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We compared the outcomes of modified single-patch and two-patch surgical repair of complete atrioventricular septal defect (CAVSD) on left ventricular outflow tract (LVOT) diameter and on left atrioventricular valve (LAVV) coaptation.We reviewed retrospectively postoperative 2-dimensional echocardiograms of all CAVSD patients who underwent modified single-patch or two-patch repair between 2005 and 2011. We measured the leaflet coaptation length of the LAVV in the apical four-chamber view. The LVOT was measured in the long axis view.Fifty-one patients underwent CAVSD repair at a median age of 4 months (range, 1 to 9 months) (single-patch, n=29; two-patch, n=22). The images from 46 echocardiograms were adequate for analysis. Modified single-patch repair required significantly shorter bypass time (102.0±33.6 vs 152.9±39.5 minutes, p0.001) and ischemic time (69.0±21.7 vs 106.9±29.7 minutes, p0.001) than did two-patch repair. The indexed coaptation length of the septal and lateral leaflets was not different between single-patch and two-patch (3.1±2.3 vs 4.1±3.1 mm/m2, p=0.25; 2.3±2.3 vs 3.3±3.0 mm/m2, p=0.21). Indexed LVOT diameter was not different in the two groups (26.1±5.2 vs 28.5±7.1 mm/m2, p=0.22). There was no hospital or late death during the median follow-up time of 35 months (range, 1 to 69 months). Five patients underwent reoperation after single-patch repair (3 with residual ventricular septal defect [VSD] and LAVV regurgitation, 1 with residual VSD, 1 with pacemaker implantation). After the two-patch repair, 1 patient required reoperation for a residual VSD and right atrioventricular valve regurgitation (p=0.22).The modified single-patch repair was performed with significantly shorter bypass time and myocardial ischemic time. The postoperative LVOT diameter and LAVV leaflet coaptation length were not significantly different between techniques.

In this paper, we studied the fatigue behavior of a crack emanating from v-notched aluminum (7075-T6) plate. To analyze the fatigue life of notched specimens we applied variable cyclic block-loading sequences, including increasing (L-H) and decreasing (H-L) blocks. We also analyzed the effect of the stress ratio(R) on the fatigue life of aluminum specimen subjected to stepped variable cyclic loading. The obtained results show that the effect of stress ratio on the fatigue life is significant. The patch repair efficiency is found to be limited for increasing (L-H) loading blocks but is significantly high for decreasing (H-L) cyclic loading blocks.

The behaviour of steel members with fatigue cracks growing in the thickness direction and strengthened with an adhesively bonded composite patch is assessed in this paper both analytically and experimentally. Analytical models for two different fracture fatigue parameters, namely the stress magnification factor for the crack in the steel member and the energy release rate for debonding at the steel/adhesive interface, are developed based on finite element analyses. These models can be readily employed in fatigue calculations. In order to verify the analytical models, an experimental investigation is also carried out. To this end, fatigue tests of specially designed and prepared patched cracked steel specimens are carried out and crack growth data are found to correlate reasonably well with their analytically obtained counterparts.

Discrete galvanic anodes are traditionally embedded in the patch repairs of steel reinforced concrete (RC) structures to offer corrosion prevention. This research investigated the performance of galvanic anodes installed in the parent concrete surrounding the patch repair, in order to explore the performance of such a new arrangement and identify its potential for wide-scale application. This arrangement was tested on a RC multi-storey car park and a RC bridge, both suffering from chloride-induced corrosion of the reinforcement. The performance of the anodes was assessed using close-interval potential mapping for 215 days after installation. The results indicate that the anodes polarised the steel at a significant distance away from the patch repair interface, up to 600 mm in some cases. It illustrates that such an arrangement may be advantageous when repairing RC structures as the corrosion prevention can be targeted at the steel in the surrounding parent concrete, which is traditionally considered to be at higher risk due to incipient anode development.

Objectives Repair of a postinfarction ventricular septal defect (VSD) is a challenging procedure with a high risk of postoperative residual shunt and subsequent mortality. This retrospective study aimed to assess a modified infarct exclusion technique with a biventricular approach. Methods Nineteen consecutive patients who underwent the infarct exclusion procedure for VSD between 2002 and 2011 were reviewed. A biventricular approach (B group: 6 patients) and a left ventricular approach (L group: 13 patients) were studied by univariate analysis. Results The overall 30-day mortality was 15.8%, and was not different between the two groups (p = 0.94). Postoperative residual shunt was not observed in the B group (p = 0.21). The overall five-year survival rate was 79%, and there were no late deaths in the B group (p = 0.14). Conclusion The repair of postinfarction VSD can be safely performed by the infarct exclusion technique with a biventricular approach. This technique seems to reduce surgical mortality and prevents recurrence of the VSD. doi: 10.1111/jocs.12262 (J Card Surg 2014;29:181–185)

The majority of aircrafts structure cracks due to fatigue are thin gage metallic structures and secondary support structures. Beside lower fatigue strength, they may also occur due to mechanical defects, especially at weak area and for areas exposed to high repetitive force such as vibration, friction, acoustic load and tensile force. Normally, the Original Equipment Manufacturer (OEM) recommended the aircraft operator to repair the crack by typical patch or doublers repair technique which is formally known as Non-Flush Patch RepairScheme. However, the crack tends to reappear and tend to be more severe. The natural frequency and damping ratio of a structure which is treated with Typical Non-Flush Patch Repair, with and without Passive Damping Treatment (PDT) are studied using impulse based technique. Experimental data are presented to demonstrate the difference of damping ratio (ζ) among the test specimens. The cracked structure which has been treated with PDT on Non-Flush Repair Scheme has a better damping ratio and resonates at a different natural frequency. The experiment data generated from this study can be used as a basis to further the study on aircrafts structural repair scheme.

