Cyclic Bending Tests Research Articles

Strain Distribution and Its Relationship to Crack Initiation and Propagation Behavior During Cyclic Bending Test on Commercial SUS301 Sheet

Strain Distribution and Its Relationship to Crack Initiation and Propagation Behavior During Cyclic Bending Test on Commercial SUS301 Sheet

Combustion-assisted low-temperature ZrO2/SnO2 films for high-performance flexible thin film transistors

We developed high-performance flexible oxide thin-film transistors (TFTs) using SnO2 semiconductor and high-k ZrO2 dielectric, both formed through combustion-assisted sol-gel processes. This method involves the exothermic reaction of fuels and oxidizers to produce high-quality oxide films without extensive external heating. The combustion ZrO2 films were revealed to have an amorphous structure with a higher proportion of oxygen corresponding to the oxide network, which contributes to the low leakage current and frequency-independent dielectric properties. The ZrO2/SnO2 TFTs fabricated on flexible substrates using combustion synthesis exhibited excellent electrical characteristics, including a field-effect mobility of 26.16 cm2/Vs, a subthreshold swing of 0.125 V/dec, and an on/off current ratio of 1.13 × 106 at a low operating voltage of 3 V. Furthermore, we demonstrated flexible ZrO2/SnO2 TFTs with robust mechanical stability, capable of withstanding 5000 cycles of bending tests at a bending radius of 2.5 mm, achieved by scaling down the device dimensions.

Correlation Effect on Different Temperature-Humidity Range of Highly Thermal GNP/AG/ SA Conductive Ink

The study evaluates how the resistivity and properties of the material change in response to environmental factors such as temperature and humidity, and how these changes impact its performance in various applications. In order to develop a highly thermal graphene hybridization conductive ink, a new formulation of conductive ink was formulated using graphene nanoplatelet (GNP), silver flake (Ag), and silver acetate (SA) as conductive fillers mixed with organic solvents. The batch of chemicals was converted into a powder by undergoing sonication and stirring to create a powdery state. The powder was then treated with organic solvents, specifically 1-butanol and terpineol, and mixed using a thinky mixer to form a paste. The GNP/Ag/SA hybrid conductive ink paste was then printed on copper substrates using a mesh stencil and was cured at 250°C for 1 hour. Cyclic testing had been conducted using a cyclic bending test machine and a cyclic torsion test machine in a heat chamber with different temperature-humidity. The new formulation then was characterized base on the electrical and mechanical behaviour. After the torsion and bending tests, the GNP/Ag/SA hybrid conductive ink formulation reliability was evaluated. GNP/Ag/SA hybrid conductive ink room temperature baseline and GNP/Ag/SA hybrid conductive ink after given different temperature-humidity were compared in terms of electrical and mechanical properties. Both cyclic bending and torsion testing results showed an increasing value of resistance and resistivity with every progress of bending and torsion cycle, which displays a clear trend. The results indicate that the average resistance values at all sample points either stay constant or decrease with the increasing temperature. This observation suggests that the ink's electrical conductivity remains rather stable as the temperature increases. Thus, even with rising temperatures, the ink's electrical conductivity remains stable, indicating the ink's capacity to preserve its integrity and structural qualities within a defined temperature range. Future research should focus on improving the adhesion, stability and reliability of stretchable conductive inks under various temperature and humidity conditions.

Monitoring of relative magnetic permeability variation during cyclic bending testing of austenitic steel grade 10Kh18n10t samples

Cyclic bending testing of austenitic chromium-nickel steel grade 10Kh18N10T samples was carried out. Evalution of relative magnetic permeability showed its noticeable increase when the samples became fractured. This increase is related to deformation martensite appearance. Additional experiment showed, that deformation martensite formation starts before the actual destruction of the sample.

Comparison of Bending Stiffness between String of Pearls Plate-Bone Substitute Constructs with and without Bending Tees in a Fracture Gap Model

