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Wyniki wyszukiwania dla: failure
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The impact of surface slope and calculation resolution on the fractal dimension for fractures of steels after bending-torsion fatigue
PublikacjaThe article presents the results of the fractal dimension measurements on the fatigue fracture surfaces of 10HNAP and S355J2 steels specimens after combined bending-torsion fatigue. For smooth and ring-notched specimens, three loading conditions were analyzed: (1) bending; (2) bending-torsion; and (3) torsion fatigue. Post-failure surface topography measurements were carried out on the entire fracture surfaces using an optical...
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3D X-ray Micro-CT Analysis of Rebar Corrosion in Reinforced Concrete Subjected to a Chloride-Induced Environment
PublikacjaThe paper presents experimental investigations of the concrete cover protective ability to coun-teract rebar corrosion in reinforced concrete cubes. To study and quantify the consequences of corrosion a reinforced concrete sample was subjected to chloride-induced environment in order to get corroded and combined with un-corroded sample. Chloride-accelerated technique can in-duce a high degree of corrosion within at a controlled...
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Accurate and continuous adhesive fracture energy determination using an instrumented wedge test
PublikacjaThe wedge test and the related double cantilever beam test are practical methods of assessing structural adhesive fracture energy. In the former, and to a lesser extent the latter, a recognised problem is the difficulty of following the length of the growing crack, required to calculate fracture energy with any accuracy. We present a novel method of measurement of crack length that has the advantages of being accurate and allowing...
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Mathematical modelling of implant in an operated hernia for estimation of the repair persistence
PublikacjaThis paper presents mathematical modelling of an implanted surgical mesh used in the repair process of the abdominal hernia. The synthetic implant is simulated by a membrane structure. The author provides a material modelling of the implant based on the dense net model appropriate for technical fabrics. The accuracy of the proposed solution is evaluated by comparing the simulations of the dynamic behaviour of the system with the...
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Disciplines and measures of information resilience
PublikacjaCommunication networks have become a fundamental part of many critical infrastructures, playing an important role in information delivery in various failure scenarios triggered e.g., by forces of nature (including earthquakes, tornados, fires, etc.), technology-related disasters (for instance due to power blackout), or malicious human activities. A number of recovery schemes have been defined in the context of network resilience...
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Theoretical examination of the fracture behavior of BC3 polycrystalline nanosheets: Effect of crack size and temperature
Publikacja2D carbon graphene nanostructures are elements of advanced materials and systems. This theoretical survey provides explanation to the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (denoted as MC- and PCBC3NS, respectively) as a function of temperature and the type of crack defects. The mechanical performance of PCBC3NS at elevated temperatures was monitored varying the number of grain boundaries (the...
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eFRADIR: An Enhanced FRAmework for DIsaster Resilience
PublikacjaThis paper focuses on how to increase the availability of a backbone network with minimal cost. In particular, the new framework focuses on resilience against natural disasters and is an evolution of the FRADIR/FRADIR-II framework. It targets three different directions, namely: network planning, failure modeling, and survivable routing. The steady state network planning is tackled by upgrading a sub-network (a set of links termed...
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Impact response of two-layered grouted aggregate fibrous concretecomposite under falling mass impact
PublikacjaTwo-layered Grouted Aggregates Fibrous Concrete Composite (TGAFCC) is a new category concrete which became popular recently and attracted the attention of researchers globally. Recent studies indicated that TGAFCC has notable improvement in mechanical properties, which has been sufficiently documented. However, the impact behaviour of TGAFCC when combined with Glass Fibre Mesh (GFM) and Textile Fibre Mesh (TFM) is still unexplored....
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RESEARCH OF PARTIAL DISCHARGE IN THE LABORATORY CONSTRUCTE
PublikacjaNowadays in the Czech Republic begins implementation of new types of leadership system with insulated conductors nowadays. This system is used because of the use of conductors in difficulties to reach terrains and lower failure rate. The finding of specific faults is problem, because today's digital protection are not able to find it.
