Debonding Process Research Articles

Grammar of Giants


 
 
 It is a common process of language change for free morphemes to become bound morphemes, but the inverse process (termed ‘debonding’ by Norde 2009) is much rarer. Previous studies have found that lexemes with the original meaning ‘giant’ (German Riesen, Dutch reuze) have historically grammaticalized as prefixes, and subsequently debonded into free morphemes with the same bleached meaning as the prefixes (Van Goethem & Hiligsmann 2014; Norde & Van Goethem 2014). Using a synchronic corpus of written Danish (KorpusDK), this paper shows that the Danish word kæmpe, originally ‘giant’, is in the late stages of a similar process of debonding. By investigating the morphological and syntactic patterning of kæmpe, the paper shows that kæmpe has indeed debonded, and occurs as a free-standing semantically bleached adjective, but that it does not yet exhibit fully prototypical adjectival behavior. All three functions of kæmpe remain in use: a noun with the specific meaning ‘giant’, a semantically bleached prefix, and a corresponding semantically bleached adjective. This would argue against an account relying on abrupt category change, and it is proposed that kæmpe has reached its current status through gradual analogy-driven change.
 
 

Laser Debonding of Ultrathin Wafers and Packages: A Technology for the New Generation of Electronic Devices

The continuous shrinkage of the device wafers thickness is driving the current mature debonding technologies to their limits. The challenging form factor demands for memory (≤ 30 µm) or new generations of power devices applications are just two examples for the need of lowering the device thickness.Slide-off as well as mechanical debonding are methods currently in use in high volume production, but these two technologies are not capable to support the new requirements in terms of thermal and mechanical stability, handling, throughput (affecting the cost of ownership - CoO), and process margin. Therefore, device manufactures are looking for a more versatile, universal debonding technology. State of the art UV laser debonding is a very promising candidate which can help bringing the required process margin and flexibility. By combining laser debonding and thermoset materials with a high thermal budget the process window can be significantly enhanced.Most of the thermoset materials of interest which are used to form a bond and to embed the device topography cannot be stimulated directly with UV light. In order to enable a debonding process for these materials, an additional layer is commonly deposited on the carrier. The post bond uniformity (quantified typically by the total thickness variation - TTV) of the used bulk layer of thermoset adhesive has to be very well controlled in order to enable a defect free thinning of the device wafer: this becomes crucial particularly when the final device layer has to be thinned down below 10 µm. Besides the optimization of the bond layer thickness uniformity, suitable carriers for different devices and applications were evaluated. Due to the significant variety of the available glass carriers, a customized temporary bonding process can be developed by selecting the most appropriate adhesive and carrier combinations suitable even for very challenging substrates, like reconstituted wafers.Reconstituted wafers consist of a number of different layers and materials with different thermal expansion coefficients, which makes the stress management and the handling of such substrates extremely difficult. However, the choice of the suitable carrier enables the processing independent of the chosen integration process flow (RDL first; Chip first). Even a carrier flip flop to enable the processing of the back side of the very thin package is possible and this is enabling the creation of ultra-thin and smart packages.The scope of the current work was to address the post bond adhesive thickness uniformity as well as the stress management. Experimental results will be presented for the process optimization: figure 1 shows two bow measurement results for two different carrier materials and figure 2 shows an example of post-bonding thermoset adhesive uniformity measurement Figure 1

Effect of an Er,Cr:YSGG Laser on the Debonding of Lithium Disilicate Veneers With Four Different Thicknesses.

Introduction: The objective of this study was to compare in vitro the resistance and type of failure in the debonding of lithium disilicate veneers with four different thicknesses using an erbium chromium yttrium-scandium gallium-garnet (Er,Cr:YSGG) laser. Methods: Sixty-eight bovine teeth were used to bond round lithium disilicate veneers with a 6-millimeter diameter and four different thicknesses: group 1 (0.4 mm), group 2 (0.8 mm), group 3 (1.2 mm) and group 4 (1.6 mm). Each sample was irradiated with an Er,Cr:YSGG laser with 4 W of power and a frequency of 50 Hz, during 60 seconds, scanning concentrically. The energy density per pulse or fluency applied was 5.33 J/cm2 for the four groups. The samples were subjected to a force in a universal testing machine and then observed under a microscope to determine the type of failure. Data were statistically analyzed with the non-parametric Kruskal-Wallis test. Results: The tendency in the results revealed that the thicker veneers showed more resistance to the debonding process. The debonding strength for group 3 was the highest (5.62 MPa), followed by group 4 (5.20 MPa), then group 2 (0.85 MPa) and finally group 1 (0.0 MPa). The most frequent type of failure was cohesive failure in cement (CC) for all groups, with 73.53% (P ≤ 0.083). Conclusion: Er,Cr:YSGG laser irradiation influences the debonding of lithium disilicate veneers with different thicknesses: the smaller thickness showed the greater debonding. The thickness of veneers was not associated with the type of failure.

