Early esophageal cancer with mucosal bridging in the resting room: A case report

BACKGROUND Patients diagnosed with esophageal mucosal bridges often experience symptoms such as chest pain and dysphagia,which pose considerable challenges for endo-scopic surgical interventions.CASE SUMMARY We present a case involving early-stage esophageal cancer discovered in a resting room,notable for the rare manifestation of esophageal mucosal bridging.Following a comprehensive multidisciplinary discussion and the development of a treatment strategy,we proceeded with endoscopic submucosal dissection for the patient.During the procedure,we encountered operational challenges due to the presence of a diverticulum and a partial absence of the muscularis propria.To facilitate the retraction of a portion of the resected specimen,we utilized dental floss.Ultimately,we successfully excised the entire lesion.After a three-day period of fasting with a water-only diet,subsequent iodine water cholan-giography did not indicate any perforations,and the patient was advised to transition to a liquid diet.The patient was discharged five days post-operation.A follow-up endoscopy conducted three months later revealed scar-like changes in the mid-esophagus,with the patient reporting no significant discomfort.CONCLUSION In summary,although esophageal mucosal bridges are rarely documented,they should be considered in the differential diagnosis of mechanical dysphagia.Furthermore,endoscopic therapy represents a feasible approach for their mana-gement.

Understanding Bridging Sites and Accelerating Quantum Efficiency for Photocatalytic CO_(2) Reduction

We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.

Transarterial embolization is an acceptable bridging therapy to hepatocellular carcinoma prior to liver transplantation

BACKGROUND Hepatocellular carcinoma(HCC)is an aggressive malignant neoplasm that requires liver transplantation(LT).Despite patients with HCC being prioritized by most organ allocation systems worldwide,they still have to wait for long periods.Locoregional therapies(LRTs)are employed as bridging therapies in patients with HCC awaiting LT.Although largely used in the past,transarterial embolization(TAE)has been replaced by transarterial chemoembolization(TACE).However,the superiority of TACE over TAE has not been consistently shown in the literature.AIM To compare the outcomes of TACE and TAE in patients with HCC awaiting LT.METHODS All consecutive patients with HCC awaiting LT between 2011 and 2020 at a single center were included.All patients underwent LRT with either TACE or TAE.Some patients also underwent percutaneous ethanol injection(PEI),concom-itantly or in different treatment sessions.The choice of LRT for each HCC nodule was determined by a multidisciplinary consensus.The primary outcome was waitlist dropout due to tumor progression,and the secondary outcome was the occurrence of adverse events.In the subset of patients who underwent LT,complete pathological response and post-transplant recurrence-free survival were also assessed.RESULTS Twelve(18.5%)patients in the TACE group(only TACE and TACE+PEI;n=65)and 3(7.9%)patients in the TAE group(only TAE and TAE+PEI;n=38)dropped out of the waitlist due to tumor progression(P log-rank test=0.29).Adverse events occurred in 8(12.3%)and 2(5.3%)patients in the TACE and TAE groups,respectively(P=0.316).Forty-eight(73.8%)of the 65 patients in the TACE group and 29(76.3%)of the 38 patients in the TAE group underwent LT(P=0.818).Among these patients,complete pathological response was detected in 7(14.6%)and 9(31%)patients in the TACE and TAE groups,respectively(P=0.145).Post-LT,HCC recurred in 9(18.8%)and 4(13.8%)patients in the TACE and TAE groups,respectively(P=0.756).Posttransplant recurrence-free survival was similar between the groups(P log-rank test=0.71).CONCLUSION Dropout rates and posttransplant recurrence-free survival of TAE were similar to those of TACE in patients with HCC.Our study reinforces the hypothesis that TACE is not superior to TAE as a bridging therapy to LT in patients with HCC.

Making bridges between preclinical and clinical insights into age-related cognitive decline

With people living longer,the societal impact of age-related cognitive decline is becoming more pronounced(Crimmins,2015).Thus,it is increasingly important to comprehend the cognitive shifts linked to aging-whether they are physiological or pathological.