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Instantaneous impedance monitoring of synergistic effect between cavitation erosion and corrosion processes
PublikacjaThe most common method of determination of cavitation erosion resistance as well as the magnitude of erosion-corrosion synergistic interaction is based on the weight loss measurements. Nondestructive characterization of installations elements is in most cases impossible to perform. Also, such a measurement does not include local types of failure or alteration of operating conditions. There is an urge to elaborate a method for monitoring...
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Maximum forces in tendon connections for an anchor with a pin in the full sample experiment
Dane BadawczeThe main objective of the all study was to assess the load capacity of a new implant device for knotless tendon anastomosis. During this series of experiments the load capacity of the anchoring element with a pin (see figure 1) was examined. Tendons from fresh swine legs (commercially available) served as the biological material. All samples were subjected...
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The risk of corporate bankruptcy - the conceptual model
PublikacjaThis article concerns the assessment of different types of risks influencing the corporate bankruptcy risk. The author has developed conceptual model that explains the causes and the trajectories of the collapse of enterprises. In the analyses such factors as demographic, financial, market, political and operational factors influencing the risk of failure were taken into account.
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Ocena technologii tulei rozprężnej z wykorzystaniem metody FMEA.
PublikacjaPrzedstawiono wykorzystanie metody FMEA (Failure Mode and Effect Analysis) do analizy procesu technologicznego tulei rozprężnej jako elementu roboczego docieraka do obróbki maszynowo-ręcznej otworów walcowych. W ocenie technologii uwzględniono symulowaną zmienność liczb priorytetowych, występowania, znaczenia i wykrywalności.
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Experimental and numerical study on deformed steel columns subjected to impact load during earthquakes
PublikacjaThe soft-storey failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an upper soft storey of a structure results in large impact load acting on the lower floors and if the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of the whole building. The aim of the present paper is to investigate the dynamic behaviour...
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Tensile curve of E grade steel for shipbuilding
Dane BadawczeIn the shipbuilding industry, the risk of brittle fractures developing in constructions is limited by employing certified materials of specific impact strength, determined using the Charpy method (for a given design temperature) and by exercising control over the welding processes (technology qualification, supervision of production, tests of non-destructive...
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Maximum forces in tendon connections for an anchor without pin in the single-side sample experiment
Dane BadawczeThe main objective of the all study was to assess the load capacity of a new implant device for knotless tendon anastomosis. During this series of experiments the load capacity of the anchoring element without a pin (see figure 1) was examined. Tendons from fresh swine legs (commercially available) served as the biological material. All samples were...
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Maximum forces in tendon connections for an anchor with pin in the single-side sample experiment
Dane BadawczeThe main objective of the all study was to assess the load capacity of a new implant device for knotless tendon anastomosis. During this series of experiments the load capacity of the anchoring element with a pin (see figure 1) was examined. Tendons from fresh swine legs (commercially available) served as the biological material. All samples were subjected...
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Maximum forces in tendon connections for the Kessler suture in the single-side sample experiment
Dane BadawczeThe main objective of the all study was to assess the load capacity of a new implant device for knotless tendon anastomosis. During this series of experiments the load capacity of the traditional two-strand Kessler sutures (3-0 sutures) was examined. Tendons from fresh swine legs (commercially available) served as the biological material. All samples...
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Simple Computational Methods in Predicting Limit Load of High-Strength Cold-Formed Sections due to Local Buckling: A Case Study
PublikacjaCold-formed thin-walled sections are prone to local buckling caused by residual stresses, geometrical imperfections and inconsistency of material properties. We present a real case of buckling failure and conduct a numerical and experimental study aimed to identify methods capable of predicting such failures. It is important because designers of structures are getting more FEA-oriented and tend to avoid lengthy procedures of cold-formed...
