Contact Depth Research Articles

Characteristics of Open-Graded Friction Course Macrotexture and Macrostructure and Its Effect on Skid Resistance under Rainfall.

An Open-Graded Friction Course (OGFC) presents a rough surface and a porous structure and provides skid resistance under wet conditions, differing from that of a dense graded mixture. This study explored the distribution of surface macrotexture with depth in OGFC. Using cross-sectional images and semantic image segmentation techniques, the internal structure, porosity, and void size distribution were analyzed to assess the effectiveness of rainfall drainage. Skid resistance was evaluated with a British Pendulum Tester, focusing on the influence of surface macrotexture and internal macrostructure, particularly with regard to contact depth. Results show that finer gradations increase surface roughness peaks, which are concentrated near the top surface. In contrast, coarser mixtures exhibit a greater effective contact depth and more peaks with higher curvature. Finer gradations also result in lower porosity, greater void dispersion, and smaller average void diameters. During heavy rainfall, OGFC-13 exhibits the highest friction coefficient due to its effective contact, surface roughness, and internal voids, which facilitate water expulsion. This research provides insights into the skid resistance mechanism of OGFC in wet conditions and offers practical guidance for selecting the optimal gradation.

Mechanical Properties of Silicon Nitride in Different Morphologies: In Situ Experimental Analysis of Bulk and Whisker Structures.

Silicon nitride (Si3N4) is widely used in structural ceramics and advanced manufacturing due to its excellent mechanical properties and high-temperature stability. These applications always involve deformation under mechanical loads, necessitating a thorough understanding of their mechanical behavior and performance under load. However, the mechanical properties of Si3N4, particularly at the micro- and nanoscale, are not well understood. This study systematically investigated the mechanical properties of bulk Si3N4 and Si3N4 whiskers using in situ SEM indentation and uniaxial tensile strategies. First, nanoindentation tests on bulk Si3N4 at different contact depths ranging from 125 to 450 nm showed significant indentation size effect on modulus and hardness, presumably attributed to the strain gradient plasticity theory. Subsequently, in situ uniaxial tensile tests were performed on Si3N4 whiskers synthesized with two different sintering aids, MgSiN2 and Y2O3. The results indicated that whiskers sintered with Y2O3 exhibited higher modulus and strength compared to those sintered with MgSiN2. This work provides a deeper understanding of the mechanical behavior of Si3N4 at the micro- and nanoscale and offers guidance for the design of high-performance Si3N4 ceramic whiskers.

Structural modelling of subsurface geologic structures in Anambra and adjoining Bida Basins using aeromagnetic data: Implications for mineral explorations.

Aeromagnetic data over parts of the Northern Anambra and Southern Bida basins have been evaluated with emphasis on the subsurface geologic structures controlling mineralization and delineating the geomorphology of the basin. Four aeromagnetic data sheets (246 (Kabba), 247 (Lokoja), 266 (Auchi), and 267 (Idah)) were acquired through purchase, assemblage, analysis, and interpretation using integrated processing techniques of Euler deconvolution, analytical signal (AS), source parameter imaging (SPI), and 3D magnetic inversion model. The data are collected laterally in a series of NW-SE trajectories spaced 2 km apart, with an average flight altitude of approximately 150 m, and tielines occurring at approximately 20 km intervals. Qualitative observation of TMI and RAM shows that the research region is greatly fractured, with structures orienting in the E-W direction. The spectral analysis result shows that the sedimentary infillings range from 0.60 to 4.03 km. 3D model and curie isotherm depth subsurface maps reveal deeper curie depths at Kabba, Adavi, and Itakpe zones (28.0–40.0 km) and shallow curie depths at Auchi, Osara, Idah, and Anyigba areas (18.0–27.0 km). The result from the heat flow model shows an inverse relationship with the Curie isotherm depth. The contact depth sources calculated from Euler depth assessments show that the majority of these contact sources are trending in the E-W directions. The overall structural geomorphology of the research region conforms to the general pattern of structural trends within the research region. Most of the structures are trending NNE-SSW, NNW-SSE, and NE-SW, while the minor structures trend in the E-W direction. 3D inversion results show a discrete subsurface geologic structure that may house minerals within the region.

