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Proposal for describing the uniaxial compression behaviour in the model of internal structure A working group of the German Association for Water, Wastewater and Waste (DWA) is elaborating new recommendations for highly deformable cut‐off walls. An important goal is the utilization of the plastic material behaviour of highly deformable cut‐off walls. The article presents a new model to characterize the distinct nonlinear‐plastic mechanical behaviour of such materials, especially in the context of uniaxial compression. The "model of the internal structure" in this form takes up basic descriptions from models developed especially in Japan in the 1960s and 70s for directional load transfer based on contact orientation in dry granular aggregates and extends them by an approach to take cohesive material properties into account. [ABSTRACT FROM AUTHOR]

Stress–strain curves are generally a very important material characteristic. For example, in numerical simulations, especially in sheet metal forming, stress–strain curves represent one of the most important data inputs. However, there is quite a wide range of parameters that influence their outline under the chosen technological conditions and, therefore, must always be taken into account. Among them, the influence of stress state and loading history is also relevant. In addition to that, to properly define the advanced yield conditions used in numerical simulations, it is also necessary to perform material tests under multi-axial stress states. For the above reasons, the present paper deals with the influence of the loading mode on the resulting outline of stress–strain curves under the equi-biaxial stress state at hydraulic bulge test (HBT). In light of the different loading modes, the classical continuous increase in pressure in accordance with ISO 16808 was compared with the so-called ramp test, where holding times for a duration of 90 s were applied. Two materials were selected for experiments, namely, a dual-phase steel (DP steel) with UTS of 500 MPa and an interstitial-free steel (IF steel) with a yield strength of 150 MPa. The results revealed totally different deformation behaviour of the tested materials depending on the used loading mode. Moreover, an evaluation of the microstructure was performed as well to clarify the measured results. The contactless optical system GOM Correlate Pro was used to evaluate the results of the HBT. [ABSTRACT FROM AUTHOR]

Highlights: What are the main findings? Proposes the method for deriving the state variables from the tested strain and deformation data; Proposes the method for expressing the state of stress of the asphalt airport pavement using state variables; What is the implication of the main finding? Proposes the method for expressing the state of stress of the asphalt airport pavement using state variables; What is the implication of the main finding? The National Airport Pavement Test Facility (NAPTF) in USA obtained the strain and deformation data of the asphalt airport pavement numbered as Track 3 under the wheel load traveling in the north area of Construction Cycle 7 (CC7). But, the classic theories and methods still could not find out the definite and essential working characteristics, such as the starting point of the asphalt pavement's failure process and the ending point of the normal working process. This study reveals the essential working characteristics of the asphalt airport pavement by modeling the tested strain and deformation data based on structural state-of-stress theory. Firstly, the tested data are modeled as state variables to build the state-of-stress mode and the parameter characterizing the mode. Then, the slope increment criterion detects the mutation points in the evolution curve of the characteristic parameter with a wheel load traveling number increase. Correspondingly, the mutation features are verified by investigating the evolution curves of the state-of-stress modes. The mutation points define the failure starting point and the elastoplastic branch (EPB) point in the working process of the asphalt airport pavements. The strain state-of-stress mode (Δεt) and characteristic parameters ( E j and Φ j ) presented an obvious mutation feature around the EPB point; in addition, the deformation state-of-stress mode (ΔDt) showed that the total deformation of the pavement changed evidently before and after the failure starting point, and the characteristic parameters ( E j and Φ j ) also presented an obvious mutation feature around the failure starting point, so both characteristic points could address the classic issues in the load-bearing capacity of asphalt airport pavements. Furthermore, the EPB point could be directly taken as the design point, and the failure starting point could be taken as the limit-bearing traffic capacity. Hence, this study could open a new way to address the classic issues in the load-bearing capacity of asphalt airport pavements and provide a new reference for their safe estimation and rational design. [ABSTRACT FROM AUTHOR]