A Simple Egg Membrane Patch Bridging Method for Repairing Tympanic Membrane Perforation

Objective:To analyze the clinical effect of a simple egg membrane patch bridging method in repairing tympanic membrane perforation.Methods:A total of 93 tympanic membrane perforation patients admitted to the hospital between September 2022 and October 2023 were selected and divided into two groups according to the random number table method.The control group implemented the conventional treatment(n=46 cases),and the patch group adopted the simple egg membrane patch bridging method(n=47 cases).The healing rate of the tympanic membrane,the air-bone gap,the air conduction hearing threshold,the dry ear rate,and the incidence of complications in both groups were compared before and after treatment.Results:The healing rate of the tympanic membrane in the patch group was significantly higher than that of the control group(95.75%vs.76.09%),with P<0.05;there was no difference in the air-bone gap and air conduction hearing threshold levels between the two groups before treatment(P>0.05),and the hearing indexes of the patch group were significantly lower than those of the control group 3 months after treatment(P<0.05);the dry ear rate in the patch group was significantly higher than that of the control group after treatment(85.11%vs.67.39%),and the total incidence of complications was also significantly lower than that of the control group(6.38%vs.21.74%),with P<0.05.Conclusion:The simple egg membrane patch bridging method is effective in repairing tympanic membrane perforation,which can effectively improve patients’hearing levels and reduce the occurrence of post-treatment complications.Thus,it is worth popularizing and applying in the clinic.

Construction Monitoring and Analysis of Asymmetric Prestressed Concrete Bridge Crossing Multiple-Line Railways

Complex bridge structures designed and constructed by humans often necessitate extensive on-site execution,which carries inherent risks.Consequently,a variety of engineering practices are employed to monitor bridge construction.This paper presents a case study of a large-span prestressed concrete(PC)variable-section continuous girder bridge in China,proposing a feedback system for construction monitoring and establishing a finite element(FE)analysis model for the entire bridge.The alignment of the completed bridge adheres to the initial design expectations,with maximum displacement and pre-arch differences from the ideal state measuring 6.39 and 17.7 mm,respectively,which were less than the 20 mm limit required by the specification.Additionally,the stress monitoring showed that the maximum compressive stress was 10.44 MPa,which was 7.5%different from the finite element results,and better predicted the most unfavorable possible location.These results demonstrate that a scientifically rigorous construction monitoring and feedback system can ensure the safety of bridge construction and meet the expected construction standards.The findings presented in this paper provide valuable insights for bridge construction monitoring practices.

A Deep Learning Estimation Method for Temperature-Induced Girder End Displacements of Suspension Bridges

To improve the accuracy of thermal response estimation and overcome the limitations of the linear regression model and Artificial Neural Network(ANN)model,this study introduces a deep learning estimation method specifically based on the Long Short-Term Memory(LSTM)network,to predict temperature-induced girder end displacements of the Dasha Waterway Bridge,a suspension bridge in China.First,to enhance data quality and select target sensors,preprocessing based on the sigma rule and nearest neighbor interpolation is applied to the raw data.Furthermore,to eliminate the high-frequency components from the displacement signal,the wavelet transform is conducted.Subsequently,the linear regression model and ANN model are established,whose results do not meet the requirements and fail to address the time lag effect between temperature and displacements.The study proceeds to develop the LSTM network model and determine the optimal parameters through hyperparameter sensitivity analysis.Finally,the results of the LSTM network model are discussed by a comparative analysis against the linear regression model and ANN model,which indicates a higher accuracy in predicting temperatureinduced girder end displacements and the ability to mitigate the time-lag effect.To be more specific,in comparison between the linear regression model and LSTM network,the mean square error decreases from 6.5937 to 1.6808 and R2 increases from 0.683 to 0.930,which corresponds to a 74.51%decrease in MSE and a 36.14%improvement in R2.Compared to ANN,with an MSE of 4.6371 and an R2 of 0.807,LSTM shows a decrease in MSE of 63.75%and an increase in R2 of 13.23%,demonstrating a significant enhancement in predictive performance.