Contact analysis of output mechanism of cycloidal pinwheel reducer

In order to study the effect of design parameters on the contact performance of cycloid reducer, a new contact collision force model applicable to various restitution coefficients is proposed. Firstly, based on the L-N nonlinear contact theory and improved Winkler model, a contact force model with contact depth index and damping was proposed. Secondly, Hertzian contact theory was used to clarify the contact area, precise position and relative contact speed between the output pin and the cycloidal wheel in the presence of a clearance. By using the improved contact force model and simulation analysis, the effects of structural design parameters and working condition parameters on contact force were discussed. Finally, with the goal of reducing the contact force and volume of the reducer, the NSGA-II multi-objective genetic algorithm was used to construct an optimization model for the structural parameters of the reducer. The results show that the optimized structural parameters can effectively reduce the contact force of the output mechanism.

Virtual fit assessment of U.S. army body armor using NASA spacesuit techniques

Fit and accommodation are critical design goals for a body armor system to maximize Soldiers’ protection, comfort, mobility, and performance. The aim of this study is to assess fit and accommodation of body armor plates for the US Army. A virtual fit assessment technique, developed, validated, and deployed by NASA for spacesuit design, was adopted for this work. Specifically, 3D manikins of the Soldier population were overlaid virtually with geometrically similar surrogates of the armor plates. Trained subject matter experts with the US Army and NASA manually assessed the fit of the armor plates to manikins using a computer visualization tool and selected the appropriate plate size and position. A prediction model was built from the assessment data to predict the plate size from an arbitrary body shape and the resultant patterns of body-to-plate contact were quantified. The outcome indicated a unique trend of the plate sizes covarying with anthropometry. More pronouncedly, when the overlap between the body tissue and armor plate was quantified, female Soldiers are likely to experience a 25 times larger body-to-plate contact volume and 6.5 times larger contact depth than males on average, due to sex-based anthropometric differences. Overall, the prediction model and contact patterns provided key metrics for virtual body armor fit assessments, of which the locations, patterns, and magnitudes can help to improve sizing and fit of body armor systems, as previously demonstrated for NASA spacesuit design.

Nanoindentation Response of Structural Self-Healing Epoxy Resin: A Hybrid Experimental-Simulation Approach.

In recent years, self-healing polymers have emerged as a topic of considerable interest owing to their capability to partially restore material properties and thereby extend the product's lifespan. The main purpose of this study is to investigate the nanoindentation response in terms of hardness, reduced modulus, contact depth, and coefficient of friction of a self-healing resin developed for use in aeronautical and aerospace contexts. To achieve this, the bifunctional epoxy precursor underwent tailored functionalization to improve its toughness, facilitating effective compatibilization with a rubber phase dispersed within the host epoxy resin. This approach aimed to highlight the significant impact of the quantity and distribution of rubber domains within the resin on enhancing its mechanical properties. The main results are that pure resin (EP sample) exhibits a higher hardness (about 36.7% more) and reduced modulus (about 7% more), consequently leading to a lower contact depth and coefficient of friction (11.4% less) compared to other formulations that, conversely, are well-suited for preserving damage from mechanical stresses due to their capabilities in absorbing mechanical energy. Furthermore, finite element method (FEM) simulations of the nanoindentation process were conducted. The numerical results were meticulously compared with experimental data, demonstrating good agreement. The simulation study confirms that the EP sample with higher hardness and reduced modulus shows less penetration depth under the same applied load with respect to the other analyzed samples. Values of 877 nm (close to the experimental result of 876.1 nm) and 1010 nm (close to the experimental result of 1008.8 nm) were calculated for EP and the toughened self-healing sample (EP-R-160-T), respectively. The numerical results of the hardness provide a value of 0.42 GPa and 0.32 GPa for EP and EP-R-160-T, respectively, which match the experimental data of 0.41 GPa and 0.30 GPa. This validation of the FEM model underscores its efficacy in predicting the mechanical behavior of nanocomposite materials under nanoindentation. The proposed investigation aims to contribute knowledge and optimization tips about self-healing resins.

A Comparative Evaluation of Contact Angle and Depth of Penetration of Sodium Hypochlorite With Various Surfactants: An In Vitro Study.