The image signal of intermittent high energy pulsed droplet transfer are acquired using high-speed camera systems and self-developed high-energy pulsed cold patch machine. Then, the droplet transfer characteristics in high-energy pulsed cold patch process were discussed. The results showed that in the high-energy pulsed cold patch repair process, welding wire and substrate surface were melted by instantaneous high voltage arc and dropwise droplet were formed. And the droplet jitter, roll by gravity and surface tension and then cooled and solidified rapidly, metallurgical fused at the end.

This work is focusing on the low velocity impact damage evaluation and the external patch repair techniques of carbon/epoxy UD and fabric laminate adopted developing aircraft. The impact damages of composite laminates of the carbon/epoxy UD and fabric are simulated by the drop-weight type impact test equipment. The damaged specimens are repaired using the external patch repair method after removing the damaged area. The compressive strength test and analysis results of the repaired impact damaged specimens are compared with the compressive strength test and analysis results of the undamaged specimens and the impact damaged specimens. Finally, through investigation of compressive strengths of the damaged specimens at different environmental conditions, the damage criteria for repairable design of both the impact damaged UD and fabric laminate structure are suggested.

Introduction:Massive rotator cuff tears are difficult to manage. A treatment option is the use of a synthetic patch as an interpositional bridge to restore the continuity of the cuff defect. The aim of this paper was to evaluate the early clinical results of these techniques compared with the standa

In order to cure asphalt pavement distresses caused by expansive soil subgrade, a new maintenance technology based on trenchless technology with the macromolecule polymer grouting was adopted. The technique principle of the macromolecule polymer grouting, grouting construction method, cold patch repair technology, and the evaluation of engineering treatment were studied. The results showed that the macromolecule polymer grouting technology is feasible used in asphalt pavement maintenance.

Background Patients born with a congenital diaphragmatic hernia (CDH) have a high mortality and morbidity. After discharge, complications and long-term morbidity are still encountered. This study describes the factors related to the surgical long-term outcomes in CDH survivors. Methods A cohort of CDH patients born between 2000 and 2014, with a minimum of two years follow up, were included in this retrospective study. Demographics, CDH specific characteristics, treatment, and long-term surgical outcome were evaluated using multivariate logistic regression analyses. Results 112 patients were included, with a mean follow up of 7.3 years (SD 3.8). The majority had primary repair, but 31% received patch repair. Recurrence was reported in 7% of all patients. However, recurrence risk increased for patients with extracorporeal membrane oxygenation (ECMO) treatment (ORadjusted: 6.3, 95% CI: 1.2–33.9). This risk was highest for patients needing both ECMO and patch repair (OR: 11.2, 95% CI: 2.3–54.1). Small bowel obstructions (SBO) were observed in 20% and was associated with patch repair (ORadjusted: 3.5, 95% CI: 1.2–10.0), but ECMO treatment seemed to reduce this risk (ORadjusted: 0.2, 95% CI: 0.0–1.0). Thoracic deformations (36%) was diagnosed most often after patch repair, especially when ECMO was needed (60%) as well. Conclusions This retrospective study shows that the incidence of surgical long-term morbidity of CDH is relatively high, with different factors accounting for this. Diaphragmatic hernia recurrence was strongest associated with ECMO treatment in combination with patch repair, while SBO's were associated with patch repair, with an unexpected protective effect of ECMO treatment. Type of study Retrospective comparative study - Level III evidence.

Sinus of Valsalva aneurysms are extremely rare, and usually of a congenital nature. There are few documented cases of this condition during pregnancy, which renders unclear the therapeutic options. We here report the case of a 26 years old pregnant woman who was referred to our cardiac center for the evaluation of a heart murmur. The two-dimensional transthoracic echocardiography allowed quickly to establishthe diagnosis of a ruptured sinus of Valsalva aneurysm into the right ventricle. A successful surgical correction of the ruptured aneurysm was performed with patch repair.