An MD study of the polymer–polymer adhesion via connector chains: some aspects of the competition between bulk dissipation in the interphase and pull-out of interface-connecting molecules

Atomistic simulation approach was used to analyze the separation behavior of polymer–polymer interfaces. This was achieved using coarse-grained molecular dynamics (MD) simulations of some connector chains embedded in two adjacent polymer entangled melts. To separate the contribution of polymer molecules pull-out from the micro-bulk dissipation in the viscoplastic interphase, surrounding the surface of separation, two kinds of simulations were considered: (a), simulations of the pull-out mechanism, where the extraction of the connectors out of the melts takes place through a complex mechanism of forced reptation only; (b), simulations of the full debonding process where the micro-bulk dissipation contributes to the overall crack opening and can skew the description of the interface separation by pure connector molecules pull-out. From the MD simulation results, some relevant parameters (e.g., a cohesive strength or an adhesion energy) of the separation behavior of the interface being modelized were extracted. In addition, one was able to separate quantitatively connector pull-out from micro-bulk dissipation (in the surrounding bulk region of the interface). This means that we were able to emphasize: (i) how the straining divides into interface opening and bulk deformation and (ii), how the macroscopic opening rate diffuses throughout the melts and the interface opening rate, since the mechanical behavior of polymers is strain-rate dependent. A comparison between two kinds of MD simulations, where a system is stretched along one direction, is shortly discussed as a necessary prelude to future investigations.

Interface bond between FRP systems and substrate: Analytical modeling

In the field of external strengthening and repairing of existing reinforced concrete structures, steel reinforced polymers (SRP) systems have emerged as a competitive alternative to the use of the more common carbon and glass fiber reinforced polymer (FRP) composites. Experimental investigations have frequently shown the potentials of these innovative composite systems in improving the performance of deficient structural members. At the same time, additional studies are needed to expand the existing knowledge and either to provide design recommendations or to develop specific guidelines. The paper fills some of the foregoing knowledge gaps by presenting an analytical investigation on the bond behaviour between SRP and concrete in which closed-form solutions are derived to predict the entire debonding propagation process. In particular, accurate and simplified local shear stress-slip (τ-s) laws are employed in the proposed modelling from which different expressions for the interfacial shear stress distribution, the axial stress profile and the concrete-SRP relative displacement (slip) are developed and commented in the paper; analytical estimates of the SRP effective bonded length are provided as well as relationships for calculating the maximum axial stress (or peak force) at SRP laminate debonding.The analytical procedure was, firstly, applied to simulate some single-lap shear tests performed in a previous experimental program with the purpose to investigate the influence on the debonding propagation process of the following main parameters: a) concrete strength, b) concrete surface finish and c) steel tape density. Then, the comparisons between the numerical simulations and the experimental results available for some bond tests have allowed for verifying the accuracy of the proposed modelling.

Closed-form solutions for modellingthe response of adhesively bonded joints under thermal loading through exponential softening laws

The bonding technique has received extensive attention in the recent decades. Unlike the use of metallic screws, screws or rivets, some of the advantages of this bonding technique include the elimination of stress concentration, lighter weight and the extension of the life cycle of the adhesively bonded structures. The stiffness and strength of a material are increased after bonding with another reinforced material, but it can only be effective if the interface is able to transfer bond stresses. However, how the bond stress transfer is carried out when the joint, reinforcement and substrate are subjected to a thermal loading is not yet well understood. One way to facilitate and improve such knowledge is to develop analytical solutions that, despite their simplicity, allow parameters to be identified that may directly influence the bond between materials. Therefore, the present study aims to develop a series of closed-form solutions able to describe the debonding process of bonded joints with different characteristics using two different exponential softening laws. The results mainly describe the interfacial slips, bond stresses and strains in both materials during the temperature increase process. In total, 108 examples with different bonding conditions are studied and, at the same time, numerically modelled through the Finite Element Method (FEM). The numerical results were compared to the proposed closed-form solutions and a satisfactory agreement was obtained between the numerical and analytical results, validating the latter. When considered in the simulations, the glass transition temperature (Tg) of the adhesive greatly affected the bond stress transfer between materials and compromising the initial integrity of the adhesively bonded structure.