Performance Evaluation of Damaged T-Beam Bridges with External Prestressing Reinforcement Based on Natural Frequencies

As an evaluation index,the natural frequency has the advantages of easy acquisition and quantitative evaluation.In this paper,the natural frequency is used to evaluate the performance of external cable reinforced bridges.Numerical examples show that compared with the natural frequencies of first-order modes,the natural frequencies of higher-order modes are more sensitive and can reflect the damage situation and external cable reinforcement effect of T-beam bridges.For damaged bridges,as the damage to the T-beam increases,the natural frequency value of the bridge gradually decreases.When the degree of local damage to the beam reaches 60%,the amplitude of natural frequency change exceeds 10%for the first time.The natural frequencies of the firstorder vibration mode and higher-order vibration mode can be selected as indexes for different degrees of the damaged T-beam bridges.For damaged bridges reinforced with external cables,the traditional natural frequency of the first-order vibration mode cannot be used as the index,which is insensitive to changes in prestress of the external cable.Some natural frequencies of higher-order vibration modes can be selected as indexes,which can reflect the reinforcement effect of externally prestressed damaged T-beam bridges,and its numerical value increases with the increase of external prestressed cable force.

Travelling characteristics of road vehicles on single-level rail-cum-road bridge under the dynamic and aerodynamic impact of travelling trains

Aerodynamic and dynamic interference from trains is a key issue of concern for the safety of road vehicles travelling on single-level rail-cum road bridges.Based on the wind-road vehicle-train-bridge(WRTB)coupled vibration system developed herein,this study examines the dynamic characteristics when road vehicles meet trains in this situation.The influence of load combination,vehicle type and vehicle location is analyzed.A method to obtain the aerodynamic load of road vehicles encountering the train at an arbitrary wind speed is proposed.The results show that due to the windproof facilities and the large line distance between the railway and highway,the aerodynamic and dynamic influence of trains on road vehicles is slight,and the vibration of road vehicles depends on the road roughness.Among the road vehicles discussed,the bus is the easiest to rollover,and the truck-trailer is the easiest to sideslip.Compared with the aerodynamic impact of trains,the crosswind has a more significant influence on road vehicles.The first peak/valley value of aerodynamic loads determines the maximum dynamic response,and the quick method is optimized based on this conclusion.Test cases show that the optimized method can produce conservative results and can be used for relevant research or engineering applications.

High-intensity focused ultrasound ablation:An effective bridging therapy for hepatocellular carcinoma patients

AIM:To analyze whether high-intensity focused ultrasound(HIFU) ablation is an effective bridging therapy for patients with hepatocellular carcinoma(HCC).METHODS:From January 2007 to December 2010,49 consecutive HCC patients were listed for liver transplantation(UCSF criteria).The median waiting time for transplantation was 9.5 mo.Twenty-nine patients received transarterial chemoembolization(TACE) as a bringing therapy and 16 patients received no treatment before transplantation.Five patients received HIFU ablation as a bridging therapy.Another five patients with the same tumor staging(within the UCSF criteria) who received HIFU ablation but not on the transplant list were included for comparison.Patients were comparable in terms of Child-Pugh and model for end-stage liver disease scores,tumor size and number,and cause of cirrhosis.RESULTS:The HIFU group and TACE group showed no difference in terms of tumor size and tumor number.One patient in the HIFU group and no patient in the TACE group had gross ascites.The median hospital stay was 1 d(range,1-21 d) in the TACE group and two days(range,1-9 d) in the HIFU group(P < 0.000).No HIFU-related complication occurred.In the HIFU group,nine patients(90%) had complete response and one patient(10%) had partial response to the treatment.In the TACE group,only one patient(3%) had response to the treatment while 14 patients(48%) had stable disease and 14 patients(48%) had progressive disease(P = 0.00).Seven patients in the TACE group and no patient in the HIFU group dropped out from the transplant waiting list(P = 0.559).CONCLUSION:HIFU ablation is safe and effective in the treatment of HCC for patients with advanced cirrhosis.It may reduce the drop-out rate of liver transplant candidate.