Sodium hypochlorite (NaOCl) is regarded as the most frequently used root canal irrigant. Its high surface tension prevents its penetration into complex canal anatomies. The present study assesses the contact angle and penetration depth of 2.5% NaOCl with 0.2% cetrimide and propylene glycol. Sixty recently extractedmandibular premolars with a single root were obtained. Thirty were sectioned longitudinally, and the remaining 30 teeth were sectioned transversely. Acrylic blocks were used to mount the parts, and 5 µL of each of the following solutions was placed on the dentin surface: Group 1: 2.5% NaOCl (control), Group 2: 0.2% cetrimide + 2.5% NaOCl, and Group 3: propylene glycol + 2.5% NaOCl. Following this, contact angle analysis was made using a contact angle goniometer. We prepared and instrumented access cavities in 30 teeth to work up to the size of the ProTaper Gold F2 (Dentsply Tulsa Dental Specialties, Tulsa, OK). Samples were allocated to the three groups, and irrigation was done accordingly. They were sectioned at the coronal, middle, and apical thirds and then subjected to confocal laser scanning microscopy. The data were analyzed using a one-way ANOVA and a Tukey multiple comparison test. Group 2 had the least contact angle (35.20°) and the highest depth of penetration (DOP; 752.409 µm) when compared to Groups 1 and 3. The DOP decreased significantly from the coronal, middle, and apical thirds. No discernible variation in the contact angle was found between the radicular and coronal portions. 0.2% cetrimide improved the efficiency of 2.5% NaOCl as an irrigant by lowering its contact angle and increasing its DOP.

Investigating irradiation effects on metakaolin-based geopolymer

Nuclear power facilities face a critical challenge: concrete deterioration caused by prolonged neutron irradiation. This study explores a promising alternative, a metakaolin-based potassium geopolymer, which was implanted with Ti+ ions to mimic the irradiation. We observed significant improvements in the geopolymer's mechanical properties after irradiation. Nanoindentation showed that microhardness increased by a remarkable 90 %, accompanied by a 46 % rise in reduced modulus and a 23 % reduction in contact depth. However, irradiation also induced surface cracking. Detailed characterization revealed microstructural changes, including the disappearance of unreacted metakaolin and densification of the geopolymer matrix. While X-ray diffraction showed no significant structural alterations, Fourier-transform infrared spectroscopy indicated a decrease in water content, and Raman spectroscopy revealed a reduction in intensity, peak shift, and an increase in full-width half maximum, suggesting the presence of titanium ions and potential modifications in the local chemical environment. This initial investigation paves the way for geopolymers to be environmentally friendly alternatives in nuclear reactor shielding. While our findings highlight promising mechanical property improvements after irradiation, further development is necessary to address crack mitigation. This study provides new insights to guide future optimization of geopolymer composition and microstructure for enhanced resistance to irradiation effects.

Preparation method and industrialization of Ta-based ultra high temperature ceramic Tujia jar tea baking jar materials

The production materials of traditional Tujia jar tea often face problems such as poor high-temperature performance and poor durability. To improve the temperature resistance and durability of tea baking utensils, this study proposes a new type of TaC ultra-high temperature ceramic. TaC ceramics with excellent performance were prepared through powder metallurgy technology, including high-energy ball milling to ensure uniform mixing, followed by compression molding and high-temperature sintering. The test results demonstrated excellent mechanical properties, with a maximum depth of 948.67 nm and a contact depth of 954.45 nm, proving outstanding compressive and wear resistance. The hardness reached 21.4±0.5 Gpa, and the elastic modulus was 397.2±8.7 Gpa, both of which indicate its stability under high loads. In addition, the fracture toughness was 2.8±0.2 Mpa*m1/2. At a high temperature environment of 1000 °C, the oxidation rate constant of TaC ceramics was only 0.183 mg2 *cm−4 *h, which demonstrates its excellent high-temperature stability. The development of this TaC ceramic not only strengthened the traditional production process of Tujia teapots and tea roasting teapots, thereby improving the product’s service life, but also holds potential for other industrial applications that demand ultra-high temperature stability. These contributions provide new directions for the high-temperature application of ceramic materials and bring tangible economic and technological value to related industries.