Hydrophilic direct bonding and debonding of ultrathin glass substrates for high-temperature devices

The direct hydrophilic bonding and debonding of ultrathin glass substrates onto and off from a glass carrier has been investigated, and a methodology is presented to reduce the excessive bonding strength after high-temperature annealing to facilitate the debonding process. It is found that with a preliminary surface conditioning of glasses at 300 °C and 400 °C in vacuum at 1 mbar before bonding, the specific surface energy of bonded wafers after high-temperature annealing for 30 min reduces to about 72% and 50% as compared to the control samples that have been surface-conditioned at room temperature instead.

Modeling the Interfacial Debonding Behavior Between Steel Wire and Adhesive

Abstract A polyethylene pipe reinforced by winding steel wires (PSP) has been widely used in the petroleum, chemical, and water supply industries. The PSP has outstanding mechanical properties due to its unique composite structure. However, interfacial debonding between steel wire and adhesive sometimes occurs when the temperature and inner pressure increases to some extent in the application. In this study, the interfacial behavior between steel wire and adhesive was investigated and the interfacial failure process was analyzed. First, to acquire test data of interfacial failure, pull-out tests were conducted using specimens consisted of steel wire and adhesive. Specimens were prepared per the PSP manufacturing process, and a temperature change occurred in the specimens' preparation. Second, as the details of failure process could not be observed directly, finite element models were established to represent the mechanical behavior of the steel-polymer interface in-order to reproduce the debonding failure process. The thermal preload was taken into account in the model, and its influence on interfacial behavior was discussed. Contact surface with cohesive behavior was utilized to characterize the interfacial property. Finally, the interfacial failure process including stick–slip interaction and frictional sliding interaction was modeled in the simulation. The simulation result agreed well with the experimental data. Based on the finite element model, the cause and the distribution of thermal residual stress in pull-out specimen were illuminated. Further, it is discussed that how the stress distribution changes along the adhesive interface.

Investigation on meso-debonding process of the sandstone–concrete interface induced by freeze–thaw cycles using NMR technology

Abstract Sufficient bonding at concrete–rock interfaces is an important prerequisite when designing supports using concrete or shotcrete. However, the bonding between concrete and rock is often affected by low temperatures in cold regions. This study focuses on the effects that freeze–thaw cycles have on meso-debonding at sandstone–concrete interfaces. The prepared sandstone-concretes composite materials were subjected to freeze–thaw cycles and nuclear magnetic resonance (NMR) test. The effects of the freeze–thaw cycles on sandstone–concrete composites and the interfacial pore changes are discussed in this paper. The extent of the interface-influencing zone (IIZ) and the process controlling interface debonding are described based on the results of those experiments. The three primary conclusions are as follows: (1) The volume of the micropores and macropores in sandstone increases with the freeze–thaw cycles; however, the volume of the mesopores decreases. (2) The IIZ lies in the sandstone, near the interface, and is accompanied by water enrichment. (3) From a mesoscopic point of view, the process of debonding in the sandstone-concrete is not initialized at the interface but occurs in the sandstone near the interface.

Safety performance monitoring of smart FBG-based FRP anchors

Fibre Reinforced Polymer (FRP) bar is a versatile element applied to the civil engineering industry. Considering its low shear strength, the anchoring performance is of concern. For FRP anchoring system, the safety monitoring is a new approach to investigate the performance in anchoring and long-term safety use. Based on the material properties and the requirements of anchorage and safety monitoring, this paper proposes an innovative smart Fibre Bragg Grating (FBG)-based FRP anchor by introducing FBG into FPR bonding anchor. The debonding damage process and the failure sensitivity of the smart anchor were investigated during the pull-out tests. Additionally, the strain distribution inside the anchor under pull out load and the law of strain varying with load were analysed. Based on the experimental results, the theoretical analysis and numerical simulation of the smart anchor were carried out. Further, the debonding damage mechanism and failure mode, the distribution model and simplified calculation model of the interfacial shear stress between FRP bar and epoxy were put forward. Moreover, the FRP bonding anchor theory, the safety monitoring and failure evaluation method of FBG-based FRP anchor were developed.

