Undamaged Fibers Research Articles

Parameters’ Influence on Electrospun Polystyrene-Grubbs’ Catalyst Composite Fibers Morphology

Electrospinning represents a simple, cost-effective technique that allows the production of continuous fibers, with diameters ranging from the micrometer to the nanometer scale. Mixing particles in the polymer feed solution could result in composite fibers, with various potential applications, depending on the particle filler. The influence of electrospinning parameters on the fiber morphology must be investigated to obtain undamaged fibers without large agglomerates. This research presents polystyrene (PS)-based electrospun composite fibers, containing the first- and the second-generation Grubbs’ catalyst (G1 and G2). Loading of both catalysts was 1[Formula: see text]wt.% in the composite fibers, and the influence of different solution flow rates on fiber diameter, shape and regularity was investigated. Applied flow rates were 5, 10, 15 and 20[Formula: see text]ml/h for both composites (PS-G1 and PS-G2). Software analysis of field emission scanning electron microscopy (FESEM) images has revealed that flow rate has a higher influence on the diameter increase in PS-G1 compared to PS-G2, due to a difference in electrostatic forces and polymer-catalyst interactions. In both composites, 10[Formula: see text]ml/h was the threshold for producing smooth and undamaged fibers, further enhanced in PS-G2, where large agglomerates were observed at 20[Formula: see text]ml/h. Furthermore, in both composites, fiber diameter distribution was significantly wider at higher flow rates, which is not a desirable feature in composites. The presented results demonstrated the synergy between different parameters that influence the formation and morphology of electrospun PS-based composites and could help in the future design and processing of continuous composite fibers.

MP35-10 MECHANISMS OF FIBER-TIP DEGRADATION DURING LASER LITHOTRIPSY

You have accessJournal of UrologyCME1 Apr 2023MP35-10 MECHANISMS OF FIBER-TIP DEGRADATION DURING LASER LITHOTRIPSY Yuri Pishchalnikov, William Behnke-Parks, and Marshall Stoller Yuri PishchalnikovYuri Pishchalnikov More articles by this author , William Behnke-ParksWilliam Behnke-Parks More articles by this author , and Marshall StollerMarshall Stoller More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003269.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ureteroscopic lithotripsy breaks urinary stones using laser pulses delivered to the stone via optical fibers. Degradation of fibers reduces the efficacy of lithotripsy and varies with fiber diameter, stone composition, laser pulse energy and duration. The goal of this work was to reveal the physical mechanisms of fiber-tip damage (burnback) in water and air. METHODS: The dynamics of fiber-tip damage was studied using a high-speed camera Shimadzu HPV-X2 at a frame rate up to two million frames per second. The camera was mounted to a microscope focused on the 242-µm glass-core-diameter fiber positioned in direct contact with a target—typically, a glass slide coated with a 25±5 µm layer of hydroxyapatite (Himed, NY). Selected experiments were conducted with BegoStones and whole surgically retrieved urinary stones. Damaged fibers were cleaved to start each series of 20 pulses with flat fiber tips. Laser pulses were produced using a Lumenis VersaPulse holmium:YAG laser. Temporal profiles of infrared laser pulses and flashes of visible light were resolved using photodetectors. Cross-sectional profiles of laser-beam energy were assessed using Zap-It paper. Microscope images were used to measure the burnback length of the fiber. RESULTS: Burnback of optical fibers was associated with flashes of light (sparks) observed both in water and in air. Sparks in air could crack and fragment the fiber during single laser pulse. Twenty pulses in air produced the burnback length of 0.37 mm at 1.0 J (95% CI: 0.11–0.64 mm) and 0.14 mm at 0.6 J (95% CI: 0.10–0.18 mm), smaller than that at 1.0 J (p=0.010). In water, the fibers were damaged by sparks during the laser pulse and after the pulse during the collapse of laser-induced cavitation bubbles. Contribution of cavitation varied from insignificant to most dramatic, breaking a 1.1-mm length of the fiber in a single laser pulse. Cavitation without sparks showed no burnback with only minor damage of cladding (500 pulses, 1.0 J). Sparks were associated with an increased absorption of laser energy and were observed at laser energies typically >0.5 J and only with certain target materials near the fiber tip. Cross-sections of laser beams were larger with fibers damaged in air than that in water (p=0.007) and both were larger than that with undamaged fibers (p<0.005). CONCLUSIONS: These results suggest that the burnback degradation of optical fibers is associated mainly with laser-induced heating, ionization, and optical breakdown of target material. A better understanding of the mechanisms of fiber-tip damage will aid in development of future improvements to minimize degradation of optical fibers. Source of Funding: Research reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R43DK129104. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e473 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yuri Pishchalnikov More articles by this author William Behnke-Parks More articles by this author Marshall Stoller More articles by this author Expand All Advertisement PDF downloadLoading ...