Bridging and downstaging treatments for hepatocellular carcinoma in patients on the waiting list for liver transplantation

Several therapeutic procedures have been proposed as bridging treatments for patients with hepatocellular carcinoma(HCC)awaiting liver transplantation(LT).The most used treatments include transarterial chemoembolization and radiofrequency ablation.Surgical resection has also been successfully used as a bridging procedure,and LT should be considered a rescue treatment in patients with previous HCC resection who experience tumor recurrence or post-treatment severe decompensation of liver function.The aims of bridging treatments include decreasing the waiting list dropout rate before transplantation,reducing HCC recurrence after transplantation,and improving post-transplant overall survival.To date,no data from prospective randomized studies are available;however,for HCC patients listed for LT within the Milan criteria,prolonging the waiting time over 6-12 mo is a risk factor for tumor spread.Bridging treatments are useful in containing tumor progression and decreasing dropout.Furthermore,the response to pre-LT treatments may represent a surrogate marker of tumor biological aggressiveness and could therefore be evaluated to prioritize HCC candidates for LT.Lastly,although a definitive conclusion can not be reached,the experiences reported to date suggest a positive impact of these treatments on both tumor recurrence and post-transplant patient survival.Advanced HCC may be downstaged to achieve and maintain the current conventional criteria for inclusion in the waiting list for LT.Recent studies have demonstrated that successfully downstaged patients can achieve a 5-year survival rate comparable to that of patients meeting the conventional criteria without requiring downstaging.

High intensity focused ultrasound,liver disease and bridging therapy

High-intensity focused ultrasound(HIFU)is a noninvasive modality that uses an extracorporeal source of focused ultrasound energy.This technique was introduced by Lynn et al and is able to induce coagulative necrosis in selected tissues without damaging adjacent structures.Although HIFU has been studied for 50years,recent technological developments now allow its use for tumours of the liver,prostate and other sites.In liver disease,HIFU has been used to treat unresectable,advanced stages of hepatocellular carcinoma(HCC)and liver metastases.Hepatocellular carcinoma is a serious health problem worldwide and is endemic in some areas because of its association with hepatitis B and C viruses(in 20%of cases).Liver transplantation(LT)has become one of the best treatments available because it removes both the tumour and the underlying liver disease such as cirrhosis(which is present in approximately 80%of cases).The prerequisite for longterm transplant success depends on tumour load and strict selection criteria regarding the size and number of tumour nodules.The need to obtain the optimal benefit from the limited number of organs available has prompted strict selection criteria limited to only those patients with early HCC who have a better long-term outcome after LT.The so-called"bridging therapy"has the aim of controlling disease burden for patients who are on the organ transplant waiting list.Amongst various treatment options,transarterial chemoembolisation and radiofrequency ablation are the most popular treatment choices.Recently,Cheung et al demonstrated that HIFU ablation is a safe and effective method for the treatment of HCC patients with advanced cirrhosis as a bridging therapy and that it reduced the dropout rate from the liver transplant waiting list.In this commentary,we discuss the current value of HIFU in the treatment of liver disease,including its value as a bridging therapy,and examine the potential advantages of other therapeutic strategies.

Case of angina pectoris at rest and during effort due to coronary spasm and myocardial bridging

We present a case of a 71-year-old male who hadchest symptoms at rest and during effort. He had felt chest oppression during effort for 1 year,and his chest symptoms had recently worsened. One month before admission he felt chest squeezing at rest in the early morning. He presented at our institution to evaluate his chest symptoms. Electrocardiography and echocardiography failed to show any specific changes. Because of the possibility that his chest symptoms were due to myocardial ischemia,he was admitted to our institution for coronary angiography(CAG). An initial CAG showed mild atherosclerotic changes in the proximal segment of the left anterior descending coronary artery(LAD) and mid-segment of the left circumflex coronary artery. Subsequent spasm provocation testing using acetylcholine revealed a bilateral coronary vasospasm,which was relieved after the intracoronary infusion of nitroglycerin. Finally,a CAG showed myocardial bridging(MB) of the mid-distal segments of the LAD. Fractional flow reserve using the intravenous administration of adenosine triphosphate was positive at 0.77,which jumped up to 0.90 through the myocardial bridging segments when the pressure wire was pulled back. Thus,coronary vasospasm and MB might have contributed to his chest symptoms at rest and during effort. Interventional cardiologists should consider the presence of MB as a potential cause of myocardial ischemia.