We evaluate seismicity and tectonics along the San Andreas Fault (SAF) in southern California to elucidate ongoing near‐field crustal deformation processes. The principal slip surfaces (PSSs) or the fault core that accommodate major earthquakes, form the boundary between the tectonic plates. We analyze seismicity catalogs extending back to 1857, 1932, and 1981 with progressively improved magnitude of completeness and spatial resolution. The 1857 to present statewide catalog that is complete at M5.5+ documents minimal aftershock activity for the Mw7.9 1857 and 1906 Mw7.8 San Francisco earthquakes. The higher quality 1932 and 1981 catalogs show that the PSSs (the rupture zone) of the 1857 Mw7.9 Fort Tejon earthquake exhibits remarkable seismic quiescence both in the core and in the adjacent extended‐damage zone. Further south, the fault core is still aseismic but the shape of the SAF is more complex, and the rate of adjacent seismicity is much higher. This fault complexity and the seismicity rate are larger the more the strike of the SAF deviates from the Pacific plate velocity‐vector direction. The focal mechanisms of the SAF adjacent earthquakes are also heterogeneous and rarely have strikes and dips that are consistent with slip on the nearby PSSs. We infer that the southern SAF is locked, and a lack of seismicity at the core of the fault may be a standard feature of faults that almost exclusively accommodate high‐slip rates by producing major earthquakes. Correspondingly future aftershock sequences of major earthquakes on the southern SAF will likely have below average aftershock productivity. Plain Language Summary: The fast‐moving San Andreas Fault (SAF) that runs up the spine of California from the Salton Sea to Cape Mendocino, forms the plate boundary between the Pacific and North America plates. It has accommodated California's two largest earthquakes, the 1857 Mw7.9 Fort Tejon and the 1906 Mw7.8 San Francisco, which ruptured the fault for hundreds of kilometers. We focus on analyzing the seismicity of the southern SAF from 1857 to present. Almost no small earthquakes occur along the core of the southern SAF, from south of Parkfield to the Salton Sea. To the north, the 1857 Mw7.9 earthquake was followed by relatively few immediate aftershocks, and since 1932 this section of the fault has been very seismically quiescent. To the south of the 1857 rupture, the rate of extended‐damage zone seismicity inversely correlates with the SAF strike deviation from the Pacific plate vector relative to the SAF strike. In particular, the east‐west striking 28 km long Mill Creek segment may impede SAF slip, which results in abundant off‐fault seismicity and transfer of tectonic strain into the eastern California shear zone and the Peninsular Ranges. Key Points: The near‐field seismicity of the southern San Andreas Fault (SAF) is limited to the adjacent extended‐damage zone and mostly absent from the fault coreStep changes in the 95% depth and in the texture of seismicity depth distribution likely define the presence of the SAF fault coreSeismicity rate in the damage zone positively correlates with SAF deviation from Pacific plate vector except in the quiescent 1857 rupture [ABSTRACT FROM AUTHOR]

This paper presents the effect of the complex strain state resulting from the asymmetric rolling of TRB products on the changes and distribution of the stress state in the material. The evaluation of the stress state in the material was based on measurements of the magnetoelastic parameter (MP) using the Barkhausen magnetic noise method. The key characteristics of the material under study that enabled the use of changes in the MP parameter to assess the stress state were ferromagnetism and a lack of texture. The first of these enabled the detection of the magnetic signals produced when a magnetic field is applied to the material, causing magnetic domains to align and sudden changes in magnetization. On the other hand, the absence of texture in the material precluded the occurrence of magnetocrystalline anisotropy, which could disturb the results of measurements of the magnetoelastic parameter in the material. In order to determine these features in the material under study, its chemical composition was determined, and a phase analysis was carried out using the X-ray diffraction method. The results of these tests showed the possibility of determining the stress state of the material by means of changes in the values of the MP parameter. On this basis, it was shown that in the TRB strips studied, there is a complex state of stress, the values of which and the nature of the changes depending on the direction of the measurements carried out, as well as on the amount of rolling reduction in the studied area of the strip. [ABSTRACT FROM AUTHOR]

The National Airport Pavement Test Facility (NAPTF) in USA obtained the strain and deformation data of the asphalt airport pavement numbered as Track 3 under the wheel load traveling in the north area of Construction Cycle 7 (CC7). But, the classic theories and methods still could not find out the definite and essential working characteristics, such as the starting point of the asphalt pavement’s failure process and the ending point of the normal working process. This study reveals the essential working characteristics of the asphalt airport pavement by modeling the tested strain and deformation data based on structural state-of-stress theory. Firstly, the tested data are modeled as state variables to build the state-of-stress mode and the parameter characterizing the mode. Then, the slope increment criterion detects the mutation points in the evolution curve of the characteristic parameter with a wheel load traveling number increase. Correspondingly, the mutation features are verified by investigating the evolution curves of the state-of-stress modes. The mutation points define the failure starting point and the elastoplastic branch (EPB) point in the working process of the asphalt airport pavements. The strain state-of-stress mode (Δεt) and characteristic parameters (Ej and Φj) presented an obvious mutation feature around the EPB point; in addition, the deformation state-of-stress mode (ΔDt) showed that the total deformation of the pavement changed evidently before and after the failure starting point, and the characteristic parameters (Ej and Φj) also presented an obvious mutation feature around the failure starting point, so both characteristic points could address the classic issues in the load-bearing capacity of asphalt airport pavements. Furthermore, the EPB point could be directly taken as the design point, and the failure starting point could be taken as the limit-bearing traffic capacity. Hence, this study could open a new way to address the classic issues in the load-bearing capacity of asphalt airport pavements and provide a new reference for their safe estimation and rational design.

Abstract—A method is described for constructing a strain-hardening diagram (SHD) for ChS68-ID cladding steel in the unirradiated state using the results of compressive tests of circular specimens in the longitudinal direction of a pipe to low strains in order to construct the initial section of the diagram and tensile tests to failure of preliminarily ovalized specimens to construct the section of the SHD corresponding to large strains. The approximation coefficients of the SHD model are found by minimizing the root-mean-square deviation of the experimental data from the calculated ones. Finite element analysis of the state of stress in the cladding made of ChS68-ID steel in the unirradiated state using the obtained SHD demonstrates good convergence of the estimated strength properties with those obtained experimentally and a significant difference in the plastic shear strains. [ABSTRACT FROM AUTHOR]