Sedentary Behaviour Impairs Skeletal Muscle Repair Modulating the Inflammatory Response.

This study investigated whether sedentary behaviour modulates skeletal-muscle repair and tissue inflammatory response after cardiotoxin (CTX)-induced injury. Singly caged rats spent 8 weeks either as a sedentary group (SED, n = 15) or as a control group (EX, n = 15)—caged with running wheels for voluntary running. All rats had each tibial anterior muscle infused either with CTX (CTX; right muscle) or saline solution (Sham; left muscle) and were sacrificed (n = 5 per group) on the 1st, 7th, and 15th day post-injection (dpi). Histological and immunohistochemical analyses were used to calculate myotube percentage and fibrosis accretion, and quantify the number of neutrophils and M1 and M2 macrophage subtypes. The SED group showed an increased number of both neutrophils and M1 macrophages (7th and 15th dpi) compared to the EX group (p < 0.01). The EX group showed an increased number of M2 macrophages on the 1st dpi. On the 7th dpi, the SED group showed a lower myotube percentage compared to the EX group (p < 0.01) and on the 15th dpi showed only 54% of normal undamaged fibres compared to 90% from the EX group (p < 0.01). The SED group showed increased fibrosis on both the 7th and 15th dpi. Our results show that sedentary behaviour affects the inflammatory response, enhancing and prolonging the Th1 phase, and delays and impairs the SMR process.

Highly reinforced and degradable lignocellulose biocomposites by polymerization of new polyester oligomers

Unbleached wood fibers and nanofibers are environmentally friendly bio-based candidates for material production, in particular, as reinforcements in polymer matrix biocomposites due to their low density and potential as carbon sink during the materials production phase. However, producing high reinforcement content biocomposites with degradable or chemically recyclable matrices is troublesome. Here, we address this issue with a new concept for facile and scalable in-situ polymerization of polyester matrices based on functionally balanced oligomers in pre-formed lignocellulosic networks. The idea enabled us to create high reinforcement biocomposites with well-dispersed mechanically undamaged fibers or nanocellulose. These degradable biocomposites have much higher mechanical properties than analogs in the literature. Reinforcement geometry (fibers at 30 µm or fibrils at 10–1000 nm diameter) influenced the polymerization and degradation of the polyester matrix. Overall, this work opens up new pathways toward environmentally benign materials in the context of a circular bioeconomy.

Computational modeling of damage in the hierarchical microstructure of skeletal muscles

One of the skeletal muscle’s exceptional properties is its high damage tolerance in terms of its high toughness, which allows the muscle to withstand cracks of millimeter length while maintaining most of its strength (Taylor et al., 2012). In skeletal muscles, damage occurs on different hierarchical levels of the microstructure. We analyze the damage behavior on hierarchy levels 3 (muscle fiber) and 4 (fascicle) on which the most common serious muscle injuries occur. Our model captures damage initiation and rupture of activated muscle fibers resulting from eccentric contractions. We consider the interaction between muscle fibers and endomysium and investigate the influence of the components titin and endomysium on the mechanical behavior in pre-damaged fascicles. Endomysium generally transmits contractile forces. Our results show that high strains in pre-damaged fiber regions are not transferred by the endomysium and, thus, adjacent undamaged fibers are well protected. Moreover, the results show titin’s extraordinary stabilization properties of pre-damaged muscle fibers, so that macroscopic strains of fascicles are hardly reduced in case of strongly pre-damaged fibers and intact titin.

