and the displacement, the sleeve convex rib depth increases, the displacement change is slow, but the overall displacement difference is generally consistent. and there is obvious correspondence between the depth of the sleeve convex rib and minor principal stress of the grout material, the increase of the internal convex rib depth is beneficial to improve the overall mechanical properties of the grouting sleeve within a certain range of rib depth, however, when the depth of the convex ribs exceeds a certain range, the bearing capacity of the specimen decreases. [ABSTRACT FROM AUTHOR]

In high in-situ stress zones, cataclastic rocks have exerted a significant influence on the stability of engineering structures. However, the mechanical properties of cataclastic rocks can not be accurately studied due to difficulties in sampling and laboratory testing. In this paper, laterally confined compression tests for specimens that were obtained by the developed in-situ sampling devices were performed to investigate the stress states. A modified thick-walled cylinder model considering axial shear stress was introduced. The interaction mechanics model for a compressed sample and an equivalent single-layer cylinder was established. Based on the principle of elasticity, the laterally confined stress, the axial shear stress, and the axial stress of the sample were derived and obtained. Moreover, the effects of mechanical and geometric parameters of the equivalent cylinder on the force condition of the specimen were analyzed. The results show that the confined stress is positively correlated with the equivalent elastic modulus and the geometric factor. Therefore, the confined stress can be strengthened by increasing the elastic modulus, alternatively, increasing the outer diameter and decreasing the inner diameter. However, the axial stress is little affected by the equivalent elastic modulus and the geometric factor and is not affected by the equivalent Poisson's ratio. As the distance from the center height increases, the axial stress decreases linearly and the difference in axial stress becomes larger considering axial shear stress and ignoring axial shear stress. [ABSTRACT FROM AUTHOR]

Standard penetration test (SPT) has been widely used in offshore exploration because of its unique advantages. Unlike onshore exploration, offshore construction areas are characterized by high waves and water depths ranging from several meters to tens of meters. As a result, the reliability of offshore SPT is significantly reduced compared with onshore SPT. Currently, the probe rod length correction of SPT is not involved in geotechnical engineering investigation codes and related research, which greatly limits the application of this method in offshore exploration. Therefore, a series of SPTs were carried out in offshore environments with different water depths, with a maximum rod length of 65 m. The acceleration and axial stress at each test point of the rod were monitored by the dynamic signal data acquisition system, and the hammer impacting energy at each test point was obtained by Force–Velocity (F-V) method. The test results show that the correction of the rod length of the offshore SPT is different from that of the traditional SPT, and it needs to be further corrected for the water depth. In this paper, a modified method of rod length for offshore SPT is proposed, which can provide reference for the application of offshore SPT. [ABSTRACT FROM AUTHOR]

Current earth pressure calculation methods suffer from certain limitations because they do not consider the effect of retaining wall displacement. In this study, the soil behind the wall is assumed to be in a plane strain state, and drawing upon nonlinear elastic constitutive theory, an earth pressure calculation method is proposed, capable of considering both axial stress and wall displacement. To account for changes in soil modulus with confining pressure, the tangent modulus from the Duncan-Chang nonlinear model is introduced. Depending on the direction of the principal stress behind the retaining wall, the static earth pressure point, the major principal stress inflection point, and the minor principal stress second inflection point are determined. The conditions for the existence of the second inflection point are also given. These specific points, together with the limit earth pressure point, divide the earth pressures acting on the wall into six regions. The study provides earth pressure calculation formulas for T (translation) mode, RBT (rotation about a point below the base) mode, and RTT (rotation about a point above the top) mode based on the characteristics of wall displacement distribution in each mode. The proposed method exhibits good agreement with the test results, offering an effective approach for accurately calculating earth pressures related to displacement. [ABSTRACT FROM AUTHOR]