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Monte Carlo simulations of the fracture resistance of an asphalt pavement layer
PublikacjaThe purpose of the proposed numerical model is to analyze the cracking of the wearing course in a pavement overlay, assuming a pre-existing crack that passes through the binding layer and base. The computations employed the author's simulation-based Monte Carlo material model, which describes the failure process of a Semi-Circular Bend (SCB) specimen during standard laboratory testing of asphalt concrete. A key feature of this...
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Degradation of stiffness of building columns exposed to bending and impact load during ground motions
PublikacjaThe safety of civil engineering structures under external loads, including ground motions, is one of the issues related to the idea of sustainable society. The earthquake-induced soft-storey failure is a typical type of damage observed in buildings due to seismic excitation. The failure of an intermediate soft storey of a structure results in large vertical impact loading acting on the lower floors due to the fall of the upper...
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Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
PublikacjaIn this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue...
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Characterization of corrosion in reinforced concrete beams using destructive and non-destructive tests
PublikacjaThe paper presents both non-destructive and destructive experimental tests on steel-reinforced concrete beams subjected to electrochemical corrosion. To examine the condition and behavior of the specimens, destructive tests were carried out, i.e., a three-point bending together with a modulated ultrasonic wave test. In addition, a series of non-destructive experiments were conducted, such as the potential measurement method, low-frequency...
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MARSTRUCT benchmark study on nonlinear FE simulation of an experiment of an indenter impact with a ship side-shell structure
PublikacjaThis paper presents a benchmark study on collision simulations that was initiated by the MARSTRUCT Virtual Institute. The objective was to compare assumptions, finite element models, modelling techniques and experiences between established researchers within the field. Fifteen research groups world-wide participated in the study. An experiment involving a rigid indenter penetrating a ship-like side structure was used as the case...
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Identification of defected sensors in an array of amperometric gas sensors
PublikacjaPurpose Amperometric gas sensors are commonly used in air quality monitoring in long-term measurements. Baseline shift of sensor responses and power failure may occur over time, which is an obstacle for reliable operation of the entire system. The purpose of this study is to check the possibility of using PCA method to detect defected samples, identify faulty sensor and correct the responses of the sensor identified as faulty. Design/methodology/approach In...
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Emergency condition of the ceramic facade of a residential building
PublikacjaThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Emergency condition of the ceramic facade of a residential building
PublikacjaThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Wybrane metody przydatne w analizie niezawodności i bezpieczeństwa funkcjonalnego systemów technicznych.
PublikacjaPrzedstawiono wybrane metody przydatne w analizie niezawodności i bezpieczeństwa funkcjonalnego systemów technicznych takie jak: metoda FMECA (failure mode, effect and criticality analysis, FTA (fault tree analysis, RBD (reliability block diagram) RCM (reliability centered maintenance, LCC (life cycle cost) i PMO (preventive maintenance optimising.
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Discrete Modelling of Micro-structural Phenomena in Granular Shear Zones
PublikacjaThe micro-structure evolution in shear zones in cohesionless sand for quasi-static problems was analyzed with a discrete element method (DEM). The passive sand failure for a very rought retaining wall undergoing horizontal translation towards the sand backfill was discussed. To simulate the behaviour of sand, the spherical discrete element model was used with elements in the form of rigid spheres with contacts moments.
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Resonant Conditions in a Node with an SVC Compensator
PublikacjaThe primary purpose of installing static shunt compensators in power grids is to improve the voltage conditions. Additional reactive power sources increase the system’s voltage stability and enable faster system recovery after a voltage failure. This paper presents the impact of an SVC device’s structure and settings on impedance change in the supply system, and hence on the frequencies at which resonance phenomena can develop.
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Impact Behaviour of Glass Fribre /Epoxy Composites with Nano-Enhanced Resin after Water Exposure
PublikacjaImpact behaviour of glass fibre /epoxy composites with nano- SiO2 modified resin was studied in terms of low velocity impact after water exposure. Nanocomposites with 1%, 2%, 3% 5% 7% nano-SiO2 (Nanopox- Evonic) were investigated. Peak impact load and impact damage area as a function of nanoparticle contents were compared for dry specimens and for samples exposed to water (0.7 %wt. 1.7% water absorbed) at 1J, 2J 3J impact energies....
