Rupture Behavior Research Articles

General theory of diaphragm rupture in a shock tunnel

As the flow field starting device is in a shock tunnel, the rupture performance of the diaphragm directly influences the successful formation of the shock wave. The general theory of diaphragm rupture in shock tunnels is proposed first in this paper. The reasons for diaphragm rupture are explained fundamentally. The existing ideologies on diaphragm rupture are unified, and two hypotheses with corresponding methods are introduced. In the ideal diaphragm, diaphragm rupture pressure or rupture time can be predicted by considering the diaphragm opening as a throat through a diaphragm opening aperture. In the non-ideal diaphragm, the control of diaphragm rupture pressure can be realized by considering nominal rupture stress and grooved thickness. The correctness of the general theory of diaphragm rupture is proved through argumentation and based on experimental results of the literature. The general theory of diaphragm rupture can be used to predict the diaphragm rupture behavior of any shock tunnel worldwide and avoid the risk of shearing of petals on the diaphragm caused by the impact load. A new system of diaphragm rupture theory is constituted, and it is of significant importance for the efficient operation of shock tunnel equipment.

Unravelling the dominant influence of microsegregation on creep rupture behaviour of additively manufactured inconel 718

This investigation focuses on unravelling the dominant influence of microsegregation and microstructure altered due to heat treatment cycle variation on creep rupture behaviour of additively manufactured Inconel 718 (AM-IN718). Two microstructural variants differing in the fraction of recrystallized grains while δ-phase being absent, were produced. A typical heat treatment (HT) cycle includes the stress-relieving of the as-built specimens at 980 °C, followed by solution treatment at 1080 °C (STA1080, a partially recrystallized microstructural variant) or 1150 °C (STA1150, a fully recrystallized microstructural variant), and double ageing (soaking at 720 °C for 8h and subsequent furnace cooling, followed by 8h at 620 °C and air cooling).Detailed microstructural characterization of two microstructural variants through correlative microscopy revealed a prevalent existence of Nb-rich precipitate-free zones (PFZ) in STA1080 than in STA1150. Creep characterization of the two microstructural variants in the temperature range of 625–675 °C and at 500–750 MPa demonstrated superior creep resistance in STA1150. The correlation of kinetic analysis and comprehensive post-deformation microstructural characterization suggests grain boundary cavitation as the main damage/softening mechanism and the reason for the difference in creep rupture behaviour between the two microstructural variants. The long-term exposure heat treatment methodology demonstrates that PFZs are the major influencing factor responsible for microsegregation-dependent creep rupture behaviour. Interestingly, the presence of the δ phase within PFZs appeared to retard cavity coalescence and failure during creep, despite its usual detrimental role in creep resistance.

Multi-scale influences of as-cast microstructure heritability on intermediate/high temperature stress rupture behaviors of [111]-oriented Ni-based single crystal superalloy

Multi-scale influences of as-cast microstructure heritability on intermediate/high temperature stress rupture behaviors of [111]-oriented Ni-based single crystal superalloy

Rupture behaviors of the southern Xianshuihe fault and seismicity around Mt. Gongga: Insights from the 2022 MW 6.6 Luding (China) earthquake sequence

The 2022 MW 6.6 Luding earthquake occurred on the Moxi segment of the Xianshuihe fault at the southeast margin of Tibetan Plateau, China. To assess the seismic potential of the Moxi segment, we examine the rupture process of the mainshock and aftershock sequence, along with historical seismicity. Our preferred slip model inverted from teleseismic body waves and regional GNSS static displacements shows a dominant southeastward rupture consisting of two distinct, prominent slip patches along strike extending by ∼15 km, with a peak slip of ∼2.8 m, approximately balancing the slip deficit since the last major earthquake in 1786. The northern section of the Moxi segment experienced minor coseismic slip, which, together with the significant slip deficits and positive Coulomb failure stress change induced by the 2022 mainshock indicates a high seismic potential. Several aftershock clusters are distributed along or near the Moxi segment, with strike-slip focal mechanisms around the downdip edge of the coseismic slip area at ∼8‐12 km. At the eastern flank of Mt. Gongga, another cluster of normal faulting aftershocks is located at shallower depths of ∼3‐7 km, with high seismicity rate over ∼9 months including two other M5 sequences in January and February 2023. Similar intense shallow normal faulting activity had occurred after the impoundment of the nearby Dagangshan reservoir in 2015. We speculate that some NW-SE trending normal faults were initially developed by the gravitational collapse of Mt. Gongga underneath the eastern flank, further weakened by fluid flow, as supported by the existence of hot springs and water impoundment, and reactivated by the tensional stress change induced by the 2022 mainshock. These results have important implications for assessing the seismic hazard in and around the Moxi segment, and the potential interplay between strike-slip fault and nearby mountain areas.

