The transient and static anti-plane problem of a rigid line inclusion pulled out from an elastic medium is studied.The singular integral equation method is used to solve the stress field.Under the static load,the stre...The transient and static anti-plane problem of a rigid line inclusion pulled out from an elastic medium is studied.The singular integral equation method is used to solve the stress field.Under the static load,the stress intensity factor(SIF)at the inclusion tips increases with the medium length.The problem becomes equivalent to an inclusion in a medium with an infinite length when the length of the medium is 3.5times longer than that of the inclusion.However,under the transient load,the maximum value of the SIF occurs when the medium length is about two times the inclusion length.Besides,the relation between the pull-out force and the anti-plane displacement is given.The conclusions are useful in guiding the design of fiber reinforced composite materials.展开更多
Laboratory pull-out tests were conducted on the following rock bolts and cable bolts:steel rebars,smooth steel bars,fiberglass reinforced polymer threaded bolts,flexible cable bolts,IR5/IN special cable bolts and Mini...Laboratory pull-out tests were conducted on the following rock bolts and cable bolts:steel rebars,smooth steel bars,fiberglass reinforced polymer threaded bolts,flexible cable bolts,IR5/IN special cable bolts and Mini-cage cable bolts.The diameter of the tested bolts was between 16 mm and 26 mm.The bolts were grouted in a sandstone sample using resin or cement grouts.The tests were conducted under either constant radial stiffness or constant confining pressure boundary conditions applied on the outer surface of the rock sample.In most tests,the rate of displacement was about 0.02 mm/s.The tests were performed using a pull-out bench that allows testing a wide range of parameters.This paper provides an extensive database of laboratory pull-out test results and confirms the influence of the confining pressure and the embedment length on the pull-out response(rock bolts and cable bolts).It also highlights the sensitivity of the results to the operating conditions and to the behavior of the sample as a whole,which cannot be neglected when the test results are used to assess the bolt-grout or the grouterock interface.展开更多
Experimental investigation on the pull-out behaviour,including the withdrawal capacity,slip stiffness and inter-facial shear stress,of axially loaded screwed-in threaded rod embedded in cross laminated timber(CLT)was ...Experimental investigation on the pull-out behaviour,including the withdrawal capacity,slip stiffness and inter-facial shear stress,of axially loaded screwed-in threaded rod embedded in cross laminated timber(CLT)was con-ducted.Specimens with varying embedment length and different number of threaded rods were tested in this study.To prevent premature splitting failure of timber,some specimens were reinforced in the direction perpen-dicular to the timber grain with self-tapping screws.Test results showed that the screwed-in threaded rod con-nections exhibited good pull-out behaviour with high withdrawal capacity and slip stiffness.Within a certain range,the withdrawal capacity increases considerably with the increase of embedment length,while the average interfacial shear stress shows the opposite tendency.The self-tapping screws played an important role on reducing the splitting of the timber and improving the withdrawal capacity and slip stiffness of the screwed-in threaded rod.Additionally,for the specimens with self-tapping screw reinforcements,the improvement of withdrawal capacity and stiffness when increasing the number of threaded rods are much more obvious than that of the speci-mens without the self-tapping screws,due to the change of failure modes.展开更多
Single-fiber pull-out testing(SFPOT)methods are frequently used to evaluate the inter-facial adhesion between fiber and matrix in composite materials.To make such pull-out mea-surements,however,the length of embedded ...Single-fiber pull-out testing(SFPOT)methods are frequently used to evaluate the inter-facial adhesion between fiber and matrix in composite materials.To make such pull-out mea-surements,however,the length of embedded fiber must be small enough so that the fiberdoes not break before it is pulled freely.This is difficult to achieve by conventional methodswith fibers of small diameter,such as the carbon fibers.In this paper,a fiber pull-out ex-periment is described.Specialized apparatus in our laboratory,as well as this technique forsample preparation are discussed in detail.The interracial shear strength of carbon fiber/resin matrix composites is analyzed quantitatively by using the finite-element method.TheSFPOT system has been proved to be an available means for the study of interracial proper-ties for carbon fiber/resin matrix composites.展开更多