Refining gentleness – a key to bulky CTMP

Abstract Chemithermomechanical pulp (CTMP) is often used in middle layers of multiply paperboards due to its high bulk at specified strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to examine the effect of refining on bulk, taking into account conditions such as temperature, sulphonation, refining gap and refiner size. First stage CTMP made from Norway spruce (Picea abies) were produced in pilot and mill scale trials. Two new parameters, Equivalent temperature related to softness and Refining gentleness are introduced that take into account refining conditions as actual temperature, softening temperature, bound sulphonate content, refining gap and refiner diameter. The results show that bulk increases linearly with refining gentleness.

The design of special woven-preformed structures for the high-performance film cooling with undamaged fibers based on 2.5D ceramic matrix composites

A design-manufacturing integration method for the film cooling of 2.5D woven ceramic matrix composites (CMC) is proposed which can concurrently achieve film holes with undamaged fibers and improve cooling performance. Meanwhile, this study investigates the effect of different woven-preformed structures on gas-thermal-mechanical characteristics. The design-manufacturing integration method implements the collaborative design of the micro woven structure and macroscopical shaping of film holes. Firstly, the unique micro woven method can manufacture the film holes without damaged fibers which effectively guarantees the strength of CMC. Secondly, the macroscopically shaped special woven-preformed holes (SWPHs) own the special structural features related to woven structure. These special structures change the flow field and induce the counter-rotating/anticounter-rotating Vortex Pair (CVP/Anti-CVP) which effectively improves the cooling performance and controls the thermal stress. Compared with traditional drilled cylindrical hole DCH, the SWPHs’ maximum increase of averaged overall film cooling effectiveness reaches 110%. Besides, SWPHs avoid the large temperature difference between the yarn and the matrix around the drilled DCH which eventually reduces the thermal stress in the corresponding area.

Low-consistency refining of CTMP targeting high strength and bulk: effect of filling pattern and trial scale

Abstract Chemithermomechanical pulp (CTMP) is often used in central layers of multiply paperboards due to its high bulk and strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to optimize process conditions in low-consistency (LC) refining, i. e. to select or ultimately develop new optimal LC refiner filling patterns, in order to produce fibrillar fines and improve the separation of fibres from each other while preserving the natural fibre morphology as much as possible. Furthermore, the aim is to evaluate if this type of work can be done at laboratory-scale or if it is necessary to run trials in pilot- or mill-scale in order to get relevant answers. First stage CTMP made from Norway spruce (Picea abies) was LC refined in mill-, pilot- and laboratory-scale trials and with different filling patterns. The results show that an LR1 laboratory refiner can favourably be used instead of larger refiners in order to characterize CTMP with regard to tensile index and z-strength versus bulk. A fine filling pattern resulted in CTMP with higher tensile index, z-strength and energy efficiency at maintained bulk compared to a standard filling pattern.

Influence of fiber content on mechanical, tribological properties of short basalt fiber-reinforced nylon 6 and polypropylene composites

The aim of this study is to improve the physical, mechanical, and tribological properties of nylon 6 and polypropylene by reinforcing short basalt fibers (SBFs) of different weight percentages (2.5 and 5 wt%) using melt blending in a twin-screw extruder, followed by injection molding process. The control specimens without reinforcements were also prepared to compare and investigate the influence of fiber content on the properties. Density, tensile, flexural, hardness, impact strength, and tribological characterizations were performed according to ASTM standard. The results show that 5-wt% SBF-reinforced nylon composites exhibit maximum improvement in tensile, flexural, impact, hardness, and specific wear rate. Wear mechanisms were also identified using field-emission scanning electron microscope by examining the surface morphology before and after wear. The observation reveals aligned, undamaged fibers during shear mixing and injection molding. The adhesion between fiber/nylon matrix and stepped fracture in the matrix is also spotted.

Kísérleti modális elemzés alkalmazása szálerősítéses kompozitok károsodásának vizsgálatához

Detecting damage in composite materials is significantly important for the utilization of them. The paper investigates the use of the experimental part of modal analysis method to indicate damage presence in FRP specimen. The study goal is to examine the efficiency of the method to detect damage by investigating the noise, vibration and harshness (NVH) behaviour of damaged and undamaged fiber glass reinforced polymer specimen with simple geometry. A defect is generated artificially in the test specimen in order to visualize the difference in the dynamic parameters such as natural frequencies, modal damping, and mode shapes between the damaged and undamaged one. The results reveal the change of the NVH characteristics of the part during the damages leading to show the sensitivity of the experimental modal analysis for damages.