Several toughening mechanisms, such as fibre bridging, can occur during delamination of fibre reinforced composites. In structures made of composite bonded joints, delamination can occur either in the composite or in the adhesive layer. In the first case composite toughness might be affected by the presence of the adhesive, especially if the crack propagates nearby the bond layer. The interaction of an adhesive layer with the propagation of sub-surface delamination cracks within the adherent remains a mechanism which is not well understood. In this work, the mode I delamination behavior of Asymmetric Double Cantilever Beam bonded joint specimens is investigated and compared with bulk composite specimens in order to assess the influence of an adhesive layer. Fracture resistance measurements show that the bond layer considerably affects the steady state fracture toughness of the composite with a very significant reduction of the bridging contribution. This effect is extended to two different types of epoxy adhesive: different curing cycles and different elasto-plastic properties. The extent of mode II due to the asymmetric position of the crack starter and to the adhesive layer is assessed both experimentally and numerically, and found negligible for the considered configurations. Besides, it is demonstrated that the change of compliance of a specimen due to the presence of an adhesive layer has almost no effect on the delamination behavior. Using an inverse identification methodology, the parameters describing the bridging traction relation are determined for both joint and bulk specimens. It is found that the rate of decay of bridging tractions is significantly higher for joints compared to bulk specimens. Those identified tractions-separation relations are subsequently implemented in cohesive zone models to simulate delamination of each configuration. Load displacement and crack growth are successfully predicted, demonstrating that this method, which consists in identifying a cohesive model for a specific crack position offset in the presence of an adhesive layer, can be used for prediction purposes. Moreover, it is shown that the identified tractions based on the steady state strain measurements predict the strains at the transient phase of bridging development. The isolated fibres and bundles of fibres participating to bridging are quantitatively measured in both bulk and joint specimens, and results show that mostly isolated fibres participate to bridging in the case of joints, whereas they tend to congregate to form clusters in bulk specimens, which require much more energy to break. A 3D finite element model show that the elasto-plastic properties of the adhesive create a local perturbation of the stress field around the crack tip. A shielding effect of the adhesive layer has been ascertained, preventing stresses from spreading continuously. The changes of amplitude and the spatial repartition of stresses in the process zone compared to bulk specimens with the same geometry are highlighted.

Background Endoscopic perforations are surgically repaired by using an omentum patch. Omentum substitutes may have broader applications particularly in certain sites (eg, esophagus). Objective Evaluate a self-expandable foam matrix plug as a synthetic omentum substitute for repairing iatrogenic gastric perforations in a 4-week survival pig model. Design Experimental pilot study. Setting Laboratory. Intervention A laparoscopic plug repair of a 1-cm, full-thickness, gastric perforation was carried out by using either a polyurethane foam matrix plug (FMP, 8 animals) or an omentum plug (OP, 6 animals, control group). Main Outcome Measurements Follow-up endoscopy was carried out at 1 and 4 weeks. At necropsy, the perforation site was evaluated for adhesions and histology by using hematoxylin and eosin analysis. A portion of the implant was sent for bacterial and fungal culture. Results All procedures were technically simple and successful. Thirteen animals thrived well for 4 weeks. One animal from the FMP group died 3 days postoperatively from diffuse peritonitis because of a misplaced plug. All remaining FMPs were intact at 4 weeks and colonized with mixed bacteria, except one animal presenting with FMP migration after 1 week. Histologically, the FMP group had more prominent inflammation and suppuration as compared with the OP group, all limited to its adjacent tissue. Limitations Animal study. Conclusion The FMP offered a technically simple and feasible option for repairing iatrogenic gastric perforations. With effective sealing, the clinical outcome is similar to that of an omentum patch repair. Migration and inadequate sealing is a concern, which can lead to peritonitis and sepsis. Further development is needed to improve FMP performance.

Yapıştırma kaynak, lehim, perçin ve cıvata gibi farklı birleştirme yöntemlerine alternatif olarak kullanılan bir imalat yöntemidir. Özellikle bağlantı güvenirliliğinin önemli olduğu havacılık, uzay, otomotiv, inşaat ve deniz endüstrilerinde yapıştırıcıların kullanımı giderek artmaktadır. Yapıştırma yöntemi ile farklı özellik ve kalınlıklardaki malzemelerin bağlantılarında düzgün bir gerilme dağılımı sağlanarak, daha ekonomik ve daha hafif bir şekilde birleştirilebilir. Bu çalışmada, yapıştırma yöntemi ile farklı çentik geometrisine sahip parçaların tamirinin yapılması amaçlanmıştır. Bu amaçla, 2mm kalınlık, 25mm, 30mm, 35mm genişlik ve 112.5mm uzunluğa sahip alüminyum levhaların çentik ağız derinliği a=2mm, 4mm, 6mm ve çentik ağız yüksekliği b= 8mm olarak çentikler açılmış, daha sonra bu çentikli numuneler ebatları 40mm-25mm, 40mm-30mm, 40mm-35mm olan alüminyum yamalarla tamir edilmiştir. Elde edilen levhaların mekanik davranışları deneysel olarak incelenmiştir. Yama ile tamir edilmiş malzemelerin hasar yüklerinin yamasız malzemelerden daha fazla olduğu tespit edilmiştir., Adhesives are alternative joining techniques which can be used instead of different manufacturing methods such as bolt, rivet, weld, and solder. Especially the use of adhesives in aviation, space, automotive, building and marine industrials, for which the security of the joints needed, increases gradually. By using adhesively bonded joints, adherents which had different properties and thickness, acquiring regular stress distribution, can be joined more economically and slightly. The aim of the study is to repair the parts having different notch geometries with adhesive method. For this purpose, Aluminum alloy plates have the thickness of 2mm, the width of 25mm, 30mm and 35mm, the height of 112,5mm, and notch geometries with the height of 2mm, 4mm, 6mm and the width of 8mm on these plates were used, and then these notched samples were fixed with aluminium with the dimensions of 40-25mm,40-30mm,40-35mm. Finally, mechanical behaviour of these samples were examined with experimantal . As a result, it has been observed that failure loads of aluminum alloy plates repaired with patches are higher than unpatched aluminum alloy plates

A reduction in the in-service life spans of Gauteng roadways, have been seen due to increases in the formation and recurrence of potholes and patch repair failures. With much attention being focused on the technical causes, human factors adding to this problem have not received the attention it requires resulting in increased cost and risk to road users and asset owners. With roadway maintenance and management as the focus of the research, highlighting these human aspects and their influence on degrading roadway conditions within Gauteng was crucial. A survey performed during the research, showed that human factors pose as large a threat to asset service life and quality during the in-service maintenance period, as the technical aspects. Failure to consider both human aspects, as well as technical aspects during roadway maintenance management can therefore trap a roadway in a continual cycle of decline.