The reaction of earth to pull-out process of frictional rock bolts was here modeled by the distinct element method (DEM). Ten frictional bolts were prepared;the expanding shells of five bolts included convex edges and...The reaction of earth to pull-out process of frictional rock bolts was here modeled by the distinct element method (DEM). Ten frictional bolts were prepared;the expanding shells of five bolts included convex edges and the others had the shells with concave bits. The strength of bolts was measured by applying a standard pull-out test;the results confirmed that the strength of shells with convex edges was remarkably more than the strength of other shells. Furthermore, a two-dimensional DEM model of the test was developed by a particle flow code;the obtained results showed that the reaction of rock particles to the contacts occurring between the convex edges and earth was considerably more than those of the concave bits. In the other words, the convex edges transferred the pull-out force into a large area of the surrounded rock, causing these bolts to have the highest resistance against earth movements.展开更多
The effective utilisation of steel fibre reinforced concrete (SFRC) requires in-depth and detailed understanding of bonding mechanisms governing the tensile behaviour. In response to this demand, this study presents a...The effective utilisation of steel fibre reinforced concrete (SFRC) requires in-depth and detailed understanding of bonding mechanisms governing the tensile behaviour. In response to this demand, this study presents an empirical description of the axial force required to pull out a hooked end steel fibre from a cementitious matrix. It is based upon consistent experimental tests that show the force versus displacement plot is formed from a sequence of events in which partial and full debonding at the interface is followed by bending of the hook knee to raise the force to its maximum. A loss of peak force occurs with the reversed plasticity involved in a full straightening of the fibre that precedes the rapid sliding to its full removal under a falling force. The stages are assembled in the said order with a piecewise connection between linear segments and a curve of exponential decay. A power law can be introduced to describe the knee bending stage if preferred. The normalised co-ordinates were adopted for the simple mathematical discontinuous function of the full pull-out process. Normalising force and displacement for hooked fibre is based upon the maximum values found for straight fibre pull out. This would apply to an overall embedded length of unity and a unit peak force for a full debonding of straight fibre in similar materials. For hooked fibre the normalised co-ordinates given refer to the initiation and duration of each event to be tabulated at fractions of the embedded length with multiples of that force. Such predictions are seen to be in good agreement with average pull-out response curves.展开更多
The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the typ...The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.展开更多
Suction caissons have been widely used as anchors and foundations for floating and fixed offshore platforms.The pull-out performance of conventional suction caissons (with upright walls) has been investigated by a num...Suction caissons have been widely used as anchors and foundations for floating and fixed offshore platforms.The pull-out performance of conventional suction caissons (with upright walls) has been investigated by a number of researchers.However,no attention has been paid to tapered suction caissons.This paper deals with the performance of tapered suction caissons under vertical pull-out loads.A numerical approach is used for this purpose.The numerical model is first verified against test data available for common upright caissons.The verified model is then used to study the pull-out performance of tapered suction caissons.It is noticed that the pull-out capacities exhibited by tapered suction caissons are in general considerably higher than those from their corresponding traditional upright caissons.To obtain an insight into this superior behaviour,effects from certain soil/caisson/drainage parameters on the pull-out capacity of tapered suction caissons are studied.Soil cohesion is noticed to have a linear improving effect on the capacity of both upright and tapered suction caissons.The soil internal friction angle is noticed to have an exponential increasing effect on the pull-out capacity.With a constant caisson diameter,an increase in the aspect ratio is seen to particularly influence the pull-out capacity.With a constant caisson length,an increase in the aspect ratio is discovered to result in non-linear decrease in the pull-out capacity.Under undrained conditions,tapered models generally show less sensitivity to above mentioned soil/caisson parameters as compared with those under drained conditions.展开更多