Background: Intervertebral disc degeneration (IVDD) is the initiating factor of adult degenerative scoliosis (ADS), and ADS further accelerates IVDD, creating a vicious cycle. Nevertheless, the role of the Wnt/β-Catenin pathway in ADS combined with IVDD (ADS-IVDD) remains a mystery. Accordingly, this study was proposed to investigate the effect of axial stress on the Wnt/β-Catenin pathway in nucleus pulposus cells (NPCs) isolated from DS-IVDD patients. Methods: Normal NPCs (N-NPC) were purchased and the NPCs of young (25–30 years; Y-NPC) and old (65–70 years; O-NPC) from ADS-IVDD patients were primary cultured. After treatment of NPC with overloaded axial pressure, CCK-8 and Annexin V-FITC kits were applied for detecting proliferation and apoptosis of N-NPC, Y-NPC and O-NPC, and western blotting was performed to assess the expression of Wnt 3a, β-Catenin, NPC markers and apoptosis markers (Bax, Bcl2 and Caspase 3). Results: N-NPC, Y-NPC and O-NPC were mainly oval, polygonal and spindle-shaped with pseudopods, and the cell morphology tended to be flattened with age. N-NPC, Y-NPC and O-NPC were capable of synthesizing proteoglycans and expressing the NPC markers (Collagen II and Aggrecan). Notably, the expression of Wnt 3a, β-Catenin, Collagen II and Aggrecan was reduced in N-NPC, Y-NPC and O-NPC in that order. After overload axial stress treatment, cell viability of N-NPC and Y-NPC was significantly reduced, and the percentage of apoptosis and expression of Wnt 3a and β-Catenin were significantly increased. Conclusions: Overloaded axial pressure activates the Wnt/β-Catenin pathway to suppress proliferation and facilitate apoptosis of NPC in ADS-IVDD patients. [ABSTRACT FROM AUTHOR]

Tunneling, especially in urban areas, affects many structures on the ground, which directly influences the usability and stability of the structures. The settlement of and axial stress on the pile foundation are important factors that determine the behavioral characteristics of the pile foundation. Therefore, this study uses numerical analysis and machine learning to derive a prediction model of pile axial stress due to tunnel excavation adjacent to the piled raft. Numerical analysis data were utilized for machine learning purposes, and the effects of the input data on the prediction model were scrutinized. The numerical analysis revealed that the change in the pile axial stress resulting from tunnel excavation differed depending on the pile's location, with the greatest axial stress reduction occurring in the center of the piled raft. Furthermore, the rate of reduction was higher in soils with lower relative densities. Several algorithms were employed to derive the prediction model, with tree-based algorithms displaying notable performance in predicting pile axial stress. Additionally, preprocessing the data with appropriate feature engineering techniques exhibited superior predictive power, and incorporating settlement data aided in enhancing the prediction model's performance. [ABSTRACT FROM AUTHOR]

To study the shear behaviors of jointed rocks reinforced by basalt fiber-reinforced polymer (BFRP) bars and steel–FRP composite bars (SFCBs), we conduct laboratory tests and numerical simulations to analyze the shear strength, shear stiffness, energy dissipation, and bolt failure modes. Our results show that the shear stiffness of the BFRP bolted specimen is lower than that of the specimens bolted by steel bars and SFCBs, but the residual shear strength is higher. SFCB-reinforced jointed rock has the highest peak shear strength, and its residual strength is similar to that of the steel bar bolted specimen. The total energy absorbed by the BFRP bolted specimen is comparable to that absorbed by the steel bolted specimen. When the bolt inclination angle is 60°, the shear strength of the BFRP bar bolted specimens is higher than that of the steel reinforced one. The failure characteristics of BFRP bar bolted rocks can be categorized as resin matrix fracture, resin matrix and fiber shear, and fracture of resin matrix and rocks. The failure modes of the SFCB divided into surface FRP failure and steel bending. Based on numerical results, BFRP bars have larger axial force than conventional bolts, but lower shear stress. The axial stress of the BFRP bar increases as the bolt inclination angle decreases. Moreover, the BFRP bar is more likely to cause shear cracks at the interface between the rock and the bolt. Highlights: Experimental and numerical tests were conducted on the jointed specimens reinforced by Basalt Fiber Reinforced Polymer bar and Steel-FRP composite bar. In terms of shear stiffness and residual shear strength, the jointed specimen reinforced by Basalt Fiber Reinforced Polymer bar and Steel-FRP composite bar differ significantly from steel. The specimens reinforced by Basalt Fiber Reinforced Polymer bar are sensitive to the effect of the bolt inclination angles and have higher shear strengths than conventional bolts at the bolt inclination angle is 60°. The axial force and shear force variation laws of different types of bolts were discovered. [ABSTRACT FROM AUTHOR]