A Transtensional Fault Zone on the Northeastern Margin of the Tibetan Plateau: Millennial Earthquake Recurrence and High Earthquake Hazard

AbstractThe seismic gaps between ruptures of large earthquakes in tectonically active deformation zones are usually considered to be dangerous areas for future earthquakes. The Western Tianzhu Basin fault (WTBF) with an oblique normal motion is located in the middle of the Tianzhu seismic gap between the M 8.5 Haiyuan and M 8.0 Gulang earthquakes, NE Tibetan Plateau. The faulting activity of the WTBF is key to understanding the seismic hazards of the seismic gap, but it remains poorly constrained. Using satellite images, field investigations, paleoseismic trenching, and radiocarbon dating, we found that the WTBF produced seven paleoearthquakes since ∼8,000 cal. yr BP, with the latest event occurring at 1,005 ± 584 cal. yr BP, yielding an average recurrence interval of 1,102 ± 100 yr and a coefficient of variation of 0.38, indicating that it features a millennial quasi‐periodic recurrence. Based on the comparative analysis of geometry, kinematics, and tectonic activity, we suggest that the Tianzhu seismic gap can be divided into three sections and is characterized by a segmented rupture pattern. Among them, the WTBF and Jinqianghe fault exhibit similar geometry and kinematics and together form the ∼55 km‐long Jinqianghe‐Tianzhu transtensional fault zone (JTTFZ) that is capable of producing earthquakes of Mw 7.2. Given the long elapsed time since the latest event and strong seismogenic potential, it is believed that the JTTFZ poses a high seismic hazard. Our results enhance the understanding of the high seismic hazard in seismic gaps and provide new insights into the seismic rupture behavior in the NE Tibetan Plateau.

High-temperature creep rupture behavior of dissimilar welded joints of RAFM steel and 316L steel by friction stir welding

High-temperature creep rupture behavior of dissimilar welded joints of RAFM steel and 316L steel by friction stir welding

Fault geometry and kinematics at the intersection of the Zemuhe, Daliangshan and Xiaojiang Faults

The complexity of strike-slip fault segmentation affects the initiation, propagation, and termination of earthquake ruptures and the earthquake magnitude. Studying the fault geometry, kinematics, and segmentation provides fundamental knowledge for mitigating earthquake hazards along faults. The Zemuhe, Daliangshan, and Xiaojiang Faults intersect along the eastern boundary of the Tibetan Plateau in the area from Ningnan in Sichuan Province to Qiaojia in Yunnan Province. Although few large earthquakes have occurred on these faults, the relationships between the intersections of these three faults and earthquake rupture behavior in this region are poorly constrained. The interpretation of aerial photographs and detailed field surveys revealed the geometric pattern and fault kinematics in the area of intersection. The distribution patterns and focal depths near the faults were obtained via analysis of seismic data in the area of intersection. The northern segment of the Xiaojiang Fault deviates approximately 25° northwest of Qiaojia, forming a conspicuous bend. The Xiaojiang Fault continues to extend southeast of the Ningnan Basin, where it intersects with the southern segment of the Zemuhe Fault, forming a pull-apart basin approximately 4.5 km wide. The bend and Ningnan pull-apart basin mark the segmented boundary between the Zemuhe Fault and the Xiaojiang Fault, which may prevent the propagation of large earthquake ruptures along the eastern boundary fault. Moreover, the lack of obvious geometric complexity between the Daliangshan Fault and Xiaojiang Fault might hinder the prevention of earthquake rupture propagation. Additionally, our results suggest that different earthquake prevention and disaster reduction measures should be taken for different cities in the region.