Fully encircled bonded composite repairs in pipelines have proven effective since their introduction in the early 1990s. These fully encircled repairs completely wrap around the pipe and the defect like a sleeve. As operators became more familiar with fully encircled repairs, and as their capabilities improved, application in larger pressure equipment became viable. Increase in equipment application size corresponds to an increase in material cost and application difficulty. As such, the effectiveness of smaller patch-type repairs is of interest. Patch-type repairs, as opposed to fully encircled repairs, do not completely surround the pipe and defect, but rather only a specified area over the defect. This paper presents pressure fatigue tests comparing the performance of fully encircled and patch-type repairs installed on 6-in. nominal steel pipe with through-wall defects. Repair strain, substrate strain, and fatigue life are compared for both the fully encircled and patch-type repair. Finite element simulation results are compared to the experimental results to validate existing material models and simulation boundary conditions.

Background A sinus of Valsalva aneurysm is a rare cardiac anomaly which may be acquired or congenital. The main associated symptoms are conduction disturbances, myocardial ischemia, and syncopes. Case presentation In this report we describe a 52-year-old Albanian woman from Kosovo with an unruptured aneurysm of 74×60 mm of the noncoronary sinus of Valsalva presenting dyspnea, jugular distension, and tachycardia due to cardiac compression. She underwent successful closure of the orifice and sinus remodeling with a Dacron patch. Conclusion To the best of our knowledge this is the largest reported isolated unruptured aneurysm of the coronary sinus causing severe compression of the cardiac chambers undergoing successful surgical correction.