Numerical simulation investigation on fracture debonding failure of cement plug/casing interface in abandoned wells

The fracture debonding failure of cement plug/casing interface caused by the migration of underground fluid with pressure accumulation imposed serious challenges to wellbore integrity of abandoned wells. This paper presents an investigation with a view of quantifying the relationships between the fracture debonding height and the migration time of underground fluid. A new 3D numerical model of cement plug/casing/cement sheath/formation system based on the cohesive zone method, which was validated by microannulus experiment, was developed to simulate the fracture debonding process. And then the relationships between fracture debonding height and propagation pressure was studied. Additionally, the influence of horizontal in-situ stress, cement plug mechanical parameters, and interface properties on the fracture debonding height and development geometry were also analyzed. The results of research indicated that the minimum horizontal in-situ stress played a decisive role in controlling the fracture propagation of cement/casing interface. Debonding fracture propagated along the whole circumference of the interface with the same height for the case that the horizontal in-situ stress was uniform, while propagated along a certain circumference angle of the interface with the maximum height in the direction of maximum horizontal principal stress for the case that the horizontal in-situ stress was non-uniform. The results of numerical analysis showed that lower elastic modulus and Poisson's ratio of cement plug, higher cement plug permeability, and larger critical normal strength and critical shear strength were beneficial to decrease the fracture debonding height and reduce the risk of debonding failure of the cement plug/casing interface. Finally, some effective measures to maintain the sealing integrity of abandoned wells were proposed.

Identification of interfacial properties of FRP plated beams using debonding dynamics

This paper faces the challenge of identifying the interfacial cohesive properties used for the debonding analysis of beams strengthened with composite materials. Motivated by the unstable and dynamic nature of the debonding mechanism, the procedure developed in this work uses experimental measurements of the dynamic aspects of the process. This approach is based on the hypothesis that the dynamic aspects carry information regarding the structural system at hand. To face this challenge, a parameter identification procedure that aims at the assessment of the work of separation and the characteristic length scale of the interface is developed. The procedure uses dynamic experimental results taken form the literature, a high order analytical approach for the modeling of the layered structure, and its finite element counterpart. The capabilities of the approach are explored through the examination of two cases: one used for the parameter identification and the other used for testing the analysis with the determined parameters. Finally, various combinations of weights that shift the focus from static observations to dynamic ones are examined. The findings imply that the kinematics of the debonding process reflect on the tacit information on the structural system and contribute to the effort of its assessment.

Effect of temperature variations on interfacial debonding of FRP-plated beams: A coupled mix-mode cohesive zone modeling

The use of fiber-reinforced polymer (FRP) plates for the strengthening of structural members involves their exposure to service temperature variations (i.e., thermal loadings). Such temperature variations may lead to thermal stress and the interfacial debonding of the FRP-plated beam as a result of the thermal mismatch between the FRP plate and the substrate beam. There is lacking research related to the effect of temperature variations on the interfacial debonding of FRP-plated beams. This paper presents the first-ever analytical study on the behavior of the FRP-plated beam under combined thermal and mechanical loadings. The interfacial stress and slip evolutions as well as the debonding process of the FRP-plated beam are estimated based on a coupled mix-mode cohesive zone modeling. In addition, a finite element (FE) approach is proposed to verify the analytical solution in which the analytical results are compared with the FE model predictions, indicating that a good agreement was achieved between the analytical and FE results.

Interfacial debonding detection in externally bonded bfrp reinforced concrete using stress wave-based sensing approach

Fibre-reinforced polymer (FRP) composite materials have been increasingly used for strengthening concrete members. The strengthening performance and structural capacity of FRP reinforced concrete (RC) structures are highly influenced by the interfacial bonding behaviour between FRP and concrete. A reliable technique for debonding detection, especially at its early age, is essential to ensure the strengthening efficacy and avoid premature failure of FRP RC structures. This study develops a stress wave-based sensing approach to quantitatively monitor the debonding process by using surface mounted piezoceramic-based transducers (also called as smart aggregates SAs). The scanning wave signals in swept frequency mode and single frequency mode were utilised in experimental and numerical methods, respectively. Both results showed that when the stress wave propagated through the FRP-concrete interface, the wave energy attenuation increased as the debonding developed. To quantify the debonding level and provide assessment of the interface condition, a wavelet packet-based debonding index was established and its validity was verified by the data retrieved from digital image correlation measurement. The proposed method has potential for fast determination or real-time monitoring of FRP-concrete interfacial debonding for both research and field applications.