Abstract—A finite element simulation of the state of stress in the femur–condylar prosthesis biotechnical system is performed, and its mechanical behavior is analyzed. The metallic components of the endoprosthesis (implant) are made of a VT6 titanium alloy, and the plateau of the tibial component is made of ultrahigh-molecular-weight polyethylene. The stresses in the bone structures and the most severely loaded components of the endoprosthesis are calculated at a functional load of 3300 N. A high degree of similarity of the biomechanical behavior of the biotechnical system (with the endoprosthesis) to the behavior of a healthy femur has been established. The stresses and strains of all components of the biotechnical system are shown not to exceed their critical values. The calculation results made it possible to predict the operational capability and reliability of the endoprosthesis components under static and cyclic loads, the wear resistance of the mobility unit, and the reliability of the cement mantle. [ABSTRACT FROM AUTHOR]

Fault plane solution is one of the most important tools to determine the orientation of the stress field. The focal mechanism of earthquakes can be applied to determine the direction of rupture propagation, the structure of the fault and the stress field of the region. Dorouneh fault is the largest fault in Iran after the main Zagros fault with about 800 km length. The purpose of this study is to investigate the seismicity, the stress fields and the focal mechanism of earthquakes that have occurred across the three main segments western, middle and eastern parts of the Dorouneh fault. Therefore, the calculation of the focal mechanism is performed using the P-wave first-motion polarity. Also the stress situation of the events and the recognition of fault planes are presented in this research. Along this fault, the blocks have moved in both left and right directions, but certainly one of its last movements has had a right lateral motion. In this study, the waveforms recorded at the seismic stations of the National Seismological Center of Tehran University (IRSC), the National Center of Broadband Seismic Network of Iran belong to the International Institute of Earthquake Engineering and Seismology (IIEES) and seismic stations of Seismological Research Center at the Ferdowsi University of Mashhad were used. At first, the waveforms of each seismic event were combined with each other, and then the relocation of the events were determined based on new data set of this study (Figure 2). A number of high quality earthquake with a magnitude of more than 3 and an average depth of 14 km have been selected (their list is presented in table1) to calculate the fault plane solution. In order to calculate the mechanism of the recent earthquakes in the Khorasan region, interesting results have been obtained based on several methods (Assar Enayati, 1400). One of the common methods for estimating the mechanism of earthquakes, especially earthquakes with small magnitudes and at close distances from the epicenter, is the polarization of the first arrival of the P wave. Due to the dependence of the amplitude and polarization of the P wave on the focal mechanism, by determining the polarization of the first arrival of the seismic phase, the earthquake focal mechanism can be calculated. The results of focal mechanism solutions for significant events around Dorouneh fault show mostly left lateral strike slip motion which is consistent with the tectonic setting of the region. The difference in the focal mechanism of the events in the eastern and western parts of the fault is justified by the northward movement of the Lut block. The integration of data shows high accuracy in calculating the focal mechanism and more certainty about the results. Therefore, in the direction of the Dorouneh fault, the movements are both left-handed and right-handed from the seismic situation. The change in thefocal mechanism obtained from the seismic results, considering the stress axes changes, can represent the second and third order stress fields that balance the stress in this area today. The second-order stress can be related to continental rifting, isostasy adaptation, topography and deglaciation, and the third-order stress field can be related to the local stress source on a scale smaller than 100 km, which is influenced by the structural geometry, and interference between fault systems, topography and local density difference (Sheikh-ul-Islami et al., 2021). [ABSTRACT FROM AUTHOR]

This paper presents the effect of the complex strain state resulting from the asymmetric rolling of TRB products on the changes and distribution of the stress state in the material. The evaluation of the stress state in the material was based on measurements of the magnetoelastic parameter (MP) using the Barkhausen magnetic noise method. The key characteristics of the material under study that enabled the use of changes in the MP parameter to assess the stress state were ferromagnetism and a lack of texture. The first of these enabled the detection of the magnetic signals produced when a magnetic field is applied to the material, causing magnetic domains to align and sudden changes in magnetization. On the other hand, the absence of texture in the material precluded the occurrence of magnetocrystalline anisotropy, which could disturb the results of measurements of the magnetoelastic parameter in the material. In order to determine these features in the material under study, its chemical composition was determined, and a phase analysis was carried out using the X-ray diffraction method. The results of these tests showed the possibility of determining the stress state of the material by means of changes in the values of the MP parameter. On this basis, it was shown that in the TRB strips studied, there is a complex state of stress, the values of which and the nature of the changes depending on the direction of the measurements carried out, as well as on the amount of rolling reduction in the studied area of the strip.

Abstract—The state of stress in the femur–hip stem biotechnical systems with uncemented and cemented use for revision arthroplasty is calculated using a finite element method and the ANSYS software package. 3D finite element models are developed for these systems and a healthy intact femur. The stress levels in bone structures and the deformation characteristics of the system models at a load of 3300 N are calculated. The high degree of similarity of the biomechanical behavior of all models indicates the operability of the stems of both designs. The stress levels in the cemented- and uncemented-implant stems are found to be 2–3 times lower than the fatigue limit of the initial deformed semifinished product made of a VT6 titanium alloy. This fact indicates the reliability of the implant stems of the proposed designs. [ABSTRACT FROM AUTHOR]

Abstract—The influence of residual welding stresses on the probability of brittle fracture of a welded joint with a crack is investigated. The elastoplastic deformation of the material at the crack tip under the action of tension and a residual stress field is studied. The state of stress is analyzed by a finite element method with allowance for the elastoplastic properties of the material. The random nature of the field of residual welding stresses is taken into account using a statistical modeling method (Monte Carlo method). A method is developed to take into account residual stresses in brittle fracture resistance calculations of welded structures. The results obtained are used to estimate the minimum temperature at which the first loading of a welded structure with a cracklike defect can be carried out. [ABSTRACT FROM AUTHOR]