[EN] The importance of the maintenance and rehabilitation of existing structures has grown significantly in recent years. This accompanied by a very important decrease in the investments in the new construction, again after a period of growth in the number of constructed buildings. These facts have motivated that, currently, there is a large park of buildings need to be repaired and strengthened. The columns are the elements which failure may cause a complete collapse of the structure. In the case of reinforced concrete columns, it is possible to intervene well by means of a strengthening or a repair, whose goal will be to increase or to maintain its resistance, respectively. In fact, the repair of damages of different scope and magnitude on the outside of a column by means of repair mortars is an operation very usual in rehabilitation works. There are even European standards that prescribe the characteristics of the mortars to be used. Despite this, there are no references to study the effectiveness of a repair in reinforced concrete columns, which gives rise to a large uncertainty in the level of security that is reached in the repaired element. This lack of experimental results, together with the importance of this type of the action is that has motivated this investigation, which has studied the effectiveness of repair, using pre-bagged concrete repair mortars, of columns subjected to axially loaded. It has been determined the influence of the different geometric, mechanical and construction variables that they affect to the repair in the compressive strength of the column repaired. In order to do so, an experimental study has been realized in laboratory, in which the three most frequent cases of repair have been tested: complete repair of 4 sides, complete repair of one side and patch repair, with the variables raised in this investigation, kind of mortar (Class R3 and R4) and use or not of bonding primer. The final aim of this investigation will be to determine the efficacy of the repair according to the conditions in which it has been realized and to obtain a series of basic rules of design and execution of the repair. The results are analyzed and compared with the columns pattern, undamaged section without repair. The results of the investigation carried out indicates that repairs carried out with mortar Class R3 presented excellent results, while mortar Class R4, for the tested columns, only restores partially load-carrying capacity. In the case of the repair to 4 sides, if used a mortar Class R4 the load-carrying capacity on the column repaired only reached 64% of the original. In the case of the repair to 4 sides with mortar Class R3, the use of bonding primer does not have significant influence on the recovery of the load-carrying capacity. Not this way if there uses a mortar Class R4, where the use of a bonding primer improves significantly the result. Patch repair restores practically the load-carrying capacity of the structural element for both mortars (R3 and R4). In this case the use of bonding primer only has significant influence in the repair using mortar Class R4, showing an improvement of 9% more than if bonding primer is not used. In the complete repair of one side whit mortar Class R3 restores 97% of the load-carrying capacity loss while with mortar Class R4 only reaches to 66%, and without influence of the use or not of bonding primer. These results highlight the importance of the choice of the system, method and materials of the repair. These must be compatible with the materials and the state of the original structure., [ES] En los últimos años ha crecido de manera significativa la importancia del mantenimiento y rehabilitación de estructuras existentes. Esto viene acompañado de un descenso muy importante en las inversiones en la construcción de obra nueva, después de un periodo de crecimiento en el número de edificios construidos. Estos hechos han motivado que, actualmente, exista un gran parque de edificaciones con necesidad de ser reparado o reforzado. Dentro de un edificio, los pilares son los elementos cuyo fallo puede provocar un colapso completo de la estructura. En el caso de los pilares de hormigón armado, se puede intervenir bien mediante un refuerzo o una reparación, cuyo fin será incrementar o mantener su resistencia, respectivamente. De hecho, la reparación de daños de diverso alcance y magnitud en la parte externa de un pilar mediante morteros de reparación es una operación muy habitual en obras de rehabilitación. Incluso existen normas europeas que prescriben las características de los morteros a utilizar. Pese a ello, no se dispone de referencias que estudien la efectividad de una reparación en pilares de hormigón armado, lo que da lugar a una gran incertidumbre en el grado de seguridad que se alcanza en el elemento reparado. Esta falta de resultados experimentales, junto con la importancia de este tipo de actuaciones es la que ha motivado esta investigación, en la que se ha estudiado la efectividad de la reparación, mediante morteros predosificados, de pilares sometidos a compresión centrada. Se ha determinado la influencia de las distintas variables geométricas, mecánicas y constructivas que afectan a la reparación en la resistencia a compresión del pilar reparado. Para ello se ha realizado un estudio experimental en laboratorio, en el que se han ensayado los tres casos de reparación más frecuentes en la práctica: reparación integral a cuatro caras, reparación integral a una cara y reparación por parcheo, con las variables planteadas en esta investigación, clase de mortero (Clases R3 y R4) y utilización o no de puente de unión. El objetivo final de esta investigación será determinar la eficacia de la reparación en función de las condiciones en las que se ha realizado y obtener una serie de reglas básicas de diseño y ejecución para la reparación. Los resultados son analizados y comparados con los pilares patrón, sección intacta sin reparación. De los resultados de la investigación realizada se desprende que, las reparaciones realizadas con mortero Clase R3 presentan unos excelentes resultados, mientras que el mortero Clase R4, para los pilares ensayados, únicamente restituye de forma parcial la capacidad portante. Para el caso de la reparación a 4 caras, si se emplea un mortero Clase R4 la capacidad portante del pilar reparado tan sólo alcanza un 64% de la original. Para el caso de reparación de las 4 caras con mortero Clase R3, el empleo de un puente de unión no tiene una influencia significativa en la recuperación de la capacidad portante. No así si se emplea un mortero Clase R4, donde el empleo de un puente de unión mejora significativamente el resultado. La Reparación por Parcheo prácticamente restaura la capacidad portante del elemento estructural para ambos morteros (R3 y R4). En este caso la utilización del puente de unión solo tiene influencia significativa en la reparación mediante mortero Clase R4, presentando una mejoría de un 9% más que si no se utiliza el puente de unión. En la Reparación Integral a 1 Cara con mortero Clase R3 se restituye un 97% de la capacidad portante perdida mientras que con mortero Clase R4 tan solo se llega a un 66%, y sin influencia de la utilización o no del puente de unión. Estos resultados resaltan la importancia de la elección del sistema, método y materiales de la reparación. Estos deben ser compatibles con los materiales y el estado de la estructura original., [CAT] En els últims anys ha crescut de manera significativa la importància del manteniment i rehabilitació d'estructures existents. Açò ve acompanyat d'un descens molt important en les inversions en la construcció d'obra nova, després d'un període de creixement en el nombre d'edificis construïts. Estos fets han motivat que, actualment, existisca un gran parc d'edificacions amb necessitat de ser reparat o reforçat. Dins d'un edifici, els pilars són els elements la fallada dels quals pot provocar un col·lapse complet de l'estructura. En el cas dels pilars de formigó armat, es pot intervindre bé per mitjà d'un reforç o una reparació, el fi de la qual serà incrementar o mantindre la seua resistència, respectivament. De fet, la reparació de danys de divers abast i magnitud en la part externa d'un pilar per mitjà de morters de reparació és una operació molt habitual en obres de rehabilitació. Inclús hi ha normes europees que prescriuen les característiques dels morters a utilitzar. A pesar d'això, no es disposa de referències que estudien l'efectivitat d'una reparació en pilars de formigó armat, la qual cosa dóna lloc a una gran incertesa en el grau de seguretat que s'aconseguix en l'element reparat. Esta falta de resultats experimentals, junt amb la importància d'este tipus d'actuacions és la que ha motivat aquesta investigació, en la que s'ha estudiat l'efectivitat de la reparació, per mitjà de morters predosificats, de pilars sotmesos a compressió centrada. S'ha determinat la influència de les distintes variables geomètriques, mecàniques i constructives que afecten la reparació en la resistència a compressió del pilar reparat. Per a això s'ha realitzat un estudi experimental en laboratori, en el que s'han assajat els tres casos de reparació més freqüents en la pràctica: reparació integral a quatre cares, reparació integral a una cara i reparació per parcheo, amb les variables plantejades en esta investigació, classe de morter (Classes R3 i R4) i utilització o no de pont d'unió. L'objectiu final d'esta investigació serà determinar l'eficàcia de la reparació en funció de les condicions en què s'ha realitzat i obtindre una sèrie de regles bàsiques de disseny i execució per a la reparació. Els resultats són analitzats i comparats amb els pilars patró, secció intacta sense reparació. Dels resultats de la investigació realitzada es desprén que, les reparacions realitzades amb morter Classe R3 presenten uns excel·lents resultats, mentres que el morter Classe R4, per als pilars assajats, únicament restituïx de forma parcial la capacitat portant. Per al cas de la reparació a 4 cares, si s'empra un morter Classe R4 la capacitat portant del pilar reparat tan sols aconseguix un 64% de l'original. Per al cas de reparació de les 4 cares amb morter Classe R3, l'ocupació d'un pont d'unió no té una influència significativa en la recuperació de la capacitat portant. No així si s'empra un morter Classe R4, on l'ocupació d'un pont d'unió millora significativament el resultat. La Reparació per Parcheo pràcticament restaura la capacitat portant de l'element estructural per a ambdós morters (R3 i R4). En este cas la utilització del pont d'unió només té influència significativa en la reparació per mitjà de morter Classe R4, presentant una millora d'un 9% més que si no s'utilitza el pont d'unió. En la Reparació Integral a 1 Cara amb morter Classe R3 es restituïx un 97% de la capacitat portant perduda mentres que amb morter Classe R4 tan sols s'arriba a un 66%, i sense influència de la utilització o no del pont d'unió. Estos resultats ressalten la importància de l'elecció del sistema, mètode i materials de la reparació. Aquestos han de ser compatibles amb els materials i l'estat de l'estructura original., Ortega Palanco, AI. (2016). Contribución al estudio del comportamiento de pilares de hormigón armado reparados mediante morteros predosificados sometidos a comprensión centrada [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/62583., TESIS