Roof falls are currently one of the most dangerous threats associated with underground mining at great depth. Every occurrence of such an event poses a significant risk to the mining crew and disturbs the continuity of the mining process, which clearly affects the economy of the exploitation process. The development of a reliable monitoring system may significantly reduce the impact of eventual roof failure and will have a positive effect on the sustainability of the extraction process. Within this research study, a prototype of an instrumented rock bolt developed for continuous stress measurement is presented. The procedure of a 4-groove multilevel instrumented rock bolt is described and the calibration process is shown. Then, preliminary results of long-term in situ monitoring are presented. Based on the continuous monitoring of stress distribution within immediate roof strata, it was concluded that the developed instrumented rock bolt provides reliable results and is a very useful device, ensuring the possibility of early warning for miners about increasing roof fall risk. [ABSTRACT FROM AUTHOR]

Standard penetration test (SPT) has been widely used in offshore exploration because of its unique advantages. Unlike onshore exploration, offshore construction areas are characterized by high waves and water depths ranging from several meters to tens of meters. As a result, the reliability of offshore SPT is significantly reduced compared with onshore SPT. Currently, the probe rod length correction of SPT is not involved in geotechnical engineering investigation codes and related research, which greatly limits the application of this method in offshore exploration. Therefore, a series of SPTs were carried out in offshore environments with different water depths, with a maximum rod length of 65 m. The acceleration and axial stress at each test point of the rod were monitored by the dynamic signal data acquisition system, and the hammer impacting energy at each test point was obtained by Force–Velocity (F-V) method. The test results show that the correction of the rod length of the offshore SPT is different from that of the traditional SPT, and it needs to be further corrected for the water depth. In this paper, a modified method of rod length for offshore SPT is proposed, which can provide reference for the application of offshore SPT.

Current earth pressure calculation methods suffer from certain limitations because they do not consider the effect of retaining wall displacement. In this study, the soil behind the wall is assumed to be in a plane strain state, and drawing upon nonlinear elastic constitutive theory, an earth pressure calculation method is proposed, capable of considering both axial stress and wall displacement. To account for changes in soil modulus with confining pressure, the tangent modulus from the Duncan-Chang nonlinear model is introduced. Depending on the direction of the principal stress behind the retaining wall, the static earth pressure point, the major principal stress inflection point, and the minor principal stress second inflection point are determined. The conditions for the existence of the second inflection point are also given. These specific points, together with the limit earth pressure point, divide the earth pressures acting on the wall into six regions. The study provides earth pressure calculation formulas for T (translation) mode, RBT (rotation about a point below the base) mode, and RTT (rotation about a point above the top) mode based on the characteristics of wall displacement distribution in each mode. The proposed method exhibits good agreement with the test results, offering an effective approach for accurately calculating earth pressures related to displacement.

Piled raft foundation (PRF) is a cost effective and sustainable foundation option which can reduce the total and differential settlement, and improve the bearing capacity of the foundation in case of high-rise superstructures or marine structures. This study mainly focuses on a parametric analysis of PRF and also checks the impact of various design parameters on the structural and geotechnical aspects of PRF including the settlement of PRF and its components, raft-soil contact behaviour, bending moment, axial stress on pile, soil stress and settlement in different directions etc. To understand the contribution of piles in PRF, two factors such as relative improvement in the stiffness and settlement ratio are also evaluated. The results of the present study indicate that the differential and reference settlement can be controlled by the addition of piles under the raft, whereas the value of normalized differential settlement remains increasing with an increase in the pile spacing to diameter (s/d) ratio. In case of raft-soil contact behaviour, the contact pressure increases if the raft width is increased, but the rate of increment is prominent in case of a higher number of piles. The raft is showing both the sagging and hogging bending moment and as s/d ratio increases, bending moment also tends to increase. [ABSTRACT FROM AUTHOR]