Seismic profiling in a coal seam enables the determination of anomalous changes in the P-wave velocity compared to reference velocity at a specific mining depth, indicating potential stress changes. This information can improve the coal exploitation processes in advance at greater depths, especially in seismic hazard areas. This study aims to update the empirical mathematical formula for calculating reference P-wave velocities in coal seams by including new data measured at greater depths. The research was performed at the Zofiówka Coal Mine in the geological and mining conditions of the Upper Silesian Coal Basin in Poland. The analysis involved the study of 276 velocity values including 24 new velocity values measured at depths ranging from 704 to 1073 metres in the period 2009-2024. Through regression analysis, the standard model was modified. The new model provides more reliable velocity anomaly calculations and accurately reflects the geomechanical conditions at greater depths in the Zofiówka Coal Mine. The calculation procedure can be utilised to develop velocity models for various geological and geomechanical conditions in underground mines that exploit coal seams at continuously increasing depths., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

The main question of this paper is the stress-strain state prediction of the vertical shaft’s combined lining located at the interface of two layers of dolomite and salt. The study predicts geomechanical processes at the contact of the dolomite layer and the salt layer in the vicinity of the vertical shaft’s expanded section, taking into account the operating life of a vertical shaft is equal to 50 years. The results combined lining’s stress-strain state, represented as a four – layer medium, where the external layer is concrete, and the three inner layers are used to account for the heterogeneity of cast-iron tubing and are compared with the results received when taking into account the pipe structure. The solution of the problem was carried out in a three-dimensional statement. The calculation of the tubing lining, considering its actual geometry, will increase the accuracy of the forecast of the stress state of the lining, which in turn will favourably affect the justification of its parameters.

The study was aimed to identify the features of the formation and regularities of manifestation of faults in the platform environment applying the tectonophysical approach to the study of the structure of the Tambey hydrocarbon deposit (northern Yamal), largest in the West Siberia. Such research is important in the oil and gas industry at the present stage of transition from the exploitation of declining unique and large deposits to exploration and exploitation of deposits of complex structure. The tectonophysical approach was applied consistently in three levels of research. Initial consideration was given to regular trends in the structure of the platform cover in the context of general tectonophysical ideas of disjunctive faults, their inner structure and formation features. Then, the identification of a network of large fault zones has been done at the regional level for the northern Yamal on the basis of the lineament analysis of the relief and optical modeling, three main stages of its formation have been reconstructed, and there have been identified the features of the state of stress, among other factors determining the Tambey deposit contours in three areas – western and northern Tambey and Tassyi. Finally, based on tectonophysical interpretation of 3D seismic attribute analysis data and elastoplastic modeling experiment results, for the northern Tambey area at the local level there were identified the faults zones, the features of their structures in rheologically stratified unit, and the paragenetic relationship with the regional-level structures. The study has shown that the structure of the sedimentary cover, whose formation is tectonically influenced by the adjacent mobile belts, is zone-block. It reflects the zone-block structure of the basement, though, in contrast, is not represented by narrow main-fault planes (1st-order faults). The blocks in the cover contact along rather wide zones, the inner structure of which corresponds to the early stages of faulting and is represented by a dense network of the 2nd-order fractures and faults. The fault zones are characterized by an inhomogeneous – segment – structure which is determined by an initially irregular development of deformations and complicated by rheological stratification of the sedimentary cover. Fault segments in relatively brittle rocks (sandstones) are composed of long faults whereas in more ductile (clayey) varieties these are wide parts of concentration of small faults and fractures. A style of the zone-block structure and the types of dynamic environments of its formation might be specific in different regions. The application of tectonophysical approach to the analysis of the geological-geophysical information, obtained for certain deposits, will make it possible to identify the structural conditions for hydrocarbon accumulation and migration in the sedimentary cover which is essential to choose an effective method of deposit exploitation.

Tectonic fracturing of the Mesozoic and Cenozoic structures was studied in the Northern Priokhotie (Magadan region). The cataclastic analysis method and the statistical method of fracture density analysis were used to reconstruct their state of stress. It is revealed that the folded structures of the Arman’-Viliga synclinorium are subjected to horizontal shearing; the axis of maximum compression is sublatitudinal (azimuth 67°, angle 12°); extension is submeridional (azimuth 161°, angle 19°). In the Uda-Murgal volcanic arc, horizontal extension with shear takes place; the compression axis is directed to NW (azimuth 259°, angle 29°), and the extension axis to NE (azimuth 152°, angle 26°). In the Okhotsk-Chukotka volcanogenic belt, volcanic structures are in the field of varying tectonic stresses, from predominant horizontal extension to horizontal shear. The Cenozoic intermontane depressions of the Miocene – Pliocene ages are subjected to horizontal shear; the compression axis is directed to NE (azimuth 214°, angle 29°), and the extension axis to NW (azimuth 121°, angle 4°). The results of the comparative analysis of the stress states in the above-mentioned areas reliably show that the diversity of the stress state types is statistically related to the structural positions of the studies sites. Such diversity cannot be explained by an influence of active faults, or by any consecutive superposition of deformations at different stages, despite the fact that the deformations have complicated the observed pattern of the stress states. We conclude that each subsequent geodynamic stage only introduced additional elements into the previous structure, but did not completely transform it.