Cracking of repair material due to restraint of shrinkage could hinder the intended extension of serviceability of repaired concrete structure. The availability of model to predict shrinkage stress under restraint condition will be useful to assess whether repair material with particular deformation properties is resistance to cracking or not. The accuracy in the prediction will depend upon reliability of the model, input parameters, testing methods used to characterize the input parameters, etc. This paper reviews a variety of models to predict shrinkage stress in patch repair system. Effect of creep and composite action to release shrinkage stress in the patch repair system are quantified and discussed. Accuracy of the models is examined by comparing predicted and measured shrinkage stress. Simplified model to estimate shrinkage stress is proposed which requires only shrinkage property of repair material as an input parameter.

Fatigue problems become an important topic in the maintenance of aircraft structures. Efficient repair technique, called composite patch repair, was used to reinforce the damaged structures and extend the service life. In this paper, using empirical approach, the effect of composite patch repair on fatigue crack growth was investigated on 7050 aluminum alloy. In additional, loading parameters associated with patch repair (Graphite/Epoxy) was studied in order to show their influence on fatigue life and fatigue crack growth rate, namely stress ratio. Results provide an increasing in fatigue life and fatigue crack growth rate in increased stress ratio. A delayed in fatigue life and diminution of FCGRs is the results of composite patch repair. Effect of patch repair was shown highly at high stress intensity factor when maximum applied loading is kept constant.

Attention towards optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy utilized to correct functional mitral regurgitation or systolic anterior motion in complex mitral valve repairs. This article describes a system for investigating the redistribution of chordae tendineae tension as a reflection of altered stress distribution of the valve leaflet following patch augmentation.An in vitro test setup was constructed to hold native porcine mitral valves containing an annulus and papillary muscle positioning system. The alterations caused by patch augmentation should be visual from both the atrial and ventricular views. Ventricular pressure was regulated stepwise in a range of 0-150 mmHg. To test the system, the anterior mitral leaflet was extended by a pericardial patch sutured to the mid/basal part of the leaflet, and the chordae tendineae force was measured as the ventricular pressure was applied.The system demonstrated the capacity to hold native porcine mitral valves and introducing patch repairs according to clinical practice. The porcine mitral valve test setup indicated strong correlation between the forces in the mitral valve secondary chordae tendineae and the applied transvalvular pressure (RThis test setup proved the ability to obtain normal mid-systolic mitral valve function, secondary chordae force measurements, and important preservation of the visual access: Hence, obtaining the pressure-force relationship as well as identifying any shift of the secondary chordae insertion point on the anterior leaflet relative to the coaptation zone was made possible.

Adhesive bonded joints are used in the assembling of structural parts, especially of those which are made from dissimilar materials. Lightweight fibre reinforced polymer composites and other adhesive bonded components represent a major proportion of a modern aircraft. Bonded patch repair technology has been widely used to repair cracked thin-walled structures to extend their service life, because a correctly executed repair significantly enhances the structural performance. In practice, the single-sided bonded patch repair is the most used because a good solution like the double-sided repair may not be an option if the access to the structure is only available from one side. This paper presents a relatively simple and effective design procedure for the single strapped bonded joints. Also, the influence of various geometrical parameters of the joint is evaluated. The analytical development is validated based on nonlinear finite element analyses.

An accurate and practical modeling technique is proposed to analyze cracked metal plates with patch repair. In the single-model approach, a p -convergent high-precision element is developed with three-dimensional elasticity theory. Whereas, in the mixed-model approach, a p -convergent transition element is developed to connect the p -convergent high-precision elements for threedimensional response and p -convergent ESL (equivalent single layer) elements for two-dimensional response. For the developed elements, two- and three-dimensional virtual crack closure techniques based on linear elastic fracture mechanics are modified to estimate the stress intensity factor. Modeling simplicity and calculation efficiency of the mixed-model approach using the p -convergent transition elements is shown for the analysis of patch repaired plates. Some results of present analysis are verified by comparison with published results. Also, performance of analysis using the proposed technique with simplicity and efficacy of modeling is investigated for patch repaired plates with respect to a number of parameters such as thicknesses of patch and adhesive, patch size, single-sided patch vs. double-sided patch.