As per most other earth science engineering problems, the underground coal geotechnical environment and the way in which roof and rib support interacts with the rock mass are complex issues. It is therefore generally recognised that without prudent simplification, the complexity of the problem will overwhelm all current geotechnical methods of modelling, not least for the reason that a rock mass can never be characterised to a level that allows a “non-simplified” analysis. The fact that numerical models, which are commonly purported to be a “simulation” tool and the so-called epitome of advanced geotechnical engineering, always need to be “calibrated” to a known reality is taken to be conclusive proof of this statement. While the problem should not be oversimplified (i.e. the dominant failure mechanisms or critical data input parameters should not be ignored), without question judicious simplification is at the heart of all engineering design, to the point that it has a well-established name – “reductionism”. The hypothesis addressed in this paper, is that horizontal and vertical stress-driven slender beam and column behaviour (which includes unstable Euler Buckling) are respectively the dominant (but not only) roadway roof and ribline behavioural mechanism that (if not controlled) can lead to excessive deformation, failure and eventual collapse. As a part of the Scientific Method, a hypothesis can only be tested via real-world observations, measurements and analyses in establishing it is a credible Theory. Utilising the Scientific Method, this paper demonstrates that slender beam/column behaviour is the dominant instability mechanism within a coal mine roof/rib subject to elevated horizontal/vertical stress conditions and therefore, must be representatively accounted for in any credible empirical, analytical, or numerical approach to coal mine roof/rib stability assessment and associated ground support design.

Tunneling, especially in urban areas, affects many structures on the ground, which directly influences the usability and stability of the structures. The settlement of and axial stress on the pile foundation are important factors that determine the behavioral characteristics of the pile foundation. Therefore, this study uses numerical analysis and machine learning to derive a prediction model of pile axial stress due to tunnel excavation adjacent to the piled raft. Numerical analysis data were utilized for machine learning purposes, and the effects of the input data on the prediction model were scrutinized. The numerical analysis revealed that the change in the pile axial stress resulting from tunnel excavation differed depending on the pile’s location, with the greatest axial stress reduction occurring in the center of the piled raft. Furthermore, the rate of reduction was higher in soils with lower relative densities. Several algorithms were employed to derive the prediction model, with tree-based algorithms displaying notable performance in predicting pile axial stress. Additionally, preprocessing the data with appropriate feature engineering techniques exhibited superior predictive power, and incorporating settlement data aided in enhancing the prediction model’s performance.

Highly complex engineering structures such as the body-in-white of a car consist of hundreds of different parts that are assembled using various types of joints such as welded and adhesive joints. The finite element method has been used extensively in various engineering fields to predict and analyze the dynamic behavior of assembled structures. However, despite the use of well-characterized individual subcomponent models, the predicted results frequently differ from measured results. This is believed to be because of the invalid assumptions of the joint model such as the material properties and other uncertainties associated with the assembly. This study investigated the use of a model updating method (MSC Nastran SOL 200) to identify the invalid assumptions and uncertainties in adhesive jointed composite structures and to minimize the difference between predicted and measured results. Results revealed that the stresses built-up in a structure during the assembly process are permanently retained in the structure after the adhesive is completely cured and that they cause a local stress stiffening effect, which is believed to affect the resonance frequencies of the structure. Introducing the effect of the stresses as an updating parameter in the model updating process increases the prediction accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Ingeniería (0121-750X) is the property of Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Bolts are important fasteners indispensable in the manufacturing field for their advantages, which include convenient assembly and disassembly, easy maintenance, refastenability to prevent looseness, and the avoidance of a phase change in the connected material composition. The precise control of the tightening force in bolts is closely related to the safety and reliability of the connected equipment or structure. Although there are many methods for estimating the tightening force applied to a bolt during assembly, poor accuracy in controlling the preload during the tightening process and a lack of monitoring to determine the residual axial force in service remain issues in evaluating the safety of bolted assemblies. As a nondestructive testing technology, ultrasonic measurement can be applied to successfully address these issues. In order to help researchers understand the theoretical basis and technological development in this field and to equip them to conduct further in-depth research, in this review, the basic knowledge describing the state of stress and deformation of bolts, as well as conventional testing methods are summarized and analyzed. Then, through a review of recent research of the ultrasonic measurement of the axial stress in bolts, the influence of the effective stressed length and temperature are analyzed and proposed methods of calibration and compensation are reviewed. In order to avoid coupling errors caused by traditional piezoelectric transducers, two newly proposed ultrasonic coupling technologies, the electromagnetic acoustic transducer (EMAT) and the permanent mounted transducer system (PMTS), are reviewed. Finally, the new direction of research of the detection of residual axial stress in in-service bolts that have been assembled to yield is discussed.