Plants' resistance to stress factors is a complex trait that is a result of changes at the molecular, metabolic, and physiological levels. The plant resistance strategy means the ability to survive, recover, and reproduce under adverse conditions. Harmful environmental factors affect the state of stress in plant tissues, which creates a signal triggering metabolic events responsible for resistance, including avoidance and/or tolerance mechanisms. Unfortunately, the term 'stress resistance' is often used in the literature interchangeably with 'stress tolerance'. This paper highlights the differences between the terms 'stress tolerance' and 'stress resistance', based on the results of experiments focused on plants' responses to drought. The ability to avoid or tolerate dehydration is crucial in the resistance to drought at cellular and tissue levels (biological resistance). However, it is not necessarily crucial in crop resistance to drought if we take into account agronomic criteria (agricultural resistance). For the plant user (farmer, grower), resistance to stress means not only the ability to cope with a stress factor, but also the achievement of a stable yield and good quality. Therefore, it is important to recognize both particular plant coping strategies (stress avoidance, stress tolerance) and their influence on the resistance, assessed using well-defined criteria. [ABSTRACT FROM AUTHOR]

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Shot peening forming (SPF) is an effective technological technique for forming a contour of double curvature of large-sized low-rigid parts. This technique, in combination with press bending or bending–rolling, makes it possible to form surfaces of double alternating and (or) sign-constant curvature. To date, the Russian technology of combined forming has been tested in production and has special equipment and a number of methods for determining the operating process parameters. However, the existing methods have assumptions related to the specific features of processing with contact-type shot peening devices, which lead to a significant decrease in the calculation accuracy. The influence of technological heredity during the formation of the state of stress (SOS) of a workpiece requires an additional study. It is necessary to develop effective technological methods for forming sections of double-curvature casing, the processing of which takes much time due to high rigidity. This article presents the results of finite element simulation of the SPF process on contact-type installations, and they can be used to build high-precision methods for determining the operating parameters taking into account the specific features of processing and the initial SOS (technological heredity) formed at the previous stages. The bending–rolling and SPF processes are simulated using the LSTC LS-Dyna Version R10 finite element analysis environment with model generation in the MATLAB environment. [ABSTRACT FROM AUTHOR]

The X-ray diffraction technique for determining residual stresses in construction steels has been commonly used in the international scientific community for decades. Taking advantage of the concepts on which the technique is based, the authors have previously calibrated and used the technique for the in situ determination of the stress states of metallic structures in service. This article presents an advance in the latter utility by means of the laboratory calibration of the X-ray diffraction technique in corrugated steel. The interaction between radiation and steel is complex, so, in the scientific community, it is considered pertinent to resort to empirical and experimental calibration processes. Two bars of corrugated steel were subjected to increasing tensile loads. The load states introduced in the testing machine were compared with those determined by X-ray diffraction. The correlation between the values of the loads applied and those determined by the proposed technique is excellent. The experimental conditions of the calibration tests are precisely detailed so that they are easily reproducible. This work represents a necessary first step in employing the technique in the buildings or civil works. [ABSTRACT FROM AUTHOR]

The PAM-Stamp 2G software package is used to simulate the tool bending of a workpiece made of an AMg5 aluminum alloy with and without taking into account the heat-affected zone (HAZ) formed during laser cutting of a sheet. The option of calculating welded workpieces is adapted to describe the HAZ. The state of stress in the workpiece during bending at various bending radii is analyzed with allowance for various HAZ widths. The influence of HAZ up to 4.5 mm wide on the workpiece thickness during bending is found to be insignificant. [ABSTRACT FROM AUTHOR]

The state of stress in locked-coil rope elements is subjected to finite element simulation under joint tension and torsion. The axial forces and torques in the cross sections of the layers are found to be redistributed when a rope turns under an external torque, which leads to a decrease in the safety factor of the rope, a violation of the compatibility of the axial and radial displacements of the layers, and a violation of the structural integrity of the rope in the form of breaks in the outer layer wires. [ABSTRACT FROM AUTHOR]

A variety of geophysical methods and analytical modeling are applied to determine the rockburst hazard in Polish coal mines. In particularly unfavorable local conditions, seismic profiling, active/passive seismic tomography, as well as analytical state of stress calculating methods are recommended. They are helpful in verifying the reliability of rockburst hazard forecasts. In the article, the combined analysis of the state of stress determined by active seismic tomography and analytical modeling was conducted taking into account the relationship between the location of stress concentration zones and the level of rockburst hazard. A longwall panel in the coal seam 501 at a depth of ca.700 m in one of the hard coal mines operating in the Upper Silesian Coal Basin was a subject of the analysis. The seismic tomography was applied for the reconstruction of P-wave velocity fields. The analytical modeling was used to calculate the vertical stress states basing on classical solutions offered by rock mechanics. The variability of the P-wave velocity field and location of seismic anomaly in the coal seam in relation to the calculated vertical stress field arising in the mined coal seam served to assess of rockburst hazard. The applied methods partially proved their adequacy in practical applications, providing valuable information on the design and performance of mining operations. [ABSTRACT FROM AUTHOR]