An improved vision-based tactile skin with imaging adjustment system to reduce defocusing caused by contact depth changes

Imaging robustness of the vision-based tactile sensor (VTS) depends on coating wear resistance and imaging stability. With the miniaturization of sensors, the limited imaging space cannot afford a buffer against imaging deviations caused by contact depth changes. This paper proposes an improved vision-based thin tactile sensor (VTTS, also named vision-based tactile skin), integrating a focus-adjustable camera and an imaging adjustment system (IAS) to improve imaging robustness. The IAS contains an imaging calibration system and a focusing system. Since visuo-tactile sensing is performed in a relatively stable and closed imaging environment, the image-based focusing method is naturally matched with tactile imaging. Accordingly, an imaging calibration system based on a global search is designed to determine the focusing interval and shorten the focusing range. Three-point-fitting-based depth from focus (TPF-DFF) and deep-learning-based depth from defocus (DL-DFD) are proposed for low-frequency (simple)/high-frequency (complex) imaging adjustment. The experimental results demonstrate that the IAS-VTTS has close to 100% adjustment accuracy, and the fastest focusing time is up to 40 ms. Consequently, the IAS-VTTS can adapt to different deformation depths and support high-quality tactile imaging.

Molecular dynamics simulations into rolling scraping of nickel-copper bilayer film

In order to investigate the nanoscale friction mechanism and deformation behavior of nickel-copper bilayer film under rolling scraping, the effects of different factors during friction process such as the translation velocity, rotation velocity, radius of abrasive grain, contact depth, texture direction and crystallographic orientation are analyzed through molecular dynamics methods in terms of contact force, atomic lattice structure, internal substrate dislocation, kinetic energy and temperature. Results show that the contact force increases with the increase of the translation velocity or the decrease of the rotation velocity. Abrasive grains in a purely rolling state cause the most serious damage to the substrate. The contact force increases with the increase of contact depth or the decrease of abrasive grain radius. The crystallographic orientation has a significant effect on rolling scraping process and there is a crystallographic orientation with the minimum contact force. The degrees of substrate dislocation and the numbers of lattice reconstruction atoms under different factors and levels vary widely.

SORI: A softness-rendering interface to unravel the nature of softness perception

Tactile perception of softness serves a critical role in the survival, well-being, and social interaction among various species, including humans. This perception informs activities from food selection in animals to medical palpation for disease detection in humans. Despite its fundamental importance, a comprehensive understanding of how softness is neurologically and cognitively processed remains elusive. Previous research has demonstrated that the somatosensory system leverages both cutaneous and kinesthetic cues for the sensation of softness. Factors such as contact area, depth, and force play a particularly critical role in sensations experienced at the fingertips. Yet, existing haptic technologies designed to explore this phenomenon are limited, as they often couple force and contact area, failing to provide a real-world experience of softness perception. Our research introduces the softness-rendering interface (SORI), a haptic softness display designed to bridge this knowledge gap. Unlike its predecessors, SORI has the unique ability to decouple contact area and force, thereby allowing for a quantitative representation of softness sensations at the fingertips. Furthermore, SORI incorporates individual physical fingertip properties and model-based softness cue estimation and mapping to provide a highly personalized experience. Utilizing this method, SORI quantitatively replicates the sensation of softness on stationary, dynamic, homogeneous, and heterogeneous surfaces. We demonstrate that SORI accurately renders the surfaces of both virtual and daily objects, thereby presenting opportunities across a range of fields, from teleoperation to medical technology. Finally, our proposed method and SORI will expedite psychological and neuroscience research to unlock the nature of softness perception.

A rolling contact fatigue life prediction model for bearing steel considering its gradient structure due to cyclic hardening

This paper presents a rolling contact fatigue life prediction model for bearing steel. In the initial stage of rolling contact, the gradient structure appears in the subsurface region of bearing steel and the hardness shows a gradient distribution along the contact depth direction due to the roller compaction effect. This indicates that the fatigue resistance of bearing steel varies in the subsurface region. Besides, each subsurface material volume element is subject to different stress cycles. Based on Weibull theory, the survival possibility of subsurface volume elements is formulated. Then the rolling contact fatigue life is evaluated considering the stress state and anti-fatigue performance of each elementary volume of the subsurface material. According to the phenomenon and assumption, the model proposed for gradient material was applied in the rolling contact fatigue life prediction of the bearing steel GCr15 and validated with the fatigue experiment data in the open literature. Furthermore, the accuracy of the proposed model results was compared with the traditional empirical rolling contact fatigue life prediction models.