Patch repair is often applied to the concrete structure deteriorated by the chloride ions. However, the macrocell corrosion may be formed, when there are a lot of chloride ions in the existing concrete. The steel corrosion in concrete progresses while depending the time. Therefore, it is effective to monitor at any time-interval. Based on the above backgrounds in this study, the analyzing method of the corrosion current is developed, to monitor the protection effect after the patch repair. The experiments are investigated in two steps. Firstly, the corrosion currents between measured from cathode to anode using the specimen with the special divided steel bar, and analyzed by this developed method, are compared. Secondly, the analyzed values and the actual corrosion or no-corrosion areas are compared. As results, 1) the analyzed values are equal to the measured values at these investigations ; 2) the analyzed corrosion area is equal to the actual corrosion area. It can be judged that quantitative monitoring method for the protect effect after the patch repair is developed.

A 69-year-old male patient underwent double-patch repair for a postinfarction ventricular septal defect (VSD). He returned five months later with an abscess in the area of a postoperative hematoma between the patch and the left ventricle. The abscess was drained and the ventricles were successfully reconstructed. Intracardiac hematoma after double-patch repair of postinfarction VSD should be closely followed up and, if there are any infection signs, aggressive surgical management should be performed. (J Card Surg 2010;25:676-679)

Polyethylene (PE) gas pipes can be jointed together by electrofusion PE fittings, which have sockets that are fused onto the pipe. Additionally, electrofused PE patches can be used to repair defected pipes. When these pipelines are buried under the ground, they can experience sever local stresses due to the presence of pipe joints, which is superimposed on the other effects including the soil-structure interaction, traffic load, soil&rsquo, s column weight, a uniform internal pressure, and thermal loads imposed by daily and/or seasonal temperature changes. The present contribution includes two cases. At first, stress variations in buried polyethylene gas pipe and its socket due to the aforementioned loading condition is estimated using finite element. The pipe is assumed to be made of PE80 material and its jointing socket material is PE100. Afterward, the effects of aforementioned thermo-mechanical loads on the stress distribution in patch repaired buried pipes are well investigated. The soil physical properties and the underground polyethylene pipe installation method are based on the American association of state highway and transportation officials and American society for testing and material standards. The computer simulation and analysis of stresses are performed through the finite element package of ANSYS Software. Stress concentrations can be observed in both components due to the presence of the socket or the repair patch. According to the results, the electrofusion sockets can be used for joining PE gas pipes even in hot climate areas. The maximum values of these stresses happen to be in the pipe. Also, the PE100 socket is more sensitive to a temperature drop. Additionally, all four studied patch arrangements show significant reinforcing effects on the defected section of the buried PE gas pipe to withstand applied loads. Meanwhile, the defected buried medium density polyethylene (MDPE) gas pipe and its saddle fused patch can resist the imposed mechanical and thermal loads of +22 &deg, C temperature increase.

This study experimentally examined the influence of patch repair materials on the electrochemical desalination method for reinforced concrete. The experimental parameters are the electrical resistivity and the repair area ratio of the patch repair materials. The evaluation items were the amount of desalination and the current density distribution at the surface of the rebar. In addition, an assessment method to estimate the amount of desalination by using core samples obtained from an existing member was proposed. Experiment results showed that the current density at the surface of a rebar increased near the boundary between the patch repair material and the concrete, and that the distribution of current density depended on the electrical resistivity and the repair area ratio of the patch repair materials. Moreover, the amount of desalination increased as the electrical resistivity of patch repair materials increased.

Development of a small scale aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all the composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has s disadvantage which is very weak against impact due to foreign object damages. Therefore the aim of this study is focusing on the damage evaluation and repair techniques of the aircraft composite structure. The damages of composite laminates including the carbon/epoxy UD laminate and the carbon/epoxy fabric face sheets-honeycomb core sandwich laminate were simulated by a drop weight type impact test equipment and the damaged specimen were repaired using the external patch repair method after removing damaged area. The compressive strength test and analysis results after repairing the impact damaged specimens were compared with the compressive strength test and analysis results of undamaged specimens and impact damaged specimens. Finally, the strength recovery capability by repairing were investigated.

The aim of this contribution is the optimization of some parameters of the composite patch repair technique (CPR). This technique is mainly used by the aircraft industry, as it offers high reliability, short repair times and reduced cost in compare to other methods, such as the riveted joints. CPR consists of adhesively bonding thin composite patches over cracked or corroded areas with heat supply. As the polymer-matrix composite patch is heated, it cures and toughens. Proper curing insures structural reliability of the repair. Short duration curing cycles are of great importance for the aircraft availability. With the use of Genetic Algorithms, we design minimum time curing cycles. The optimization is subjected to the following constraints: (1) Maximum allowed temperature in order to avoid residual stresses, (2) Minimum temperature in order to initiate the cure reaction, (3) Sufficient degree of cure at the end of the process and (4) Maximum heat generation rate that can be achieved by the device. Our design vector contains the duration of the plateau stage of the cure cycle and the characteristic thermal profile. The degree of cure is estimated with the use of the Kamal cure rate model for thermosetting polymers. For the numerical time integration of the cure rate equation, a second order, implicit Runge-Kutta scheme is employed.