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Cyclic deformation and fracture behaviour of additive manufactured maraging steel under variable-amplitude loading
PublikacjaThe cyclic deformation and fracture behaviour of 18Ni300 maraging steel produced by laser beam powder bed fusion is studied under variable-amplitude loading. The tests were conducted under fully-reversed strain-controlled conditions with a loading sequence comprising three ascending cycles and three descending cycles repeated sequentially until failure. After the tests, fracture surfaces were examined using height and volume surface...
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The effect of fishing basin construction on the behaviour of a footbrdge over the port channel
PublikacjaThe paper analyses possible causes of failure of the rotating footbridge over the Ustka port channel. In July, 2015, strange behaviour of this object was observed in the form of excessive vibrations of bridge platform suspension rods, with the accompanying acoustic effects. A preliminary geotechnical analysis has revealed that this destructive effect was caused by the nearby construction works, namely construction of a fishing...
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STOMACH, Stomach, NOS - Female, 55 - Tissue image [9140730014145121]
Dane BadawczeThis is the histopathological image of STOMACH tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Corrugated Sheeting as a Member of a Shear Panel Under Repeated Load—Experimental Test
PublikacjaIn stressed-skin design, the cladding stiffening effect on structures is taken into account. However, the “traditional” design is more usual, wherein this effect is neglected. Even if the diaphragm actions are not regarded, in particular cases such as big sheds (and others), the parasitic (unwanted) stressed-skin action may occur with the result of leakage or even failure. The structures of this kind have already been built. Thus,...
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Investigations of size effect in concrete at aggregate level - experiments and calculations results using discrete element method
PublikacjaSize effect is a fundamental phenomenon in concrete. It is characterised by decreasing strength and increasing brittleness of concrete with increasing size. The thesis includes experimental and theoretical elements. The main goal of the thesis were investigations of a size effect at the aggregate level by taking fracture into account with the discrete element method (DEM) for various failure modes. Comprehensive experiments on...
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Monitoring of a historic sacral building on an example Basilica St. Nicholas in Gdańsk
Publikacjahe paper describes the case of monitoring the technical condition of a historic sacral building after a failure and during renovation works. In order to monitor the condition of the building, safely conduct diagnostic work, identify the causes of failures andsafely carry out renovation works, a detailed Facility Monitoring Program has been developed, which has been implemented, is operational and is a source of valuable data used...
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Zarządzanie wiedzą w małych przedsiębiorstwach oferujących wiedzochłonne usługi biznesowe
PublikacjaCelem artykułu jest przedstawienie praktyk zarządzania wiedzą oraz czynników wpływających na sukces, bądź porażkę w ich wdrażaniu na podstawie badania jakościowego przeprowadzonego w trzech firmach działających na terenie województwa pomorskiego. Firmy te należą do sektora małych i średnich przedsiębiorstw oraz oferują wiedzochłonne usługi biznesowe (knowledge-intensive business services – KIBS). W artykule podjęto próbę odpowiedzi...
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Teledetekcyjne badanie konstrukcyjnych elementów żelbetowych z użyciem naziemnego skaningu laserowego
PublikacjaWspółczesna technologia naziemnego skaningu laserowego (TLS) z użyciem skanerów geodezyjnych o zasięgu większym niż 50 metrów pozwala na pomiar geometrii elementów konstrukcyjnych z dokładnością bliską 1 mm. Autorzy, w oparciu o badania laboratoryjne i doświadczenia własne, prezentują rozwiązanie pozwalające na wstępną ocenę belek żelbetowych jako podstawowych elementów konstrukcyjnych budowli typu mosty, wiadukty, budynki wielkopowierzchniowe. Przedmiotem...
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Hertzian Crack Propagation in Ceramic Rolling Elements
PublikacjaThe properties of ceramics are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such crack are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack...