Reader response: Impaired vestibular responses in internuclear ophthalmoplegia: Association and dissociation.

I read with interest the investigation of vestibular responses in internuclear ophthalmoplegia (INO) by Choi et al.1 While the data are robust, I am concerned that the explanations do not conform with prior reports. Similar to Choi et al., my colleagues and I studied initial horizontal vestibulo-ocular reflex (VOR) in 6 patients with INO and showed reduced VOR gains for both adduction and abduction.2 Because the horizontal VOR pathway is crossed, low contralesional VOR gain is attributable to damage to fibers of passage between contralateral medial vestibular nucleus and ipsilateral abducens nucleus, without implicating deranged signals from posterior canals. Similarly, adaptation to adduction paresis refers to pulse-step mismatch of abducting saccades and cannot explain reduced contralesional horizontal VOR.3 In our study,2 horizontal VOR latencies were normal, implying integrity of direct VOR. Undamaged fibers in medial longitudinal fasciculus (MLF) or extrafascicular pathways can still initiate the VOR without delay, albeit at lower gain. Variability in horizontal VOR gain is due to the extent of MLF damage. If the same premise is applied to the vertical system, posterior canal signals in the MLF would be variably affected. Ipsilesional anterior canal excitation is preserved because signals are extrafascicular. Damage to inhibitory pathways carrying disfacilitation signals in the MLF would not contribute to preserved ipsilesional or reduced contralesional anterior canal VOR.4

Editors' note: Impaired vestibular responses in internuclear ophthalmoplegia: Association and dissociation

In “Impaired vestibular responses in internuclear ophthalmoplegia: Association and dissociation,” Choi et al. determined that the medial longitudinal fasciculus (MLF) serves as the main passage for the high-acceleration vestibulo-ocular reflex (VOR) from the contralateral posterior canal. They also concluded that the associations and dissociations of the vestibular dysfunction indicate variable combinations of damage to the vestibular fibers ascending or descending in the MLF in strokes causing isolated unilateral internuclear ophthalmoplegia (INO). Dr. Johnston raises concerns regarding these conclusions. Based on her experience, horizontal VOR latencies are normal in patients with INO, implying integrity of direct VOR. She explained that undamaged fibers in MLF or extrafascicular pathways can still initiate the VOR without delay. Dr. Kim, senior author of the study, points out, in Dr. Johnston's study, that the VOR was recorded only in the eye on the lesion side by adopting lower velocity and acceleration of head motion and did not specify the lesion extent or INO as an isolated finding. He also adds that her suggestion does not explain the preservation of the head impulse VOR for the ipsilesional anterior canal in the presence of impairments for other canals, and impaired VOR gains in the eye on the contralesional side in patients with strictly isolated unilateral INO. These findings support separate brainstem pathways for posterior and anterior canal projections pertaining to high acceleration stimuli. In “Impaired vestibular responses in internuclear ophthalmoplegia: Association and dissociation,” Choi et al. determined that the medial longitudinal fasciculus (MLF) serves as the main passage for the high-acceleration vestibulo-ocular reflex (VOR) from the contralateral posterior canal. They also concluded that the associations and dissociations of the vestibular dysfunction indicate variable combinations of damage to the vestibular fibers ascending or descending in the MLF in strokes causing isolated unilateral internuclear ophthalmoplegia (INO).

Hyperpolarization-activated channels shape temporal patterns of ectopic spontaneous discharge in C-nociceptors after peripheral nerve injury.