Cold-welded joint characteristics of gold nanowires via atomistic simulation

This study examines the effects of contact depth, contact orientation, contact angle, and nanowires temperature on the tensile strength of the gold nanowire generated via the cold welding process. There is an increase in the deformation rate with increasing contact depth. From 5 Å to 20 Å, the lattice matching of the nanowires is good, leading to a good weld joint. The greatest ultimate tensile strength (UTS) value is achieved at 5 Å contact depth compared to other depth cases. The UTS value is sensitive to the change in the contact orientation and the contact angle. Compared to other orientations, the (001) vs (001) orientation has the highest rate of orientation matching with the highest FCC structure ratio. Other orientations obtain a much lower UTS value. When the contact angle rises, the UTS value mainly decreases due to the higher level of lattice mismatch. Compared to the other angle cases, the maximum UTS value is attained at 0º contact angle. Moreover, changing in nanowires temperature within the 250 K450 K range do not result in significant variations in the sample's surface morphology, structural transformation, or atomic strain. At 250 K, the sample has the highest UTS value compared to other temperature cases.

Microstructure-Informed Prediction of Hardening in Ion-Irradiated Reactor Pressure Vessel Steels

Ion irradiation combined with nanoindentation is a promising tool for studying irradiation-induced hardening of nuclear materials, including reactor pressure vessel (RPV) steels. For RPV steels, the major sources of hardening are nm-sized irradiation-induced dislocation loops and solute atom clusters, both representing barriers for dislocation glide. The dispersed barrier hardening (DBH) model provides a link between the irradiation-induced nanofeatures and hardening. However, a number of details of the DBH model still require consideration. These include the role of the unirradiated microstructure, the proper treatment of the indentation size effect (ISE), and the appropriate superposition rule of individual hardening contributions. In the present study, two well-characterized RPV steels, each ion-irradiated up to two different levels of displacement damage, were investigated. Dislocation loops and solute atom clusters were characterized by transmission electron microscopy and atom probe tomography, respectively. Nanoindentation with a Berkovich indenter was used to measure indentation hardness as a function of the contact depth. In the present paper, the measured hardening profiles are compared with predictions based on different DBH models. Conclusions about the appropriate superposition rule and the consideration of the ISE (in terms of geometrically necessary dislocations) are drawn.

Correction of substrate-induced thin-film modulus deviations in nanoindentation measurements

The influence of substrate effects on the accurate measurement of mechanical properties of thin films remains to be clarified. Therefore, in this study, (AlCrNbSiTi)N thin films were deposited on four substrates—Si, SiO2, sapphire (Al2O3), and Ni—with varying thicknesses. Nanoindentation testing was conducted to measure the mechanical properties, revealing variations in the modulus of the thin film depending on the substrate and film thickness. To address these variations, we introduced the concept of two springs connected in series, following Hooke's law, to determine the elastic deformations of the thin film and its underlying substrate. By applying linear regression to four datasets corresponding to equivalent film thicknesses but different substrates, substrate-induced measurement errors were effectively mitigated, and the true modulus of the thin film was determined. Furthermore, we introduced a k value to represent the ratio of the actual force on the substrate to the force exerted by the indenter. Our findings indicate that even when the indenter contact depth is less than 1% of the film thickness, the substrate is still subjected to 7.6% of the applied force. This underscores the non-negligible nature of substrate elastic deformation during the measurement process and importance of correcting for substrate-induced variations in thin-film moduli. The findings can contribute to advancing the understanding of mechanical properties in ceramics and related materials.

Fault-seal analysis in the Greater Bay du Nord area, Flemish Pass Basin, offshore Newfoundland

A 3D subsurface structural model was built in a zone of the Greater Bay du Nord area, Flemish Pass Basin, offshore Newfoundland and Labrador, to carry out a post-drilled, fault-seal analysis in a multi-rift, geological complex setting; this aimed to test fault-seal predictions, calibrate computed static fault-zone attributes and estimate hydrocarbon contact depths. Hydrocarbon exploration campaigns in the Greater Bay du Nord area have primarily targeted rotated fault blocks that often exhibit structural segmentation and compartmentalization. A comprehensive approach that combines empirical and deterministic methods for static fault-seal analysis has been implemented. This approach provides insights into open, base and tight fault-seal scenarios, aiding prospect evaluation in this region. Notably, shale gouge ratios (SGRs) in the range 16–25% serve as a crucial indicator of the transition between fault-rock sealing and non-sealing fault segments. Furthermore, it emphasizes the critical role of hydrodynamics when calibrating or evaluating fault-sealing properties. In areas like the Greater Bay du Nord region, characterized by complex geology, it is imperative to regularly update fault-seal models. These updates should align with the availability of new subsurface data, comprehensive analyses and an improved understanding of the petroleum system. Thematic collection: This article is part of the Fault and top seals 2022 collection available at: https://www.lyellcollection.org/topic/collections/fault-and-top-seals-2022