The pull rod under eccentric loading exists extensively in engineering project,the computations of its stress and strength directly affect its reliability,especially its dynamic stress computations. The elastic dynamic mechanics were used here to study the computations of the bending stress and axial stress of the eccentric loaded rod under steady force,and the analytic expressions were given,numerical example was provided to show the variations of the amplitude of the bending stress and axial stress with the disturbance frequency,the theoretical analyses and the computation results of given example show that the amplitude of the bending stress and axial stress obviously depend on the disturbance frequency,which is different from that of corresponding static problems. The analyses and conclusions given here have some references to the dynamic reliability design.

Under the special geological environment of the buried pipe, the ground is lost at the bottom of the pipe, which is created by various kinds of external factors. The pipe in the suspended state would be greatly deformed due to its own weight, internal pressure, and other factors, resulting in the failure of the pipeline. When a variable wall thickness weld occurs in the suspended section of the pipeline, the change of the pipeline stress will be more complicated and changeable. In this study, ABAQUS software is used to establish a pipe–soil model of variable wall thickness butt welds of suspended pipelines. The axial stress distribution with different affected factors in the pipe, the change of curvature, and Mises stress change of the entire pipe along the axial direction are obtained by analyzing the internal pressure, wall thickness ratio, suspended length, weld position, and cone length. The results show that the stress at the root of the weld changes significantly; therefore, the weld has a greater impact on the stress of the entire pipeline. The change of internal pressure has little effect on the stress at the pipe weld. As the suspended length increases, the change in stress at the weld is more obvious. When the weld seam is close to the soil, the support of the soil will gradually shift the maximum stress position of the pipe from the top of the pipe to the bottom of the pipe. With the increase in cone length, it will reduce the sudden change of pipe section and the change in stress effectively. The places where the curvature greatly changes along the axial direction are at the pipe–soil separation and the middle of the pipeline, while the stress reaches the maximum at the pipe–soil separation, and the place with the largest stress change is the weld in the middle of the pipeline.

Electrostatically actuated, bistable, curved micromechanical beams can exhibit latching, wherein the beams remain in two distinct stable states without an applied voltage. These structures could serve as building blocks in a variety of applications such as micromechanical logic elements, switches, non-volatile memories, and low power consumption sensors. However, the design of such devices is challenging since such structures are prone to symmetry breaking, which consequently inhibits latching. Generally, asymmetric responses may be circumvented by introducing a tailored axial compressive prestress. In this work we explore, both theoretically and experimentally, the influence of prestress on the single electrode, bidirectional dynamic switching of curved, latchable, single crystal Si $\approx 1000 \;\mu \text{m}$ long and $\approx 3.5\;\mu \text{m}$ wide beams. We use Joule heating to apply the necessary prestress required to eliminate symmetry breaking and ensure latching. In accordance with reduced-order model predictions, our experimental findings show that prestress plays a key role in the dynamic response of the beam. Our results demonstrate bidirectional operation using a single electrode, fostering a compact footprint device for tailoring the axial stress and dynamic conditions. [ABSTRACT FROM AUTHOR]