Neuropathic pain is thought to be mediated by aberrant impulses from sensitized primary afferents, and the temporal summation of the discharges might also influence nociceptive processing. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (Ih current) generate rhythmic activity in neurons within the central nervous system and contribute to nociceptors excitability in neuropathic pain. We searched for single fibres with ectopic spontaneous discharges from an invitro preparation in mice containing a neuroma formed in a peripheral branch of the saphenous nerve together with the undamaged branches. Both damaged (axotomized) and undamaged fibres (putative intact) developed ectopic spontaneous activity with different temporal spike trains: Clock-like, Irregular or Bursts. The Ih current blocker, ZD7288, significantly suppressed ectopic spontaneous discharges in nociceptive fibres (3/5 Aδ- and 24/31 C-units and 1 nonclassified) by 64%. Additionally, ZD7288 changed the spike patterns of 5/7 Clock-like and 3/4 Burst units to Irregular. Exogenous cAMP produced a significant ~65% increase in the ectopic firing in 5 Irregular fibres, which was restored by ZD7288. In six additional fibres (three Clock-like and three Irregular), exogenous cAMP had no further effect, but co-application with ZD7288 decreased their discharge by half. These units showed significant higher levels of discharges than the cAMP-sensitive ones. Our data suggest that HCN channels modulate ectopic spontaneous firing in C-nociceptors and shape their temporal patterns of discharge which will, ultimately, modify the nociceptive message received and processed by second-order neurons. We show an involvement of HCN channels in the modulation of ectopic spontaneous discharges from C-nociceptors. This finding exposes a mechanism of nociceptive transmission enhancement and highlights the clinical relevance of peripheral HCN blockade for spontaneous pain relief during neuropathy.

Effect of channel cracks on fiber fracture in one-component material with unidirectional fibrous structure

One-component materials with unidirectional fibrous structure are a new class of structural materials that are mechanically similar to biological ones. These contain channel cracks (CC) and weak interfaces in the structure, which are the result of production technologies. Effect of the CC size and the shear strength of contacts between fibers were investigated in the three-dimensional analysis of the elastic and inelastic shear extensions at the interface of the cracked fiber in the bundle of undamaged fibers under tension. The fiber stacking in the bundle is hexagonal. The fiber cross-sections are regular hexagons. It is found that the energy dissipation at the interface of the cracked fiber, the stress intensity factor and the crack opening displacement for the crack in the fiber and the length of the interface with the non-zero shear stresses are determined by the product of the contact cohesive shear strength and the contact width. At the optimal cohesive shear strength of the interfaces, the channel cracks shall not prejudice to the basic strength characteristics of the material.

Effect of Fiber Surface Morphology on Water Sorption of Pre-treated Hemp Fiber Reinforced LLDPE Composites

The chemical fiber pre-processing methods have been investigated, their influence on water absorption of linear low density polyethylene composites and fiber surface were evaluated by atomic force microscopy and water exposure experiments. All used fiber pre-processing methods decrease water sorption of composite. Untreated fiber composite with undamaged fiber surface more rapidly absorbs water.

Fabrication and properties of composites utilizing reclaimed woven carbon fiber by sub-critical and supercritical water recycling

Supercritical fluid recycling has emerged as an appealing method for recycling carbon fiber reinforced plastics (CFRP). Under supercritical conditions, the high reactivity, low viscosity and high diffusivity of water greatly facilitate the efficient degradation of the polymer matrix to allow the harvesting of clean and mostly undamaged fibers. We previously reported the successful use of supercritical water recycling to recover carbon fibers from high-performance single-layer composites and possibly multi-layered composites. The fibers are reclaimed in the original woven architecture, which is beneficial for direct use for reclaimed-fiber composites. In this study, the fabrication of reclaimed-fiber composites (RFC) was investigated using fibers recycled from aerospace-grade IM7/8552 (Hexcel) 12-layer composites. Two fabrication methods – hand lay-up and vacuum infusion – were attempted. The recycled matrix materials were also combined with fresh resin and cured. The reclaimed-fiber composites exhibited 80–95% of flexural strength of virgin carbon fiber composites. This paper also discusses the manufacturing issues associated with the reuse of reclaimed materials.