The basic ideology involved behind this experimental scheme was to investigate the observed re-corrosion of the repaired reinforced concrete patches in actual field concrete works. From the experiment results it was found that the specimens having no chloride content at the middle portion showed high corrosion potential, and chloride-contaminated both sides of the specimen showed even more corrosion than before being repaired due to the separation of anode and cathode and development of a macro-cell. The research indicates that much of the needed research should focus on identification of corrosion mechanisms to effectuate the successful patch repair in reinforced concrete structures.

The current work focuses on the testing of a novel material used as an adhesive film in Composite Patch Repair (CPR). A series of Differential Scanning Calorimetry (DSC) results along with various curing cycles not only led to the optimum material composition but also demonstrated the compatibility to the composite pre-impregnated patches. This in turn was subjected to mechanical testing including shear strength measurements. The substrate was chosen to be 2017 T 4 aluminium alloy which is customarily used in the aerospace industry, taking into account that CPR is a technique mainly applied in this field. The subsequent surface preparation of the specimens was investigated for the specified context resulting to the selection of the Ferric Sulphate Sulphuric acid etching process. Finally, a series of specimens representing actual skin repairs were created and subjected to cyclic loading, specifying the suitability of the novel material, compared to commercially available materials.

Although bonded composite patches often offer a far more effective repair than conventional mechanically fastened patches, full credit can not be given for their effectiveness in reducing crack growth when used to repair flight safety structure. This is because of the lack of non-destructive techniques to detect bonds with poor long-term integrity and ability to predict the likelihood and rate of patch disbonding. Structural health monitoring (SHM) may overcome this limitation, since patch health can be monitored on a continuous basis. After discussing some of the requirements and options for structural health monitoring of bonded repair patches, a case history is presented on the application of a simple strain-based SHM approach for monitoring the boron/epoxy patch repair of a critical fatigue crack in an F-111C wing. The effectiveness of the strain-based SHM approach is demonstrated, and improvements which would reduce its limitations and raise its practicality to the level (TRL8) where it could be used for in- flight application are discussed. Conventional strain gauges were used in the SHM system which, although found effective, have several limitations. A study on the option of using Bragg grating optical fibres as strain sensors is briefly described. Finally brief details are provided on an alternative longer-term approach and study to use acousto-ultrasonics as the basis of the SHM system.

症例は63歳の男性．急性B型大動脈解離発症4年後に，胸腹部大動脈瘤に対して，人工血管を用いてパッチ形成術および腹腔動脈再建術を施行した．その8年後に吻合部仮性動脈瘤を認め再手術となった．左第8肋間開胸にて動脈瘤に到達し左大腿動静脈より送脱血管を挿入し下半身部分体外循環下に手術を行った，中枢側はTh8レベルで，末梢側は上腸間膜動脈直上で遮断し動脈瘤を切開した．中枢側吻合部が離解し仮性動脈瘤を形成していた．パッチをすべて除去し人工血管置換術を施行した．肋間動脈は2対人工血管間置法にて再建し，腹腔動脈も同様に再建した．術後経過良好で対麻痺も認めず，術後12日目に軽快退院となった．本例は初回手術時にパッチ形成術を選択し対麻痺を回避し得た症例であるが，遠隔期に吻合部瘤を合併した．このような合併症を考慮すると，可能な限り脊髄虚血予防を行った上で人工血管置換術を選択するのが妥当と考える．

One of the most challenging problems in clinical surgery is management of an extensive duodenal injury. In its management, there are limitations in using jejunal serosal patch and other conventional methods in specific conditions. This study was performed to compare treatment of large duodenal defects by a gallbladder serosal patch and the gallbladder mucosal patch in a dog as an animal model.A duodenal defect (2 cm, about 50% of the total circumference) was created in the second portion of the duodenum in eight dogs. The animals were divided into two equal groups, with group 1 undergoing serosal patch repair and group 2 undergoing mucosal patch repair. The macroscopic and microscopic healing features of the gallbladder serosal and mucosal patch were compared.None of the dogs died due to surgical complications. The whole grafted area was covered by neomucosa at the end of the third week in all animals with the gallbladder serosal patch (group 1). In this group, the scar was small; no significant narrowing of lumen was noted and serosal healing was uniformly complete. In histological examination, a complete coverage of the gallbladder serosal patch by neomucosa consisting of columnar epithelium with short villous formations was observed. In mucosal patch models (group 2), complete epitheliazation, mild fibrosis, and incomplete repair were visible. In histological examination, severe inflammation was noticed too.In patients with multiple trauma affecting upper gastrointestinal tracts, use of the gallbladder serosal patch method is easy and reliable. So it may be considered in the surgical management of large duodenal defects, which cannot be repaired by available conventional methods.

Patch repair of cracked structures has become a rapidly grown technology. The major function of a repair is to reduce the stress intensity factor at the crack-tip. Calculation of stress intensity factor of a repaired crack has been performed by analytical and numerical methods. However, these methods are based on simplifying assumptions regarding material behavior and repair conditions. In the present paper an experimental and an numerical determination of mode-I stress intensity factor (SIF), KI at the tip of an edge crack reinforced with bonded patches is undertaken by using the optical method of caustics and the finite element analysis (FEA). The experimental method of caustics is simple in its application and has successfully been used for the solution of a host of crack problems of engineering importance. The experimental results are compared with the corresponding one obtained by FEA. The program ANSYS 11 was used for the FEA. The cracked used plates were made of Lexan (PCBA) and the patches were made of Plexiglas (PMMA).