Activity and motion characteristics on the southern segment of the Red River fault zone, Yunnan province, China

The longer time for recording large earthquakes on a plate boundary fault, the better that understanding of large earthquake rupture behavior and seismic hazard on the fault zone. However, large earthquakes (M ≥ 7) are rarely recorded on the boundary fault with slow slipping rate, such as the Red River fault zone (RRFZ), which is an important plate boundary fault that marks the southwestern boundary of the Yangtze platform or south China block. There have been no large earthquake records on the southern segments (including the segment in Vietnam) of the RRFZ since historical earthquake records began in 886 AD, except the 1652 Midu M 7 earthquake and the 1925 Dali M 7 earthquake on the northern segment. The southern segment of the RRFZ will not have a large earthquake in the future or as a large earthquake seismogenic zone with a long period of recurrence, remains controversial, in part because of the absence of constraints from geological evidence. This controversial seriously restricts the risk assessment of future large earthquakes on the southern segment of the RRFZ. By careful interpretations of high resolution remote sensing images, in combination with a detailed field geological and geomorphic survey, we found a series of fault valleys and bedrock outcrops from Gasha toYaojie and Yuangjiang to Hekou on the southern segment of the RRFZ. Multiple trench excavation and radiocarbon dating sample analyses show that the mid valley trace in the southern segment of the RRFZ is an active fault. Geological and geomorphic evidence from Gasha to Yaojie and Yuanjiang to Hekou indicate that the mid valley trace in the southern segment of the RRFZ exhibits dip slip and dextral strike slip motion characteristics. This result is inconsistent with those of previous studies that the mid valley trace is purely strike slip. Furthermore, trenches opened on the range front trace in the southern segment of the RRFZ in Ejia are found to still be active, differing from previous studies. Thus, the seismic hazard on the southern segment of the RRFZ should be reevaluated.

Manually directional splitting of in-situ intact igneous rocks into large sheets

This paper presents a directional large-area rock fracturing method. The method had distinctive features compared with other common fracturing methods. The area of the fracturing surface could reach 10–500 m2. The fractured rock was sheet-like in shape, with a thickness of 6–8 cm. The main fracturing tools and procedures used were described in the paper. This paper analysed the reason for controllable and directional (also mode-I) rupturing in rock from the view of fracture mechanics. Counter-intuitively, the fracturing surface of the rock sheet had an angle (approximately 25°) to the loading direction (i.e., the orientation of the maximum principal compressive stress). The rupture behavior was controlled by the relationship between the load and the geometric boundary of the rock. It is found that the fracturing surface can suddenly and rapidly propagate after a certain strike by calculating the energies of the rock sheet. The striking energy could be converted into elastic strain energy, which accumulates in a very-slightly bent rock sheet step by step until exceeds the bearing limit of rock sheet. Most of the stored elastic strain energy was subsequently released in the form of splitting energy, leading to rock fracturing. This study provides insights into the occurrence of tectonic earthquakes.

A Benchmarking Method to Rank the Performance of Physics-Based Earthquake Simulations

Abstract Physics-based earthquake simulators are an increasingly popular modeling tool in earthquake forecasting for seismic hazard as well as fault rupture behavior studies. Their popularity comes from their ability to overcome completeness limitations of real catalogs, and also because they allow reproducing complex fault rupture and interaction patterns via modeling the physical processes involved in earthquake nucleation and propagation. One important challenge of these models revolves around selecting the physical input parameters that will yield the better similarity to earthquake relationships observed in nature, for instance, the frictional parameters of the rate-and-state law—a and b—or the initial normal and shear stresses. Because of the scarcity of empirical data, such input parameters are often selected by trial–error exploration and predominantly manual model performance analyses, which can overall be time consuming. We present a new benchmarking approach to analyze and rank the relative performance of simultaneous earthquake simulation catalogs by quantitatively scoring their combined fit to three reference function types: (1) earthquake-scaling relationships, (2) the shape of the magnitude–frequency distributions, and (3) the rates of the surface ruptures from paleoseismology or paleoearthquake occurrences. The approach provides an effective and potentially more efficient approximation to easily identify the models and input parameter combinations that fit more closely to earthquake relations and behavior. The approach also facilitates the exhaustive analysis of many input parameter combinations, identifying systematic correlations between parameters and model outputs that can potentially improve the overall understanding of the physics-based models. Finally, we demonstrate how the method results agree with the published findings in other earthquake simulation evaluations, a fact that reinforces its overall usefulness. The model ranking outputs can be useful for subsequent analyses, particularly in seismic hazard applications, such as the selection of appropriate earthquake occurrence rate models and their weighting for a logic tree.