The deformation of a deep foundation pit in Ulanqab city was analyzed by in situ monitoring and numerical simulation data. First, a limit equilibrium method was used to evaluate the stability of foundation pit under non-supporting and ribbed plate anchored retaining wall support. The results show that the ribbed plate anchored retaining wall support could control the soil deformation effectively in deep foundation pit. Additionally, a three-dimensional finite difference model of excavation zone and reinforcement structure was established using FLAC3D software to simulate the excavation of deep foundation pit. The simulation results were verified by monitoring field data. The simulation results show that all the bolts are in the tension state, and the maximum axial force is located at the end of the bolt, with a value of 46.4 kN. Foundation pit excavation is a continuous stress release process, making the rock and soil of side wall of foundation pit slide towards the free surface. The largest deformation is 4.0 mm, near the side wall of foundation pit, consistent with the deformation monitoring results. [ABSTRACT FROM AUTHOR]

Water content, dry density, void ratio, depth of soil layer, and seismic loading may all exert influence on the seismic subsidence of loess. Many scholars have carried out seismic subsidence tests of loess to simulate the stress on soil using unidirectional (axial) vibration instead of bidirectional vibration. We conduct seismic subsidence tests of loess using two different dynamic stress loading methods, unidirectional and bidirectional dynamic stress. In addition, the effects of different dynamic stress loading modes on the development of seismic subsidence of loess are compared for a case-study in northwestern China. The results show that (1) the increasing ratio of radial stress to axial stress has exerted significant influence on the seismic subsidence coefficient of loess under the loading mode of bidirectional dynamic stress (2) there is a critical ratio of radial stress to axial stress for seismic subsidence of loess, ranging from 0.6 to 0.8; when the ratio of radial load to axial load is greater than the critical value, the effect of bidirectional load on the development of seismic subsidence is more remarkable (3) when the ratio of radial load to axial load is smaller, the seismic subsidence of loess calculated by the existing unidirectional stress loading method is safe for engineering projects. However, if the value exceeds the safety ratio range it is dangerous to conduct safety evaluations using the seismic loess subsidence. The prediction value of seismic subsidence at engineering sites directly affects the later foundation treatment and the safety of the overlying structures. The seismic subsidence calculation and evaluation method in this study may provide a scientific basis for safety evaluations of loess sites in northwestern China.

Roof falls are currently one of the most dangerous threats associated with underground mining at great depth. Every occurrence of such an event poses a significant risk to the mining crew and disturbs the continuity of the mining process, which clearly affects the economy of the exploitation process. The development of a reliable monitoring system may significantly reduce the impact of eventual roof failure and will have a positive effect on the sustainability of the extraction process. Within this research study, a prototype of an instrumented rock bolt developed for continuous stress measurement is presented. The procedure of a 4-groove multilevel instrumented rock bolt is described and the calibration process is shown. Then, preliminary results of long-term in situ monitoring are presented. Based on the continuous monitoring of stress distribution within immediate roof strata, it was concluded that the developed instrumented rock bolt provides reliable results and is a very useful device, ensuring the possibility of early warning for miners about increasing roof fall risk.

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Strain-softening analyses were performed around a circular bore in a Mohr–Coulomb rock mass subjected to a hydrostatic stress field in cross section and out-of-plane stress along the axis of the bore. Numerical procedures that simplify the strain-softening process in a step manner were employed, and on the basis of the theoretical solutions of the elastic–brittle–plastic (EBP) medium, the strain-softening results of the displacements, stresses and the plastic zones around the circular bore were obtained. The numerical solution was validated based on the fact that the strain-softening process became EBP when the softening slope was very steep and elastic-perfectly plastic (EP) when the softening slope was near zero. The results illustrated that the stresses and displacements in the rock mass surrounding the bore were affected by axial stress and that a proper consideration of out-of-plane stress was necessary. Moreover, the presented results can be used for the verification of numerical codes. [ABSTRACT FROM AUTHOR]