An elastic analysis of an internal central crack with bridging fibers parallel to the free surface in an infinite orthotropic anisotropic elastic plane was performed. A dynamic model of bridging fiber pull-out of comp...An elastic analysis of an internal central crack with bridging fibers parallel to the free surface in an infinite orthotropic anisotropic elastic plane was performed. A dynamic model of bridging fiber pull-out of composite materials was presented. Resultingly the fiber failure is governed by maximum tensile stress, the fiber breaks and hence the crack extension should occur in self-similar fashion. By the methods of complex functions, the problem studied can be transformed into the dynamic model to the Reimann-Hilbert mixed boundary value problem, and a straightforward and easy analytical solution is presented. Analytical study on the crack propagation subjected to a ladder load and an instantaneous pulse loading is obtained respectively for orthotropic anisotropic body.By utilizing the solution, the concrete solutions of this model are attained by ways of superposition.展开更多
The pullout testing of geosynthetics is essential for studying interface interaction in the soil-reinforcement system. In this paper, a new method for testing interface properties of geotextiles is proposed. The inter...The pullout testing of geosynthetics is essential for studying interface interaction in the soil-reinforcement system. In this paper, a new method for testing interface properties of geotextiles is proposed. The interface frictional characters of two kinds of geotextiles (woven and needle-punched nonwoven) are investigated through pullout test. Nonwoven specimen has more wide variety of displacement along length than that of woven under the same pressure because of their different extensibility. The greater the elongation and deformation of specimens, the more evident the variations of displacement along reinforcement from front to pullout end. The greater the normal pressure, the smaller the displacement of every position along length with the same pullout load. The study focuses on the effects of the tensile modulus and the difference of pullout response between woven and nonwoven geotextiles.展开更多
Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)...Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)after fatigue resistance testing at different cycles and semidiameter of screw insertion area of micro-CT image was compared between the micro-dynamic and traditional pedicle screws.Methods Forty lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows:15 vertebrae underwent instant pull-out testing(group A,traditional vs.group B,micro-dynamic);15 vertebrae underwent pull-out test after 5000-cyclic fatigue loading(group C,traditional vs.group D,micro-dynamic);and 10 vertebrae underwent pull-out test after 10000-cyclic fatigue loading(group E,traditional vs.group F,micro-dynamic).All vertebrae that after fatigue loading were scanned by using micro-ct to check the semidiameter of screw insertion area.The PPF,normalized PPF(PPFn),bone mineral density(BMD)and diameter of screw insertion area were compared between all groups.Results The BMD showed a weak significant correlation with PPF(r=0.252,P=0.024).The PPF in groups A and B(P=0.485),and groups C and D(P=0.184)did not show significant difference.However,the PPF in group F was significantly greater than that measured in group E(P=0.005).The PPFn of groups A,C,and E significantly decreased as the number of cycles increased(P=0.015).Meanwhile,the PPFn of groups B,D,and F remained consistent regardless of the number of cycles(P=0.367). The semidiameter of traditional pedicle screw insertion area was significantly larger than that of micro-dynamic pedicle screw insertion area(P<0.001).Conclusions This study compared the performance of a micro-dynamic pedicle screw versus that of a traditional pedicle screw using pull-out testing and micro-CT.The results showed that the micro-dynamic pedicle screw provides similar resistance in lowcycle fatigue testing and favorable resistance in high-cycle fatigue testing versus the traditional pedicle screw.The micro-dynamic pedicle screw provides stronger fixation stability versus the traditional pedicle screw,especially in high-cyclic fatigue loading condition versus the traditional pedicle screws.展开更多
The nature of the pull-out system of carbon nanorope/polyethylene(CNRP/PE) composite is studied by using molecular dynamics approach. The deformation of the CNRP/PE composites in pull-out process is exhibited. The inf...The nature of the pull-out system of carbon nanorope/polyethylene(CNRP/PE) composite is studied by using molecular dynamics approach. The deformation of the CNRP/PE composites in pull-out process is exhibited. The influence of twisting deformation on the interfacial interaction of the composites is investigated. The results show that the energy of the pull-out system is conserved; and the interfacial bonding is weak resulting in a sliding failure of the CNRP inside PE matrix.展开更多