Experimental study on the rupture behaviors of orthogonal faults: effects of stress state and rupture initiation location

Summary Fault rupture dynamics is expected to be significantly affected by the geometry of fault system, especially for orthogonal faults. However, the rupture behaviors of orthogonal faults especially the coseismic interactions are far from fully understood. Here, we present experimental results from a series of laboratory earthquakes to elucidate the effect of the stress state and initiation location on the rupture behaviors of orthogonal faults. Our results reveal a phase diagram of rupture behaviors of orthogonal faults, which is collectively controlled by stress state and rupture initiation location. For events initiating from the main fault, the rupture cannot jump to the branch, which may be due to the clamping effect or the inhibited shear stress accumulation on the branch. On the contrary, events initiating from the branch can persistently trigger ruptures of the main fault. This difference highlights the directional effect associated with the rupture of orthogonal faults. Further, the rupture length of triggered ruptures on the main fault is controlled by the stress state of the fault system. With the increase of the ratio between the shear stress and normal stress, the rupture length of the main fault increases. Our results reproduce the rupture behaviors of orthogonal faults, which may provide insights into the rupture characteristics of natural earthquakes.

Creep rupture properties of dissimilar welded joint of ferritic/martensitic P92 steel and Inconel 617 alloy

The dissimilar welded joint (DWJ) comprising P92 steel and Inconel 617 (IN617) is frequently utilized in advanced ultra-supercritical (AUSC) boilers. In present work the creep rupture behaviour, rupture mechanism and microstructure evolution of DWJ of P92 steel and IN617 with Ni-based ERNiCrCoMo-1 filler, were examined at 650 °C under the stress range of 120–200 MPa. The results of the creep test indicated that the location of creep rupture varied across different testing conditions, encompassing areas such as P92 base metal and the fine-grained heat-affected zone (FGHAZ). The creep tested specimens within the stress range of 180–200 MPa exhibited failure originating from P92 base metal, predominantly influenced by plastic deformation. The failure manifested in a transgranular mode, driven by the formation, growth, and eventually coalescence of microvoids. The creep tested specimens within the stress range of 120–150 MPa displayed the characteristic ofType IV failure, primarily attributed to matrix softening and the absence of adequate precipitates to pin the PAGBs. Microstructural characterization unveiled the presence of microvoids along the PAGBs, facilitating microvoid nucleation primarily owing to the existence of the coarse brittle carbide phase. The growth of these microvoids over a period of time during tertiary stage of creep which lead to their coalescence and the formation of microcracks, ultimately resulting in premature intergranular failure. The specimen creep exposed at 650 °C under the lower stress of 120 MPa exhibited higher creep rupture life for 432 h. The SEM/EDS study of the crept sample of 120 MPa is also confirmed the presence of intermetallic laves phases in regions near the fracture tip and in the heat-affected zones (HAZs). Although the creep tested specimens at 150 MPa and 120 MPa exhibited failure in the FGHAZ and their elemental SEM/EDS analysis confirmed the presence of an oxide layer and notch formation near the interface of P92 base metal and ErNiCrCoMo-1 filler weld. The FESEM study revealed the growth of the oxide layer in the notch region, and it also showed the presence of multiple cracks and microvoids in the oxide layer. The formation and propagation of the oxide notch mainly led to the interfacial failure. The crept specimens subjected to 180 MPa and 200 MPa did not exhibit any cracks or microvoids in HAZs. However, specimens that failed under applied stresses of 120 MPa and 150 MPa revealed the presence of a high density of microvoids in the FGHAZ, inter-critical heat-affected zone (ICHAZ), and in the region of the coarse-grained heat-affected zone (CGHAZ) adjacent to the interface attached with an oxide layer.