Strengthening RC beams using externally bonded CFRP sheets with end self-locking

When laminates of fiber reinforced polymer (FRP) are just bonded on the substrate of reinforced concrete (RC) members for strengthening, debonding failure often happens prematurely and suddenly on the FRP-concrete joints. It is unbeneficial to efficient employment of FRP and reliable service of the structures. This paper introduces a mixed anchoring technique for FRP sheets that combines external bonding (EB) and a novel type of end anchorage. FRP sheets are self-locked at ends by wrapping about a slotted plate in a specified way. Experiments on four concrete beams demonstrated that adding end self-locking to EB can effectively solve the serious problems of usual debonding. End debonding was simply prohibited and intermediate crack debonding was substantially restricted despite occurrence. As a result, not only ultimate strength but also failure ductility of the strengthened specimens was greatly enhanced. The final failure featured by either FRP rupture or concrete crush regardless of debonding degree. Finite element models are then established to simulate the responses of the strengthened beams with hybrid anchored FRP. The numerical results show good agreements with the test observations including debonding process and failure modes. It proves capability and accuracy of the modeling as a useful tool for further research.

Effect of Mesh Sensitivity and Cohesive Properties on Simulation of Typha Fiber/Epoxy Microbond Test

The microbond test for natural fibers is difficult to conduct experimentally due to several challenges including controlling the gap distance of the blade, the meniscus shape, and the large data spread. In this study, a finite element simulation was performed to investigate the effects of the bonding characteristics in the interface between the fiber and matrix on the Typha fiber/epoxy microbond test. Our aim was to obtain the accurate mesh and cohesive properties via simulation of the Typha fiber/epoxy microbond test using the cohesive zone model technique. The axisymmetric model was generated to model the microbond test specimen with a cohesive layer between the fiber and matrix. The cohesive parameter and mesh type were varied to determine the appropriate cohesive properties and mesh type. The fine mesh with 61,016 elements and cohesive properties including stiffness coefficients Knn = 2700 N/mm3, Ktt = 2700 N/mm3, and Kss = 2700 N/mm3; fracture energy of 15.15 N/mm; and damage initiation tnn = 270 N/mm2, ttt = 270 N/mm2, and tss = 270 N/mm2 were the most suitable. The cohesive zone model can describe the debonding process in the simulation of the Typha fiber/epoxy microbond test. Therefore, the results of the Typha fiber/epoxy microbond simulation can be used in the simulation of Typha fiber reinforced composites at the macro-scale.

The effect of different mouthwashes on bacteremia after debonding.

This study aims to investigate the effects of various mouthwashes on bacteremia development following a debonding process, which is performed after orthodontic treatment. The study included patients who received fixed orthodontic treatment and were indicated for debonding. A total of 40 patients in four groups were selected for the study; no mouthwash (Group 1), mouthwash containing 0.12% chlorhexidine-gluconate (Group 2), mouthwash containing essential-oils (Group 3), and mouthwash containing 7.5% povidone-iodine (Group 4). Before (T0) and following (T1) the debonding procedure, blood samples were obtained from the patients. Then, the blood samples were placed in blood culture bottles to investigate bacterial growth. Based on the results of the study, it was determined that the blood samples obtained at T0did not indicate any bacterial growth. Furthermore, it was observed that the blood samples obtained at T1included Streptococcus viridans, Streptococcus oralis, Streptococcus mutans, and Staphylococcus aereus growth, respectively, in 4 patients from Group 1 while Streptococcus salivarius growth was observed in 1 patient from Group 3 in addition to Streptococcus mitis growth in 1 patient from Group 4. No bacterial growth was observed in Group 2. While the results obtained between Group 1 and Group 2 were statistically significant, no statistically significant difference was observed between other groups. Finally, it was determined that the mouthwash 0.12% chlorhexidine-gluconate was statistically significant in comparison to the control group. It can be concluded that this mouthwash can be used to decrease bacterial density in oral flora before debonding procedures.