Nanoindentation and scratching behaviors of diamond-like carbon films by coarse-grained molecular dynamics

High-performance coatings such as diamond-like carbon (DLC) films own thin thickness which is in the gap of experiment and molecular dynamics (MD), limiting the measurement of their intrinsic mechanical properties. To achieve the direct comparison between experiment and simulation, modified parameters of Tersoff potential describing the interaction among amorphous carbon accurately are proposed for coarse-grained MD simulations of DLC films. Such parameters are validated in compression and shear loadings compared with all-atom MD. A fitted mathematical contact model of the actual contact depth of indenter in nanoindentation is studied. By using this model, the elastic moduli of DLC films have been computed and the effect of relaxation is discussed. Besides magnified dimensions, the larger mass of coarse-grained beads enables the greater time interval, realizing the friction simulation of DLC films at experimental sliding velocities, and giving a methodological inspiration for the studies of mesoscopic simulations of amorphous materials.

Mechanical and Surface Characteristics of Selective Laser Melting-Manufactured Dental Prostheses in Different Processing Stages.

Due to the expansion of the use of powder bed fusion metal additive technologies in the medical field, especially for the realization of dental prostheses, in this paper, the authors propose a comparative experimental study of the mechanical characteristics and the state of their microscale surfaces. The comparison was made from material considerations starting from two dental alloys commonly used to realize dental prostheses: Ni-Cr and Co-Cr, but also technologies for obtaining selective laser melting (SLM) and conventional casting. In addition, to compare the performances with the classical casting technology, for the dental prostheses obtained through SLM, the post-processing stage in which they are in a preliminary finishing and polished state was considered. Therefore, for the determination of important mechanical characteristics and the comparative study of dental prostheses, the indentation test was used, after which the hardness, penetration depths (maximum, permanent, and contact depth), contact stiffness, and contact surface were established, and for the determination of the microtopography of the surfaces, atomic force microscopy (AFM) was used, obtaining the local areal roughness parameters at the miniaturized scale-surface average roughness, root-mean-square roughness (RMS), and peak-to-peak values. Following the research carried out, several interesting conclusions were drawn, and the superiority of the SLM technology over the classic casting method for the production of dental prostheses in terms of some mechanical properties was highlighted. At the same time, the degree of finishing of dental prostheses made by SLM has a significant impact on the mechanical characteristics and especially the local roughness parameters on a miniaturized scale, and if we consider the same degree of finishing, no major differences are observed in the roughness parameters of the surfaces of the prostheses produced by different technologies.

How displacement analysis may aid fault risking strategies for CO2 storage

AbstractDeveloping an accurate understanding of the ways in which faults have grown within a particular region and stratigraphy can aid risk management for CO2 storage sites. Areas of fault interaction lead to differences in the stress field, resulting in an increased strain, which is often accommodated by a high intensity of deformation bands and/or fracturing, dependent on host rock properties. These structures alter the permeability surrounding faults. Hence, detecting areas of interaction of structures throughout the fault growth history allows the identification of locations where high risk may occur in terms of the hydraulic properties of a fault zone. The Vette Fault Zone (VFZ), bounding the Alpha prospect within the potential CO2 Smeaheia storage site, Northern Horda Platform, is shown to have grown from a minimum of seven fault segments. By utilising a comparison with the adjacent Tusse Fault Zone (TFZ), we can identify potential areas of high risk, where fluids may have the ability to flow across or along the VFZ. The high seal strength of the TFZ holding back a large gas column is likely to be created by shale juxtaposition and smearing with cataclastic processes. The same could be assumed for the VFZ, associated with similar tectonics and displaced stratigraphy. However, rather than membrane breaching causing fluids to flow across the fault, potential areas of high risk have been identified at locations of relict breached relay zones, where the initial displacement of the intersecting faults and area of overlap was high. These areas appear to correspond with the location of hydrocarbon contact depth (spill point) along the TFZ. Using the same assumptions for the VFZ, we can observe one potential area of high risk, which lies within the area of suggested CO2 accumulation.