Morphological differences across the Shumagin-Semidi fault segments control slip behaviors and tsunami genesis in the Aleutian-Alaska subduction zone

Rupture behaviors of a subduction megathrust define the slip type, the extent and the associated tsunami hazard. They are, however, difficult to be defined precisely due to limited fault-zone observations. Here, we integrate GNSS, tsunami-waveforms, seismic-profiles, and earthquake-cycle modeling to delineate the slip-extent of the 2020 Mw 7.8 Simeonof and the 2021 Mw 8.2 Chignik earthquakes in the Semidi segment; and to understand the possible structural and mechanical control on the distinct rupture behaviors of this segment and its neighboring Shumagin segment at the Aleutian-Alaska subduction zone. We show that both the Simeonof and Chignik earthquakes slipped a compact area at depth between ∼20 and 40 km that is well constrained by the combination of GNSS and tsunami-waveform data. We explain the distinct slip behaviors associated with the Semidi and Shumagin segments by highlighting the morphological changes in the fault along the strike direction. Beneath the Shumagin Island, we identify a structural-mechanical boundary that separates the megathrust into Semidi (east) and Shumagin (west) two segments. Semidi is gentle and curved; while Shumagin is steep and planar. The Semidi segment produces spatially-heterogenous stress field, and generates partial, full, complex ruptures as indicated in modeled cycles and in historical seismic observations. Meanwhile the Shumagin segment, coincides with the ocean-continent transition boundary – the Beringian margin, tend to generate slow-slip-events, tremors, otherwise, generates small or moderate seismicity as indicated in the modeled cycles and in seismic records since 1750. Our findings indicate that Semidi is likely to rupture in a chaotic fashion with major or large earthquakes, resulting a greater tsunami hazard like the 1938 Mw 8.2 event. The tsunami potential in the Unimak segment may also remain high.

Creep deformation behavior and residual life prediction of low hardness P91 steel welded joints

The remaining creep life of the reheat section pipeline of low hardness P91 steel replaced in a certain power plant was studied. The rupture behavior of the joint was studied using metallographic microscope (OM), scanning electron microscope (SEM), and Electron Back Scatter Diffraction (EBSD), and the creep life was predicted. The results show that the rupture behavior of P91 steel and its joint during service is related to external stress. When the stress is high, the failure position of the joint is concentrated at the lowest hardness position, dominated by low strength martensitic deformation cracking; When the stress is low, the joint fails from FGHAZ in the form of Type IV cracking, resulting in a combination of martensitic structure degradation and pore nucleation. Type IV cracking has a significant impact on the life of joints, and the polygonal line OSD method based on fracture mode for life prediction can effectively improve the accuracy of material life prediction.

Late Quaternary right-lateral slip rate along the Tangyuan segment of the Yilan–Yitong Fault Zone on the NE China Plain

The slip rate of strike-slip active faults is crucial for fault rupture behavior analysis and seismic hazard assessment. Although many segments of the Yilan–Yitong Fault Zone (YYFZ) in NE China have been strongly deformed since the late Quaternary, little progress has been made on its slip rate. With the help of high-resolution satellite images, detailed field investigations, seismic reflections, and Quaternary chronological dating, we mainly studied the late Quaternary right-slip rate of the YYFZ. Field investigations revealed an ∼15 km long by ∼1–2 m high-surface scarp belt extending along the Tangyuan graben interior, with a series of sag ponds and small parallel bulges. Research has revealed that the most recent paleoearthquake (∼M 7.0) occurred between 2,800± 600 a BP and 1,700 ± 200 a BP, with evidence of coseismic surface rupture. The T2 terrace abandonment age of the Heijin River is approximately 55.13 ± 1.78 ka (OSL), and the maximum cumulative right-lateral offset may reach 110 ± 5 m. Thus, the maximum right-slip rate of the Tangyuan segment of the YYFZ since the late Quaternary is constrained to 1–2 mm/a according to the upper terrace model. This study suggests that the presence of a new fault in the basin interior merits more attention when assessing the influential surface range and earthquake potential along the YYFZ, and the features of “low tectonic loading rate, activity migration in space, and clustering in time separated by ten thousand years of seismic quiescence” observed along the YYFZ are highly important for earthquake model construction and tectonic deformation studies in stable continental regions (SCRs).