Coal particles are broken to varying degrees under the axial stress, thereby affecting the particle size distribution, which has an essential impact on coal spontaneous combustion (CSC). This work investigated the evolution behavior of the characteristic parameters and limit parameters of the coal oxidation process under different breakage degrees. Results showed that as the axial stress increased, the breakage degrees of coal gradually increased, while the permeability gradually declined. The increase in the breakage degree of particle induced by axial stress would promote the CSC process and increase the risk of CSC. The promotion effect reached the most prominent at 12 MPa and began to decrease at 15 MPa. Particle breakage and increasing specific surface area caused by stress were responsible for the change in CSC characteristic parameters. The reduction in permeability caused by stress dominated the changes in CSC limit parameters. [Display omitted] • Studied the breakage and permeability evolution during coal low-temperature oxidation process. • Increasing breakage degree accelerated the process and risk of CSC. • Axial stress of 12 MPa significantly impacted the CSC process. • Breakage degree and permeability affected the characteristics parameters and limit parameters. [ABSTRACT FROM AUTHOR]

Stiffeners support lateral pressure and axial load and are one of the essential members of a ship structure composed of stiffened panels. Their scantling formulae are important to ensure adequate strength against lateral pressure and for the rapid and proper initial design of hull structures. However, the current rule scantling formulae are based on the elastic beam formulation, and the effect of the simultaneous axial stress is considered differently by the rule as a coefficient for reducing the allowable stress. In this study, based on the fully plastic moment under the action of axial stress, the stiffener bending strength corresponding to the plastic hinge formation criteria (initial hinge and plastic collapse) was determined using simple theoretical formulae considering the additional lateral force induced by the axial stress on the deflected stiffener. Subsequently, the structural behaviors were investigated comprehensively by theoretical parametric studies based on various stiffener scantlings and loading combinations, which were further compared with the results of finite element analysis (FEA) based on the residual deflection criterion, thereby verifying the validity of the theoretical proposals. Consequently, by combining the findings from the theoretical and numerical investigations, the effect of the axial stress on the stiffener bending strength was expressed as closed-form coefficients. These proposed axial stress coefficients were verified to govern the actual structural behaviors well and are expected to provide a rational basis and contribute to improving rule-scantling formulae. • Deriving a theoretical method to evaluate the stiffener bending strength under the axial load. • Considering fully plastic moment and additional lateral force affected by the axial load. • Comprehensive finite element analysis employing residual deflection criteria corresponding to the initial hinge formation. • Closed-from axial stress coefficient proposed based on the comprehensive theoretical and numerical results. [ABSTRACT FROM AUTHOR]

According to the industry standard, low permeability and tight reservoir are highly stress-sensitive in laboratory tests. However, this phenomenon has not been effectively confirmed in the field production test. For this reason, a method to measure stress sensitivity by axial loading is proposed. By loading fixed axial stress, the measurement method achieves the effect of equivalent preloading fluid pressure. Meanwhile, the equivalent theoretical curve can be obtained by translating the curve. Through this method, the stress sensitivity of the core with microfracture is studied. According to the results, the stress sensitivity of the cores can be divided into two stages: the first stage is the non-opening stage of microfractures, in which the stress sensitivity is weak; the second stage is the opening stage of microfractures, in which the stress sensitivity increases sharply. When the permeability changes significantly, the corresponding pressure is the microfracture's opening pressure. In addition, if the abscissa of the experimental results corresponds to the field production data, the field stress sensitivity curve of the field reservoir can be obtained. Conventional stress sensitivity test shows that the four cores in the study block exhibit medium to strong stress sensitivity. According to the stress sensitivity curve analysis after curve translation, the stress sensitivity of the reservoir is about 25% in the elastic production stage, which is classified as weak stress sensitivity. This conclusion can effectively support the phenomenon of the unobvious stress sensitivity in the field production of low permeability and tight reservoirs. [ABSTRACT FROM AUTHOR]