Stress equilibrium equations, boundary- and continuity-conditions were used to establish a theoretical model of progressive debonding with friction at the debonded interface. On a basis of the minimum complementary en...Stress equilibrium equations, boundary- and continuity-conditions were used to establish a theoretical model of progressive debonding with friction at the debonded interface. On a basis of the minimum complementary energy principle, an expression for the energy release rate G was derived to explore the interfacial fracture properties. An interfacial debonding crite- rion G≥Γi was introduced to determine the critical debond length and the bridging law. Numerical calculation results for fi- ber-reinforced composite SCS-6/Ti-6Al-4V were compared with those obtained by using the shear-lag models.展开更多
基金Project supported by the Guangdong Basic and Applied Basic Research Foundation of China(Nos.2022A1515010801 and 2023A1515012641)the Shenzhen Science and Technology Program of China(Nos.JCYJ20220818102409020 and GXWD20220811165158003)。
文摘The transient and static anti-plane problem of a rigid line inclusion pulled out from an elastic medium is studied.The singular integral equation method is used to solve the stress field.Under the static load,the stress intensity factor(SIF)at the inclusion tips increases with the medium length.The problem becomes equivalent to an inclusion in a medium with an infinite length when the length of the medium is 3.5times longer than that of the inclusion.However,under the transient load,the maximum value of the SIF occurs when the medium length is about two times the inclusion length.Besides,the relation between the pull-out force and the anti-plane displacement is given.The conclusions are useful in guiding the design of fiber reinforced composite materials.
基金supported by the European Research Fund for Coal and Steel in the AMSSTED Programme RFCR-CT-2013-00001
文摘Laboratory pull-out tests were conducted on the following rock bolts and cable bolts:steel rebars,smooth steel bars,fiberglass reinforced polymer threaded bolts,flexible cable bolts,IR5/IN special cable bolts and Mini-cage cable bolts.The diameter of the tested bolts was between 16 mm and 26 mm.The bolts were grouted in a sandstone sample using resin or cement grouts.The tests were conducted under either constant radial stiffness or constant confining pressure boundary conditions applied on the outer surface of the rock sample.In most tests,the rate of displacement was about 0.02 mm/s.The tests were performed using a pull-out bench that allows testing a wide range of parameters.This paper provides an extensive database of laboratory pull-out test results and confirms the influence of the confining pressure and the embedment length on the pull-out response(rock bolts and cable bolts).It also highlights the sensitivity of the results to the operating conditions and to the behavior of the sample as a whole,which cannot be neglected when the test results are used to assess the bolt-grout or the grouterock interface.
基金This research was sponsored by the National Natural Science Foundation of China(Grant Nos.51878344 and 51578284).
文摘Experimental investigation on the pull-out behaviour,including the withdrawal capacity,slip stiffness and inter-facial shear stress,of axially loaded screwed-in threaded rod embedded in cross laminated timber(CLT)was con-ducted.Specimens with varying embedment length and different number of threaded rods were tested in this study.To prevent premature splitting failure of timber,some specimens were reinforced in the direction perpen-dicular to the timber grain with self-tapping screws.Test results showed that the screwed-in threaded rod con-nections exhibited good pull-out behaviour with high withdrawal capacity and slip stiffness.Within a certain range,the withdrawal capacity increases considerably with the increase of embedment length,while the average interfacial shear stress shows the opposite tendency.The self-tapping screws played an important role on reducing the splitting of the timber and improving the withdrawal capacity and slip stiffness of the screwed-in threaded rod.Additionally,for the specimens with self-tapping screw reinforcements,the improvement of withdrawal capacity and stiffness when increasing the number of threaded rods are much more obvious than that of the speci-mens without the self-tapping screws,due to the change of failure modes.
基金the High Technology Research and Development Programme of China.