Numerical simulation of the debonding process in pull-out tests of near-surface mounted FRP rod in concrete

Purpose Near-surface mounted (NSM) fiber-reinforced polymer (FRP) rod is extensively applied in reinforced concrete (RC) structures. The mechanical performances of NSM FRP-strengthened RC structures depend on the bond behavior between NSM reinforcement and concrete. This behavior is typically studied by performing pull-out tests; however, the failure behavior, which is crucial to the local debonding process, is not yet sufficiently understood. Design/methodology/approach In this study, a three-dimensional meso-scale finite element method considering the cohesion and adhesion failures is presented to model the debonding failure process in pull-out tests of NSM FRP rod in concrete. The smeared crack model is used to capture the cohesion failures in the adhesive or concrete. The interfacial constitutive model is applied to simulate the adhesion failures on the FRP-adhesive and concrete-adhesive contact interfaces. Findings The present method is first validated by two simple examples and then applied to a practical NSM FRP system. This work studied in detail the debonding process, the bond failure types, the location of peak bond stress, the transmitting deformation in adhesive and the morphology of contact zone. The developed method provides a practical and convenient tool applicable for further investigations on the debonding mechanism for the NSM FRP rod in concrete. Originality/value A three-dimensional meso-scale finite element method considering the cohesion and adhesion failures is presented to model the debonding failure in NSM FRP-strengthened RC structures. The smeared crack model and the interfacial constitutive model are introduced to develop a convenient approach to analyze the failures in adhesive, concrete and related interfaces. The developed numerical method is applicable for studying the debonding process, the bond failure types, the location of peak bond stress, the transmitting deformation in adhesive and the morphology of contact zone in detail.

Experimental and numerical investigation of debonding process of the FRP plate-concrete interface

Single shear tests performed to study the debonding between the concrete and the FRP plate of 2 mm thickness are presented. Specimens with five different bond lengths have been tested. In order to investigate the debonding mechanism and measure the complete strain distribution, digital image correlation (DIC) method was applied. The shear stress and slip distribution curves were calculated from the strain distribution functions fitted from measured strain data. Based on the features of the shear stress transfer zone under different load levels, the whole loading process has been divided into four stages: (1) elastic stage; (2) cracking stage; (3) debonding stage; (4) failure stage. According to the relationship between the relative bearing capacity and bond length, a concept of efficient bond length was suggested. A bi-linear bond stress-slip model was calibrated by the constitutive parameters of the experimental shear stress-slip curves. Based on the bi-linear bond stress-slip relationship, a numerical model of FRP plate-concrete interface was built using the bonded-particle model (BPM) and the debonding process was numerically analyzed. The numerical results present good agreement with the experimental results in the load-slip response and the shear stress distribution along the bond length. The comparison between the experimental and the numerical results shows that BPM can effectively simulate the debonding process of the FRP plate-concrete interface.

Analysis of instability mechanisms of natural fractures during the approach of a hydraulic fracture

A fluid-driven fracture propagation model dominated by viscosity-leak-off regime was presented to investigate the mechanical stability of natural fracture (NF) when hydraulic fracture (HF) approaches. The induced stresses generated by the approaching HF were calculated by a fully coupled integro-differential equation. The pore pressure effect caused by fracturing fluid leak-off was simulated based on dual porosity medium theory. The critical failure conditions of NF were determined based on maximum tensile criterion and Barton-Bandis criterion. The sensitivity of the stability of NF to in-situ stress anisotropy, approaching angle and distance, injection rate, fracturing fluid viscosity, and NF properties was analyzed in detail. Simulation results reveal that the shearing-mode failure of NF is obviously easier than the opening-mode failure, and the shear slip zone is much larger than the tensile failure zone. As HF approaches NF non-orthogonally, the induced debonding process is unstable, and the debonding zone is asymmetric with respect to the center of NF. The tensile-induced expansion zone is primarily located in the portion of NF ahead of the HF tip, however the shear-induced slip zone can even occur on NF behind of the HF tip. Induced stresses alone have negligible effect on the stability of the NF that is unconnected to the HF. The change in pore pressure due to leak-off effect dominates the final stimulated reservoir volume during large-scale fracturing. The instability of the NF dominates the propagation trajectory of the subsequent HF. A more suitable arrested/crossing condition by extending Gu-Weng criterion was established to predict the path of HF propagation.