Temperature and stretching are important factors in the high-temperature treatment of carbon fiber. The axial stress during carbon-fiber high-temperature treatment affects its ability to stretch. The high-temperature axial stress evolution mechanism of polyacrylonitrile-based carbon fiber was studied through in situ tension tests, Raman spectroscopy, X-ray diffractometry, elemental analysis, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, thermal expansion coefficient tests, and density methods. The high-temperature axial stress evolution of polyacrylonitrile-based carbon fiber involved three stages: rapid increase, rapid decrease, and relaxation. The highest stress and relaxation temperatures of the polyacrylonitrile-based carbon fiber were 1600°C and 1950°C, respectively. The main factors that affected the fiber axial stress included carbon-structure rearrangement and the effect of thermal expansion and cold shrinkage on fiber length. During the first stage (T < 1600°C), carbon-structure rearrangement after nitrogen atom removal increased the fiber axial stress. In the second stage (1600 ⩽ T ⩽ 1950°C), the difference in the thermal expansion of fibers that entered the graphite furnace and the cold shrinkage of fibers that exited the graphite furnace increased gradually, which resulted in a decrease in fiber axial stress by up to 1950°C, where the fiber relaxed and the third stage (T > 1950°C) began. The difference between expansion and shrinkage increased significantly, which increased fiber relaxation. Carbon fibers with fewer nitrogen atoms and more regular structures had a lower axial stress during high-temperature treatment, but the trend and characteristic temperature remained unchanged. The corresponding fiber high-temperature maximum stretching ratio and axial stress showed opposite trends below 1950°C. The ability to stretch the carbon fiber increased above 1950°C, which differed from the axial stress relaxation. [ABSTRACT FROM AUTHOR]

In the extrusion of clad composite materials with different flow stresses are usually used. This causes an inhomogeneous material flow which can induce sleeve or core fracture. In the present study, the material flow during indirect extrusion of copper-clad aluminum (CCA) rods was analyzed by means of experimental and numerical investigations throughout the process. In order to provide material models for the numerical analysis hot compression tests of the aluminum alloy EN AW-1080A and the copper alloy CW004A were carried out. The indirect extrusion was performed using a conical die with a semi die angle of 45° and an extrusion ratio of 14.8:1. The container was heated to 330°C, while billet, die, and ram were kept at room temperature. The extrusion trial was then modeled with the FEM based software DEFORM 2D. Cross sections were taken from the extruded rod and compared to the corresponding sections of the simulation with regard to the development of the equivalent copper cross section. As a result, the development of extrusion force and equivalent copper cross section could be clarified. The numerical investigations indicated a higher flow velocity for the aluminum core than for the copper sleeve at the bearing channel. Therefore, high tensile stresses and fractures of the copper sleeve were induced. Additionally, the validated numerical analysis made possible to determine the conditions for a successful co-extrusion of the analyzed CCA rod.

Internal pressure is a severe cyclic load for fuselage structure, and it is important to investigate the fatigue and damage tolerance characters of fuselage panel under internal pressure. Boundary condition simulation of fuselage panel subjected to internal pressure load is challenging, and the quality of the simulation influences the range of transition area and even the stress distribution size in examining area. To investigate the stress distribution of fuselage panel subjected to internal pressure, a new test method is proposed. “D” jig is utilized to simulate the longitudinal boundary conditions of fuselage panel, and “Arch” connectors are utilized to simulate the circumferential boundary conditions. Airtight end-plate is utilized to simulate the end of the fuselage barrel. Test fixture and fuselage panel specimen are designed and manufactured according to the boundary simulation requirements. Tests are conducted based on the proposed method. The test results show that hoop stress and axial stress in transition area are much more lower than in the test area. Hoop stress, axial stress and normal displacement in the test area are consistent with theoretic results. The proposed test method settle for engineering precision requirements and provides reference for configuration-selection tests of fuselage panel subjected to internal pressure load.