文摘Single-fiber pull-out testing(SFPOT)methods are frequently used to evaluate the inter-facial adhesion between fiber and matrix in composite materials.To make such pull-out mea-surements,however,the length of embedded fiber must be small enough so that the fiberdoes not break before it is pulled freely.This is difficult to achieve by conventional methodswith fibers of small diameter,such as the carbon fibers.In this paper,a fiber pull-out ex-periment is described.Specialized apparatus in our laboratory,as well as this technique forsample preparation are discussed in detail.The interracial shear strength of carbon fiber/resin matrix composites is analyzed quantitatively by using the finite-element method.TheSFPOT system has been proved to be an available means for the study of interracial proper-ties for carbon fiber/resin matrix composites.
文摘The reaction of earth to pull-out process of frictional rock bolts was here modeled by the distinct element method (DEM). Ten frictional bolts were prepared;the expanding shells of five bolts included convex edges and the others had the shells with concave bits. The strength of bolts was measured by applying a standard pull-out test;the results confirmed that the strength of shells with convex edges was remarkably more than the strength of other shells. Furthermore, a two-dimensional DEM model of the test was developed by a particle flow code;the obtained results showed that the reaction of rock particles to the contacts occurring between the convex edges and earth was considerably more than those of the concave bits. In the other words, the convex edges transferred the pull-out force into a large area of the surrounded rock, causing these bolts to have the highest resistance against earth movements.
文摘The effective utilisation of steel fibre reinforced concrete (SFRC) requires in-depth and detailed understanding of bonding mechanisms governing the tensile behaviour. In response to this demand, this study presents an empirical description of the axial force required to pull out a hooked end steel fibre from a cementitious matrix. It is based upon consistent experimental tests that show the force versus displacement plot is formed from a sequence of events in which partial and full debonding at the interface is followed by bending of the hook knee to raise the force to its maximum. A loss of peak force occurs with the reversed plasticity involved in a full straightening of the fibre that precedes the rapid sliding to its full removal under a falling force. The stages are assembled in the said order with a piecewise connection between linear segments and a curve of exponential decay. A power law can be introduced to describe the knee bending stage if preferred. The normalised co-ordinates were adopted for the simple mathematical discontinuous function of the full pull-out process. Normalising force and displacement for hooked fibre is based upon the maximum values found for straight fibre pull out. This would apply to an overall embedded length of unity and a unit peak force for a full debonding of straight fibre in similar materials. For hooked fibre the normalised co-ordinates given refer to the initiation and duration of each event to be tabulated at fractions of the embedded length with multiples of that force. Such predictions are seen to be in good agreement with average pull-out response curves.
文摘The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.
文摘Suction caissons have been widely used as anchors and foundations for floating and fixed offshore platforms.The pull-out performance of conventional suction caissons (with upright walls) has been investigated by a number of researchers.However,no attention has been paid to tapered suction caissons.This paper deals with the performance of tapered suction caissons under vertical pull-out loads.A numerical approach is used for this purpose.The numerical model is first verified against test data available for common upright caissons.The verified model is then used to study the pull-out performance of tapered suction caissons.It is noticed that the pull-out capacities exhibited by tapered suction caissons are in general considerably higher than those from their corresponding traditional upright caissons.To obtain an insight into this superior behaviour,effects from certain soil/caisson/drainage parameters on the pull-out capacity of tapered suction caissons are studied.Soil cohesion is noticed to have a linear improving effect on the capacity of both upright and tapered suction caissons.The soil internal friction angle is noticed to have an exponential increasing effect on the pull-out capacity.With a constant caisson diameter,an increase in the aspect ratio is seen to particularly influence the pull-out capacity.With a constant caisson length,an increase in the aspect ratio is discovered to result in non-linear decrease in the pull-out capacity.Under undrained conditions,tapered models generally show less sensitivity to above mentioned soil/caisson parameters as compared with those under drained conditions.