Simulation of stress in a blood vessel due to plaque sediments in coronary artery disease

Atherosclerosis is a cardiovascular disease mainly caused by plaque deposition in blood vessels. Plaque comprises components such as thrombosis, fibrin, collagen, and lipid core. It plays an essential role in inducing rupture in a blood vessel. Generally, Plaque could be described as three kinds of elastic models: cellular Plaque, hypocellular Plaque, and calcified Plaque. The present study aimed to investigate the behavior of atherosclerotic plaque rupture according to different lipid cores using Fluid-Structure Interaction (FSI). The blood vessel was also varied with different thicknesses (0.05, 0.25, and 0.5 mm). In this study, FSI simulation with a cellular plaque model with various thicknesses was investigated to obtain information on plaque rupture. Results revealed that the blood vessel with Plaque having a lipid core represents higher stresses than those without a lipid core. Blood vessels’ thin thickness, like a thin cap, results in more considerable than Von Mises stress. The result also suggests that even at low fracture stress, the risk of rupture due to platelet decomposition at the gap was more significant for cellular plaques.

Study of rupture behavior of 40Cr ring-scored bursting diaphragms

The rupture diaphragm is a key part of pressure control in the launcher and the reliability of the rupture pressure is directly related to the internal ballistic performance. In order to study the rupture behavior of the 40Cr annular scored diaphragm under internal ballistic conditions and the remaining thickness of the diaphragm’s scoring, the stress-strain curve of the diaphragm is obtained by fitting the internal ballistic loading curve and simulation, the relationship between the rupture pressure and the remaining thickness of the scoring is established and the accuracy of the simulation is verified by the blasting test.

Numerical study on the rupture behavior of funicular liquid bridge between three spheres

Owing to the increase in saturation, unsaturated soil slopes are prone to experiencing landslides and mudflows during the rainy seasons. As liquid volume rises, the funicular regime between multiple particles gradually replaces the pendular regime within unsaturated granular soil. This study establishes a numerical model of a funicular liquid bridge between three spherical particles using the Surface Evolver software. The equilibrium state of the funicular bridge was examined using energy-minimization methods. The effects of liquid volume, contact angle, upper particle-pair gap, and separation distance on the capillary force and rupture distance were investigated. Finally, the relationship between capillary force and rupture distance is further elucidated based on meniscus profiles.

Plate interface geometry complexity and persistent heterogenous coupling revealed by a high-resolution earthquake focal mechanism catalog in Mentawai, Sumatra

Geometry and frictional states of the megathrust in subduction zones play critical roles on the rupture extent, hence the magnitude, of great earthquakes. However, their details are often difficult to obtain, primarily due to limited offshore geophysical observations. Here we overcome this challenge by precisely determining source parameters (i.e., location and focal mechanism) of medium-sized earthquakes using global broadband seismic waveform data. The dip angles of 108 Mw 5.0+ plate interface events from 1990 to 2017 in the central Sumatran subduction zone are tightly constrained by waveform inversion, and their locations are refined with surface-wave relocation and depth phases modeling. Our results reveal compact trench parallel earthquake belts at the up-dip and down-dip boundaries of the ruptures of the Mentawai 2007 Mw 8.4 and Mw 7.9 earthquakes. The down-dip seismicity belt marks ∼8º bending of the plate interface, suggesting that the change of fault geometry may have played a role in halting the megathrust rupture along with thermal effects. The up-dip seismicity belt shows a clear spatial complementarity to the largest events’ slip distribution. This belt is quite narrow (∼20 km) for the Mw 8.4 rupture but much broader (∼50 km) for the Mw 7.9 event. The combination of the up-dip seismicity belt and slip distributions matches well with the positive residual bathymetry and gravity anomalies, suggesting that these events resulted from long-term coupling on the plate boundary. Our findings suggest the importance of considering both up-dip and down-dip seismicity belts, along with residual bathymetry and gravity data, in understanding megathrust rupture behaviors and assessing the associated hazards.

Prediction of the Residual Resource of Pneumatic Tire Materials from Accumulation and Type of Damage

The present paper examines the mechanical characteristics at the boundary of the distribution of rubber matrix and metal and fabric fibrous materials as a distinct area in the crack braking mechanism, and their impact on the durability of pneumatic tires in the event of damage accumulation during operation. Experimental studies were conducted on the delamination of the components of the tire material composition in samples obtained from diverse locations of the car tire. The strength of the rubber matrix fibers of the metal cord was determined, which makes it possible to assess the overall strength of the tire material as a composition of reinforcing elements and the matrix during the accumulation of damage created artificially during operation. The method of experimental research is reasonably stable. The nature and behavior of the sample rupture during the tests were evaluated.