Long-term outcomes of hepatocellular carcinoma that underwent chemoembolization for bridging or downstaging

BACKGROUND Prospective study of 200 patients with hepatocellular carcinoma(HCC)that underwent liver transplant(LT)after drug-eluting beads transarterial chemoembolization(DEB-TACE)for downstaging versus bridging.Overall survival and tumor recurrence rates were calculated,eligibility for LT,time on the waiting list and radiological response were compared.After TACE,only patients within Milan Criteria(MC)were transplanted.More patients underwent LT in bridging group.Five-year post-transplant overall survival,recurrence-free survival has no difference between the groups.Complete response was observed more frequently in bridging group.Patients in DS group can achieve posttransplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.AIM To determine long-term outcomes of patients with HCC that underwent LT after DEB-TACE for downstaging vs bridging.METHODS Prospective cohort study of 200 patients included from April 2011 through June 2014.Bridging group included patients within MC.Downstaging group(out of MC)was divided in 5 subgroups(G1 to G5).Total tumor diameter was≤8 cm for G1,2,3,4(n=42)and was>8 cm for G5(n=22).Downstaging(n=64)and bridging(n=136)populations were not significantly different.Overall survival and tumor recurrence rates were calculated by the Kaplan-Meier method.Additionally,eligibility for LT,time on the waiting list until LT and radiological response were compared.RESULTS After TACE,only patients within MC were transplanted.More patients underwent LT in bridging group 65.9%(P=0.001).Downstaging population presented:higher number of nodules 2.81(P=0.001);larger total tumor diameter 8.09(P=0.001);multifocal HCC 78%(P=0.001);more post-transplantation recurrence 25%(P=0.02).Patients with maximal tumor diameter up to 7.05 cm were more likely to receive LT(P=0.005).Median time on the waiting list was significantly longer in downstaging group 10.6 mo(P=0.028).Five-year posttransplant overall survival was 73.5%in downstaging and 72.3%bridging groups(P=0.31),and recurrence-free survival was 62.1%in downstaging and 74.8%bridging groups(P=0.93).Radiological response:complete response was observed more frequently in bridging group(P=0.004).CONCLUSION Tumors initially exceeding the MC down-staged after DEB-TACE,can achieve post-transplant survival and HCC recurrence-free probability,at five years,just like patients within MC in patients undergoing DEB-TACE.

Ganglioside promotes the bridging of sciatic nerve defects in cryopreserved peripheral nerve allografts

Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation. In this study, 10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation and were used for the repair of left sciatic nerve defects through allograft bridging. Three days later, 1 mL ganglioside solution （1 g/L） was sub- cutaneously iniected into the right hind leg of rabbits. Compared with non-injected rats, muscle wet weight ratio was increased at 2-12 weeks after modeling. The quantity of myelinated fibers in regenerated sciatic nerve, myelin thickness and fiber diameter were elevated at 4-12 weeks after modeling. Sciatic nerve potential amplitude and conduction velocity were raised at 8 and 12 weeks, while conduction latencies were decreased at 12 weeks. Experimental findings indicate that ganglioside can promote the regeneration of sciatic nerve defects after repair with cryopre- served peripheral nerve allografts.

High-intensity focused ultrasound ablation as a bridging therapy for hepatocellular carcinoma patients awaiting liver transplantation

The scarcity of liver grafts in Asia leads to a significant dropout of patients from liver transplant waiting lists, particularly patients with hepatocellular carcinoma and a low model for end-stage liver disease score. In order to reduce dropping out, different bridging therapies are employed. We report the use of high-intensity focused ultrasound ablation as a bridging therapy for a patient with hepatocellular carcinoma of stage two and an extremely low platelet count (20×10 9 /L). The ablation was successful. Blood tests showed that his liver function was similar before and after the treatment. No adhesion was encountered in the liver transplantation performed six months later.