New advance in modelling of the machining process is of great significance to improve component performance and manufacturing efficiency. This includes the material constitutive model and the approach used to describe the field flow of the material in cutting. In this study, a 3D model of high speed machining (HSM) of Ti6Al4V titanium alloy is developed. The coupled Eulerian-Lagrangian (CEL) approach was used to simulate the proposed cutting model. This cutting model includes a proposed constitutive model considering the strain hardening, strain-rate, temperature and stress state (e.g., stress triaxiality and Lode parameter) in the material plasticity and damage. This machining model is able to simulate the phenomenon of material side flow, which results in a larger chip width when compared to the width of cut and the lateral burr formation. The phenomenon of material side flow is validated by experimental results. The distribution of plastic strain and stress state shows that the workpiece transforms from plane strain state in middle surface to plane stress state in lateral surface, which finally results in the formation of lateral burr. [ABSTRACT FROM AUTHOR]

Plants’ resistance to stress factors is a complex trait that is a result of changes at the molecular, metabolic, and physiological levels. The plant resistance strategy means the ability to survive, recover, and reproduce under adverse conditions. Harmful environmental factors affect the state of stress in plant tissues, which creates a signal triggering metabolic events responsible for resistance, including avoidance and/or tolerance mechanisms. Unfortunately, the term ‘stress resistance’ is often used in the literature interchangeably with ‘stress tolerance’. This paper highlights the differences between the terms ‘stress tolerance’ and ‘stress resistance’, based on the results of experiments focused on plants’ responses to drought. The ability to avoid or tolerate dehydration is crucial in the resistance to drought at cellular and tissue levels (biological resistance). However, it is not necessarily crucial in crop resistance to drought if we take into account agronomic criteria (agricultural resistance). For the plant user (farmer, grower), resistance to stress means not only the ability to cope with a stress factor, but also the achievement of a stable yield and good quality. Therefore, it is important to recognize both particular plant coping strategies (stress avoidance, stress tolerance) and their influence on the resistance, assessed using well-defined criteria.

Heating of a thin metal film on a semiconductor surface and the corresponding state of stress of the near-contact region are considered. The stress estimation procedure in case of the local pulsed heating of a metallized region on the semiconductor surface is described. The theoretical and experimental sizes of the deformed silicon substrate region are compared with each other. An experiment is carried out using rectangular current pulses. The stress–strain region, which depends on the electric pulse duration and amplitude, is estimated. Experimental evidence shows a strong heterogeneity of the metallization track after pulse passage. [ABSTRACT FROM AUTHOR]

The influence of the state of stress on the dynamic recrystallization characteristics and the deformation behavior of the VT5-1 α-titanium alloy during compression at temperatures of 800 and 900°C in the strain rate range 4.0 × 10–5–6.0 × 10–3 s–1 is studied. The effects of the temperature, the strain rate, and the hydrostatic component of the state of stress on the fine structure, the texture, the grain size, and the grain misorientation distribution are found. The grain size and the intensity of dynamic recrystallization during compression at 900°C are shown to become strongly dependent on the strain rate. An increase in the hydrostatic component of the stress tensor decreases the average grain size and the volume fraction of recrystallized grains. [ABSTRACT FROM AUTHOR]

The deformation characteristics of silica fabric with a thermal barrier coating, which is used for the production of the ballute-type aerobrake of a descent module, are estimated. A rubberized fabric strip is subjected to uniaxial tensile tests to failure. Various finite-element simulation approaches to the deformation of the fabric are considered. [ABSTRACT FROM AUTHOR]

This paper studies the failure mechanism during the structural progressive collapse process of a spatial steel frame with concrete floor by applying structural state of stress theory. Firstly, structural state of stress is modeled by generalized strain energy density (GSED) derived from the experimental strain data. Then, the Mann-Kendall criterion is used to detect the leap characteristic of structural state of stress from the GSED sum-load curve. Next, two state of stress characteristic parameters, average sectional strain and generalized bending strain, are proposed to characterize both axial and bending deformation forms and to reflect the structural working behavior. As a result, the modeling and judgment of structural state of stress reveal the structural progressive failure characteristics. Furthermore, the inner failure mechanism of the steel frame is further revealed by analyzing its internal force redistribution related to the membrane action and catenary action. Finally, the coordinative working performance of the steel frame is investigated in the significance of the self-adaption reflected in the state of stress uniformity and balance. • Experimental strain data is modeled as GSED values to express the stressing state of frame model. • The definition of failure load is updated at the starting point of the frame model's failure process. • Structural state of stress analysis on the frame model reveals its progressive failure characteristics. • It reveals the effects of membrane action and catenary action on the frame model's state of stress feature. • It models and demonstrates the coordinative working performance between beam, column and floor. [ABSTRACT FROM AUTHOR]