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Nonlinear FEM analysis of irregular shells composed of fiber metal laminates
PublikacjaThe paper deals with the analysis of failure initiation in shells made of Fiber Metal Laminates (FML). The elas-tic material law for orthotropic lamina is stated accounting for asymmetric in-plane stress and strain measures. The asymmetry results from the employed general nonlinear 6-field shell theory where the generalized dis-placements involve the translation and the proper rotation field. The novelty of the presented results...
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Awarie mostu Cłowego w Szczecinie
PublikacjaW artykule przedstawiono historię budowy i eksploatacji mostu Cłowego w Szczecinie. W ciągu 56 lat eksploatacji obiektu wykonano wiele ekspertyz, napraw i remontów. Ostatecznie most został zamknięty z powodu awarii stalowych kabli sprężenia zewnętrznego. Przedstawiono główne przyczyny degradacji obiektu i awarii. Opisano również obliczenia statyczne i wytrzymałościowe wykonane do koncepcji rozbiórki przęseł mostu.
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Most Cłowy w Szczecinie. Historia i przyszłość
PublikacjaW referacie przedstawiono historię budowy i cykl życia kablobetonu mostu Cłowego w Szczecinie. W trakcie 56-letniego życia obiektu kilka prac eksperckich i naprawy zostało wykonanych. Ostatecznie most został zamknięty po poważnej awarii strukturalnej zewnętrznego kabla sprężenia. Wyjaśniono główne przyczyny degradacji oraz przedstawiono koncepcję projektową remontu.
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BLADDER, Bladder wall, NOS - Female, 55 - Tissue image [9140730014141581]
Dane BadawczeThis is the histopathological image of BLADDER tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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SMALL INTESTINE, Jejunum - Female, 55 - Tissue image [914073001414651]
Dane BadawczeThis is the histopathological image of SMALL INTESTINE tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Scanning electron microscopy studies of the weld decay on SS 304 of water supply pipeline
Dane BadawczeThis dataset contains micrographs made with scanning electron microscope (SEM) Hitachi S-3400N, of the weld decay for water supply system pipelines made of AISI 304 stainless steel. Within the dataset one can see the different corrosion mechanisms. The micrographs were made after the Strauss test (excluding pictures labeled as pits_in_HAZ, done without...
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Accuracy improvement of the prestressed concrete structures precise geometry assessment by use of bubble micro-sampling algorithm
PublikacjaPrestressed concrete structures are well-known technology for a vast period, but nevertheless, this very technology is a leading solution, currently used in construction industry. Prestressed concrete structures have a huge advantage over conventional methods because it uses the properties of concrete in a very efficient way. The main idea behind this technology is to introduce into the cross-section of the structure, the internal...
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Behaviour of deformed steel columns exposed to impact load during earthquakes - experimental study
PublikacjaIt has been observed during major earthquakes that the so called soft-storey failure of an upper floor of a structure results in large impact load acting on structural members of the lower storeys. It may further lead to progressive collapse of the whole structure substantially intensifying human and material losses. The aim of this paper is to investigate experimentally the behaviour of horizontally deformed columns (deformation...
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Effect of bending-torsion on fracture and fatigue life for 18Ni300 steel specimens produced by SLM
PublikacjaIn this study, different fracture surfaces caused by fatigue failure were generated from 18Ni300 steel produced by selective laser melting (SLM). Hollow round bars with a transverse hole were tested under bending-torsion to investigate the crack initiation mechanisms and fatigue life. Next, the post-failure fracture surfaces were examined by optical profilometer and scanning electron microscope. The focus is placed on the relationship...
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Biomechanics of the front abdominal wall as a potential factorleading to recurrence with laparoscopic ventral hernia repair
PublikacjaThis study investigated the front abdominal wallto describe its elasticity in vivo and searched for elongationsthat possibly stretched an implanted mesh, therebycausing fixation failure and subsequent recurrence.To measure front abdominal wall elongations, amodel of fascia movements was created. Eight healthyvolunteers were measured during exercise to determine theextent of elongations in their front abdominal wall. Videoswere...