Chitosan tube bridging autologous nerve segments for the repair of long-segmental sciatic nerve defects

BACKGROUND：Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain unclear.OBJECTIVE：To explore the feasibility and advantages of chitosan tube bridging autologous nerve segments for repairing 12-mm sciatic nerve defects in rats.DESIGN,TIME AND SETTING：A randomized,controlled,animal study using nerve tissue engineering was performed at the Animal Laboratory and Laboratory of Histology and Embryology,Liaoning Medical University from June 2008 to March 2009.MATERIALS：Chitosan powder was purchased from Jinan Haidebei Marine Bioengineering,China.METHODS：A sciatic nerve segment of approximately 8 mm was excised from the posterior margin of the piriformis muscle of Sprague Dawley rats.The two nerve ends shrank to form a 12-mm defect,and the nerve defect was repaired using a chitosan tube bridging autologous nerve segment （bridge group）,a chitosan tube-encapsulated autologous nerve segment （encapsulation group）,and a chitosan tube alone （chitosan tube alone group）,respectively.MAIN OUTCOME MEASURES：Histological and ultrastructural changes of the injured sciatic nerve;number of regenerated myelinated nerve fibers; nerve conduction velocity; leg muscle atrophy; and sciatic nerve functional index.RESULTS：At 4 months after implantation,the chitosan tube was absorbed.The tube was thin,but maintained the original shape,and vascular proliferation was observed around the tube.In the bridge group,regenerative myelinated nerve fibers were thick and orderly,with a thick myelin sheath and intact axonal structure.The number of myelinated nerve fibers and nerve conduction velocity were significantly greater compared with the other groups （P〈 0.01）.Moreover,nerve and muscle function was significantly improved following chitosan tube bridging autologous nerve segment treatment compared with the other groups （P〈 0.05 or P 〈 0.01）.CONCLUSION：Chitosan tube bridging autologous nerve segments exhibited better repair effects on nerve defects compared with chitosan tubeencapsulated autologous nerve segments and a chitosan tube alone.This method provided a simple and effective treatment for long-segmental nerve defects.

BRIDGING TOUGHENING OF EPOXY RESINS BY DISPERSED THERMOPLASTICS

The particulate toughening behaviour of epoxy resins modified by ductile thermoplastics is elucidated here by various bridging models. The experimental data for three different epoxy/PSF sys- tems are presented to illustrate the trend of the toughening characteristics. The conventional continuous bridging model is shown to have underestimated the effect of the particulate toughening. A joint appli- cation of the discrete bridging model and the multiple bridging model, however, shows promising result for modified epoxy systems such as AG80/DDS/PSF and E51/DDS/PSF. These models also provide quantitative descriptions for the crack pinning phenomenon previously observed by Fu and Sun in AG80/DDS/PSF.

Crystal Structure of Binuclear Bridging Complex[(dppf)_2Pd_2 (Ⅱ) (μ-Cl)_2] [PF_6]_2

The title complex [(dppf)2Pd2 (Ⅱ) (μ-Cl)2] [PF6]2 (C68H56-Fe2Pd2Cl2P6F12, Mr= 1682. 35) has been synthesized, the crystal and molecular struc-ture of the complex has been determined by X-ray diffraction method. The complex istriclinic space group P1 with a= 10. 453(3), b= 12. 918(4), c= 13. 449(4) A; α=86. 42(3), β=75. 57(2), γ=71. 58(3)°, Z= 1, Dc= 1. 68 g/cm3, μ(MoKα) = 12. 5cm-1, F(000) = 844. Final R= 0. 063 (Rw= 0. 082) for 4944 unique reflections with I≥3σ(I). The molecular configuration is centrosymmetric with symmetric double chlo-rine bridges.

DYNAMIC CRACK MODELS ON PROBLEM OF BRIDGING FIBER PULL-OUT OF COMPOSITE MATERIALS

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.