文摘An elastic analysis of an internal central crack with bridging fibers parallel to the free surface in an infinite orthotropic anisotropic elastic plane was performed. A dynamic model of bridging fiber pull-out of composite materials was presented. Resultingly the fiber failure is governed by maximum tensile stress, the fiber breaks and hence the crack extension should occur in self-similar fashion. By the methods of complex functions, the problem studied can be transformed into the dynamic model to the Reimann-Hilbert mixed boundary value problem, and a straightforward and easy analytical solution is presented. Analytical study on the crack propagation subjected to a ladder load and an instantaneous pulse loading is obtained respectively for orthotropic anisotropic body.By utilizing the solution, the concrete solutions of this model are attained by ways of superposition.
文摘The pullout testing of geosynthetics is essential for studying interface interaction in the soil-reinforcement system. In this paper, a new method for testing interface properties of geotextiles is proposed. The interface frictional characters of two kinds of geotextiles (woven and needle-punched nonwoven) are investigated through pullout test. Nonwoven specimen has more wide variety of displacement along length than that of woven under the same pressure because of their different extensibility. The greater the elongation and deformation of specimens, the more evident the variations of displacement along reinforcement from front to pullout end. The greater the normal pressure, the smaller the displacement of every position along length with the same pullout load. The study focuses on the effects of the tensile modulus and the difference of pullout response between woven and nonwoven geotextiles.
基金supported by the National Natural Science Foundation of China ( 31670957)
文摘Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)after fatigue resistance testing at different cycles and semidiameter of screw insertion area of micro-CT image was compared between the micro-dynamic and traditional pedicle screws.Methods Forty lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows:15 vertebrae underwent instant pull-out testing(group A,traditional vs.group B,micro-dynamic);15 vertebrae underwent pull-out test after 5000-cyclic fatigue loading(group C,traditional vs.group D,micro-dynamic);and 10 vertebrae underwent pull-out test after 10000-cyclic fatigue loading(group E,traditional vs.group F,micro-dynamic).All vertebrae that after fatigue loading were scanned by using micro-ct to check the semidiameter of screw insertion area.The PPF,normalized PPF(PPFn),bone mineral density(BMD)and diameter of screw insertion area were compared between all groups.Results The BMD showed a weak significant correlation with PPF(r=0.252,P=0.024).The PPF in groups A and B(P=0.485),and groups C and D(P=0.184)did not show significant difference.However,the PPF in group F was significantly greater than that measured in group E(P=0.005).The PPFn of groups A,C,and E significantly decreased as the number of cycles increased(P=0.015).Meanwhile,the PPFn of groups B,D,and F remained consistent regardless of the number of cycles(P=0.367). The semidiameter of traditional pedicle screw insertion area was significantly larger than that of micro-dynamic pedicle screw insertion area(P<0.001).Conclusions This study compared the performance of a micro-dynamic pedicle screw versus that of a traditional pedicle screw using pull-out testing and micro-CT.The results showed that the micro-dynamic pedicle screw provides similar resistance in lowcycle fatigue testing and favorable resistance in high-cycle fatigue testing versus the traditional pedicle screw.The micro-dynamic pedicle screw provides stronger fixation stability versus the traditional pedicle screw,especially in high-cyclic fatigue loading condition versus the traditional pedicle screws.
基金Funded by the National Natural Science Foundation of China(Nos.11172012 and 11472020)
文摘The nature of the pull-out system of carbon nanorope/polyethylene(CNRP/PE) composite is studied by using molecular dynamics approach. The deformation of the CNRP/PE composites in pull-out process is exhibited. The influence of twisting deformation on the interfacial interaction of the composites is investigated. The results show that the energy of the pull-out system is conserved; and the interfacial bonding is weak resulting in a sliding failure of the CNRP inside PE matrix.
基金Project (No. M503095) supported by the Natural Science Foundation of Zhejiang Province, China
文摘Stress equilibrium equations, boundary- and continuity-conditions were used to establish a theoretical model of progressive debonding with friction at the debonded interface. On a basis of the minimum complementary energy principle, an expression for the energy release rate G was derived to explore the interfacial fracture properties. An interfacial debonding crite- rion G≥Γi was introduced to determine the critical debond length and the bridging law. Numerical calculation results for fi- ber-reinforced composite SCS-6/Ti-6Al-4V were compared with those obtained by using the shear-lag models.