The Effectiveness of Operational Modal Analysis (OMA) for Detecting Saw Cut Damage in Fiberglass Reinforced Epoxy

This study attempts to apply vibration based damage detection method specifically operational modal analysis (OMA) on fiberglass reinforced epoxy plate. OMA is used on undamaged fiber glass reinforced epoxy plate to extract the modal parameters and after which the procedure is extended to saw cut damage fiberglass reinforced epoxy plate. Both healthy and damaged composite material are tested for different boundary conditions i.e. free-free on 4 edges, 1 edge clamped, 2 edges clamped, 3 edges clamped and 4 edges clamped condition. Then result of frequency from OMA was compared analytically with finite element method. Based on the results, it shows that a high deviation between OMA and finite element method can be observed. Result of frequency from OMA was then compared with Experimental Modal Analysis (EMA) to validate the effectiveness of OMA method. It is shown that results obtained from OMA are in good correlation with results obtained from EMA.

Locomotor recovery after spinal cord hemisection/contusion injures in bonnet monkeys: Footprint testing—a minireview

Spinal cord injuries usually produce loss or impairment of sensory, motor and reflex function below the level of damage. In the absence of functional regeneration or manipulations that promote regeneration, spontaneous improvements in motor functions occur due to the activation of multiple compensatory mechanisms in animals and humans following the partial spinal cord injury. Many studies were performed on quantitative evaluation of locomotor recovery after induced spinal cord injury in animals using behavioral tests and scoring techniques. Although few studies on rodents have led to clinical trials, it would appear imperative to use nonhuman primates such as macaque monkeys in order to relate the research outcomes to recovery of functions in humans. In this review, we will discuss some of our research evidences concerning the degree of spontaneous recovery in bipedal locomotor functions of bonnet monkeys that underwent spinal cord hemisection/contusion lesions. To our knowledge, this is the first report to discuss on the extent of spontaneous recovery in bipedal locomotion of macaque monkeys through the application of footprint analyzing technique. In addition, the results obtained were compared with the published data on recovery of quadrupedal locomotion of spinally injured rodents. We propose that the mechanisms underlying spontaneous recovery of functions in spinal cord lesioned monkeys may be correlated to the mature function of spinal pattern generator for locomotion under the impact of residual descending and afferent connections. Moreover, based on analysis of motor functions observed in locomotion in these subjected monkeys, we understand that spinal automatism and development of responses by afferent stimuli from outside the cord could possibly contribute to recovery of paralyzed hindlimbs. This report also emphasizes the functional contribution of progressive strengthening of undamaged nerve fibers through a collateral sprouts/synaptic plasticity formed in partially lesioned cord of monkeys.

Fracture and Damage Characterization of Natural Fiber Composites

This paper reports the microscopic fracture behavior of natural fiber-reinforced green composites. The acoustic emission (AE) method of nondestructive and real-time testing was applied to detect small-scale energy release phenomena during tensile deformation of the green composites. The unidirectional abaca fiber was embedded in a starch-based biodegradable resin matrix. Two kinds of pre-damaged abaca fibers as well as as-received (i.e. undamaged) fiber were used to examine the effect of the pre-damaged abaca fiber on the overall fracture behavior of the unidirectional green composites. In the case of the green composites reinforced with as-received abaca fiber, both of the tensile strength and fracture strain were relatively high. In the case of the green composites reinforced with pre-damaged abaca fiber, however, showed relatively smaller tensile strength and fracture strain. In addition, a wide range of amplitude AE events were measured during the tensile deformation. This tendency was enhanced in the composites reinforced with heavily damaged abaca fiber. The experimental results showed that the AE activity in the early deformation stage was associated with such the microscopic fracture of pre-damaged abaca fibers.

Effect of FRP Pipe Scaling on its Adhesive Bonding Strength

Polymer-based materials are emerging as a potential substitute for metallic structures in the oil and gas industry. In this context, fiber-reinforced polymer (FRP) piping is one promising application. An important area of the research pertaining to FRP piping is the connection of pipe sections. Challenges associated with the joining of FRP tubular sections are often considerable, which limits more widespread industrial application. Adhesive bonding is emerging as a promising technique to join tubular FRP structures. The ability to maintain undamaged fiber architecture is a major advantage of adhesive bonding technology. In the present study a strength-of-materials as well as fracture mechanics approach was employed in conjunction with the finite element method to investigate the scaling effects on adhesively bonded tubular sections. It was found that the scaling effects in joined FRP pipe may be significant. For certain composite material configurations the analysis indicated a shift of the region of failure from the pipe structure to pure adhesive (cohesive) failure with increasing pipe diameter.