Vibration‐based stress state identification method for iron and steel truss structures The assessment of the load‐bearing capacity of existing iron and steel truss structures is significantly dependent on the determination of the axial forces and corresponding stresses in axially loaded structural members. The axial forces in truss structures can be estimated by static calculations if accurate information about the structure and external loads are known. However, the stress condition for historical constructions can usually only be estimated inaccurately due to uncertainty in the assumptions of a static model. As an alternative to static calculations, non‐destructive measurement based techniques can be used. The newly developed methodology is based on vibration measurements and the finite element model updating. The member forces of the truss members can be calculated by means of an analytically based algorithm and a comparison between the numerically computed and experimentally identified natural frequencies and mode shapes of the truss structure as well as of selected individual members. For the tested structural systems, the identified axial forces by the proposed methodology agree well with the experimentally measured axial forces at different stress states. Furthermore, practical recommendations for the preparation of a measurement concept and development of design strategies for in‐situ investigations and safety assessment of existing iron and steel truss structures are given. [ABSTRACT FROM AUTHOR]

Three prolific earthquake swarms and numerous smaller ones have occurred since 1980 in the Mesozoic igneous plutonic rocks of the Perris block of the Peninsular Ranges, Southern California. The major swarms occurred in 1980–1981, 1983–1984, and 2016–2018, with the latest swarm still ongoing. These swarms have no clear mainshock, with the largest events of ML 3.6, ML 3.7, and Mw 4.4. Each successive swarm had larger cumulative seismic moment release with about 314 and 411 events of M ≥ 1.5, while the third swarm has produced about 451 events of M ≥ 1.5 (as of September 2018). The concurrent strike‐slip faulting occurred on north to northwest striking planes but with no orthogonal northeast trending seismicity alignments. These shallow swarms are probably driven by intrablock Pacific‐North America plate boundary stress loading of the two bounding major late Quaternary strike‐slip faults, the Elsinore and San Jacinto faults. The state of stress within the Cahuilla Valley pluton has a ~40° angle between the maximum principal stress and the average trend of the swarms, suggesting that migrating pore fluid pressures aid in the formation and growth of zones of weakness. These swarms, which last more than 600 days each, exhibit clear bilateral spatial migration for distances of up to ~7–8 km and reach their full length in about 20 months. The slow spatial‐temporal development of the swarms corresponds to a fluid diffusivity of 0.006 to 0.01 m2/s, consistent with very low permeability rocks as expected for this block. There is no geodetic or other evidence for a slow slip event driving the swarms. Plain Language Summary: There have been three unusual seismicity swarms in the Cahuilla Valley, Peninsular Ranges, over the last 40 years: 1980–1981, 1983–1984, and 2016–2018, with the latest still ongoing. They occurred within granite rocks that underlie the Cahuilla Valley pluton. The first two lasted for about 2 years, and the current swarm is still ongoing more than 2.5 years after it began. These swarms differ from mainshock‐aftershock sequences because the largest events occur months after the swarm initiation event. These swarms are probably driven by plate boundary stress loading of the two bounding major late Quaternary strike‐slip faults, the Elsinore and San Jacinto faults, and aided by changes in pore fluid pressures. Key Points: Since 1980, three prolific natural earthquake swarms occurred between the Elsinore and San Jacinto faults, in the central Peninsular RangesThese swarms are driven by interseismic plate boundary strain rates and modulated by pore fluid pressure in low‐permeability plutonic rockShallow depths, absence of mapped faults, and nonlinear seismic moment release suggest concurrent slip on foliations in the plutonic rock [ABSTRACT FROM AUTHOR]

The tensile deformation behavior of the steel/CFRP (carbon fiber reinforced plastic) adhesive joint is studied. The evolution of the deformation fields in the surface layer of CFRP is investigated by digital image correlation. The specimen is shown to fail along the adhesive joint at a strain of 0.17%. [ABSTRACT FROM AUTHOR]

The article describes a method yielding approximate analytical solutions under the theory of elasticity for a set of interacting arbitrarily spaced shear fractures. Accurate analytical solutions of this problem are now available only for the simplest individual cases, such as a single fracture or two collinear fractures. A large amount of computation is required to yield a numerical solution for a case considering arbitrary numbers and locations of fractures, while this problem has important practical applications, such as assessment of the state of stress in seismically active regions, forecasts of secondary destruction impacts near systems of large faults, studies of reservoir properties of the territories comprising oil and gas provinces.In this study, an approximate estimation is obtained with the following simplification assumptions: (1) functions showing shear of fractures’ borders are determined similar to the shear function for a single fracture, and (2) boundary conditions for the fractures are specified in the integrated form as mean values along each fracture. Upon simplification, the solution is obtained through the system of linear algebraic equations for unknown values of tangential stress drop. With this approach, the accuracy of approximate solutions is consistent with the accuracy of the available data on real fractures.The reviewed examples of estimations show that the resultant stress field is dependent on the number, size and location of fractures and the sequence of displacements of the fractures’ borders.

Abstract Ti6Al4V titanium alloy is widely used in aero-engines due to its superior performance. However, as a difficult-to-cut alloy, it induces short cutting tool life and poor surface integrity. To improve these process outcomes, numerical simulations are of importance. The predictive ability of such simulation depends on the accuracy of the constitutive model which describes the work material behavior under loading conditions specific to metal cutting. Therefore, the focus of this paper is the formulation of a constitutive model to be used in the orthogonal cutting simulation of Ti6Al4V. The distinguished feature of this model is its simplicity, accounting for the strain-rate and state of stress effects in the work material deformation and fracture. The model coefficients were identified using mechanical tests and numerical simulations with specially-designed test specimens to cover a wide range of strain-rates and state of stress. Orthogonal cutting simulations were performed and the obtained results were compared with those measured. [ABSTRACT FROM AUTHOR]

The main oil and gas reserves around the world are found in regions containing evaporitic rocks. Owing to their low porosity and low permeability these rocks provide favorable conditions for hydrocarbon trapping, increasing the probability of success in oil and gas exploration. Salt rocks exhibit time-dependent strain behavior when submitted to deviatoric stresses. This behavior is described by creep constitutive laws based on deformation mechanics. One of the major challenges in modeling stress states in sedimentary basins in the presence of salt structures is to predict the magnitude of stress perturbations around salt bodies. This work presents a geo-mechanical approach to take into account the specific weight variation throughout the lithology and the effects of buoyancy in the resulting forces on the interface salt-body/formation. Modeling is driven by the fact that salt bodies cannot sustain deviatoric stresses. Numerical analyses using the Finite Element Method under plane strain conditions provide the results for the comparison of the methodologies found in the literature with the one proposed by the authors. Two synthetic models with salt dome structures are investigated. The proposed approach provided more realistic stress fields in the vicinity of salt structures. [ABSTRACT FROM AUTHOR]

This paper presents a computational algorithm allowing the efficient use of high-performance computing resources to solve nonlinear problems of continuum mechanics using FEM. The algorithm is suitable for solving static problems and tasks of estimating lifetime of structures in cases where the load is defined by the load spectrum. The complexity of the problem increases significantly in the case of nonlinear problems. The principle of the stress superposition cannot be used in that case. For each loading mode a separate FE analysis must be made. A quick and efficient procedure for evaluating the results of mentioned analysis for the static calculation as well as for the estimated life calculation is also presented in this paper. In the presented examples the contact of bodies is used as a source of nonlinearity. The size, shape or position of the contact area is not possible to estimate in contact of bodies. These types of problems are thus highly nonlinear. Programs for the presented algorithms are processed in the program package OCTAVE and calculations using FEM are made in the software ADINA.

The conditions of using a software package for studying the state of stress in the cutting element intended for cold milling of a road coating are considered. The mechanism of designing a 3D model for the cutting element and the choice of failure criteria for the cutting element are described. The state of stress is subjected to graphical analysis at various loads. [ABSTRACT FROM AUTHOR]

The diagnostic inspection used to estimate the technical state of a pipeline is described. The problems of inspection works are listed, and a functional-structural scheme is developed to estimate the state of stress in a pipeline. Final conclusions regarding the actual loading of a pipeline section are drawn upon a cross analysis of the entire information obtained during pipeline inspection. [ABSTRACT FROM AUTHOR]

Assessing the parameters that control the location and geometry of magma paths is of paramount importance for the comprehension of volcanic plumbing systems and geo-hazards. We analyse the distribution of 1518 monogenic and polygenic volcanoes of Miocene-Quaternary age of the Central Volcanic Zone of the Andes (Chile-Bolivia-Argentina), and reconstruct the magma paths at 315 edifices by analysing the morphostructural characteristics of craters and cones. Then we compare these data with outcropping dykes, tectonic structures and state of stress. Most magma paths trend N–S, NW–SE, and NE–SW, in decreasing order of frequency. The N–S and NW–SE paths coexist in the northern and southern part of the study area, whereas N–S paths dominate east of the Salar de Atacama. Outcropping dykes show the same trends. The regional Holocene stress state is given by an E–W greatest horizontal principal stress. N–S and NNE–SSW reverse faults and folds affect deposits of 4.8, 3.2 and 1.3 Ma BP, especially in the central and southern study areas. A few NW–SE left-lateral strike-slip faults are present in the interior of the volcanic arc, part of which belong to the Calama-Olacapato-El Toro fault. The volcanic chain is also affected by several N–S- and NW–SE-striking normal faults that offset Pliocene and Quaternary deposits. The results indicate different scenarios of magma-tectonic interaction, given by N–S normal and reverse faults and N–S fold hinges that guide volcano emplacement and magma paths. Magma paths are also guided by strike-slip and normal NW–SE faults, especially in the northern part of the study area. Zones with verticalized strata, with bedding striking NE–SW, also acted as preferential magma paths. These data suggest that at convergence zones with continental crust, shallow magma paths can be more sensitive to the presence and geometry of upper crustal weakness zones than to the regional state of stress. [ABSTRACT FROM AUTHOR]

In the automotive sector, dual phase (DP) steel grades have been increasingly used for various car body parts due to their good combination of strength and formability. To control mechanical and fracture characteristics of the DP steels, effects of martensitic phase fraction, morphology, and phase distribution must be understood. In this work, DP steel sheets with different martensitic phase fractions and ferritic grain sizes were produced through the intercritical annealing process. Likewise, FE simulations of 2D representative volume elements (RVEs) based on real micrograph were performed for all generated DP microstructures. Flow behaviors of single individual phases in the DP steels were described by a dislocation theory and local chemical compositions. Calculated stress-strain responses were verified with experimental results from tensile tests. Subsequently, stretch-forming tests under different states of stress using the Nakajima samples were carried out for the examined DP steels. Micromechanics RVE models were then applied to predict failure occurrences in the DP microstructures by considering plastic strain instability. Influences of morphologies and properties of constituent phases on localization due to incompatible deformation between martensite and ferrite were discussed with regard to governing stress states. [ABSTRACT FROM AUTHOR]