Abstract Objective The aim of this study was to compare the bending properties of String of Pearls plate-bone substitute constructs with and without bending tees in the nodes over a simulated fracture gap. It is hypothesized that the constructs with tees will have higher bending stiffness. Study Design Acetal polymer tubes and 12-hole, 3.5-mm String of Pearls plates were used to create plate-bone substitute constructs simulating stabilization in a bridging fashion over a 45-mm gap. Twenty-four constructs were made with 12 containing tees in the nodes over the fracture gap. Single-cycle load-to-failure 4-point bending was performed in mediolateral and craniocaudal planes. Bending stiffness was compared with a t-test (p < 0.05). Results All plate-bone substitute constructs had a permanent loss of structural integrity via plastic deformation of the plate. The bending stiffness (mean ± standard deviation) of the craniocaudal group was 59.11 ± 1.98 N/mm with tees and 59.25 ± 1.69 N/mm without tees (p = 0.88). In the mediolateral group, the bending stiffness was 43.17 ± 0.75 N/mm with tees and 41.09 ± 0.91 N/mm without tees (p = 0.0042). Conclusion In 4-point bending, the plate-bone substitute constructs with tees had equivalent bending stiffness in the craniocaudal plane and increased bending stiffness in the mediolateral plane. However, with a small absolute difference in values, the clinical significance is unclear. Future studies for cyclic bending, torsional, and axial compression tests should be performed to further investigate the value of tees in the nodes over a comminuted or gap fracture repaired in a bridging fashion.

Failure analyses for plate monotonic/cyclic and elbow out-of-plane cyclic loading tests using the Gurson–Tvergaard–Needleman model

In this study, an analytical approach is proposed to simulate the failure behavior of a thinned-wall pipe elbow subjected to internal pressure and out-of-plane cyclic bending loads. This approach incorporates the Gurson–Tvergaard–Needleman model, whose parameters were determined by the plate monotonic tensile test and finite element analyses. The applicability of this analytical approach for low-cycle fatigue failure was confirmed through experiments and simulations. The analytical results captured the failure behavior of the pipe elbow during the out-of-plane cyclic bending test. This finding suggests that the analytical approach can be used for nonlinear deformation evaluation and multiaxial low-cycle fatigue assessment of piping systems.

Comprehensive Study of Mechanical, Electrical and Biological Properties of Conductive Polymer Composites for Medical Applications through Additive Manufacturing.

Conductive polymer composites are commonly present in flexible electrodes for neural interfaces, implantable sensors, and aerospace applications. Fused filament fabrication (FFF) is a widely used additive manufacturing technology, where conductive filaments frequently contain carbon-based fillers. In this study, the static and dynamic mechanical properties and the electrical properties (resistance, signal transmission, resistance measurements during cyclic tensile, bending and temperature tests) were investigated for polylactic acid (PLA)-based, acrylonitrile butadiene styrene (ABS)-based, thermoplastic polyurethane (TPU)-based, and polyamide (PA)-based conductive filaments with carbon-based additives. Scanning electron microscopy (SEM) was implemented to evaluate the results. Cytotoxicity measurements were performed. The conductive ABS specimens have a high gauge factor between 0.2% and 1.0% strain. All tested materials, except the PA-based conductive composite, are suitable for low-voltage applications such as 3D-printed EEG and EMG sensors. ABS-based and TPU-based conductive composites are promising raw materials suitable for temperature measuring and medical applications.

Electrospun biomass polyethylene furanoate nonwoven substrates for flexible thermoelectric generators

Polyethylene furanoate (PEF) stands out as a highly promising biopolymer, characterized by its lower melting point and higher flexibility than those of polyethylene terephthalate (PET). Moreover, the enhanced functionality of PEF broadens its potential applications across various domains. Herein, the synergistic integration of PEF with a polymer thermoelectric layer is explored via the formulation of advanced environmentally sustainable materials for prospective utilization in flexible thermoelectric generators for the emerging field of green energy. The fabrication process involves the creation of PEF nonwoven via the electrospinning technique, thereby endowing the PEF with considerable stretchability. Concurrently, the polymer thermoelectric layer is developed by blending dimethyl sulfoxide (DMSO) and d-sorbitol in a poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) solution, followed by drop-casting PEDOT:PSS onto glass substrates. Subsequently, free-standing PEDOT:PSS films are transposed onto PEF nonwoven substrates with a power factor of 17.84 μW m⁻1 K⁻2 and an elongation of 24 % at breaking point. The intimate compatibility between the PEDOT:PSS film and PEF nonwoven substrate is demonstrated by the cyclic bending test results, wherein over 90 % of the original conductivity is maintained after 1000 cycles, thereby highlighting the potential of the developed device as a thermoelectric generator. Finally, a 12-leg thermoelectric generator is fabricated, yielding an output voltage of 3.63 mV and an output power of 34.52 nW under a temperature gradient of 32.3 K.

Development of a cyclic semi-circular bending test protocol to characterize fatigue cracking of asphalt mixture at intermediate temperature

The Semi-Circular Bending (SCB) test has been traditionally conducted in a monotonic loading and displacement-controlled mode at intermediate temperature to assess the fatigue crack resistance of asphalt mixtures. However, fatigue damage is essentially deterioration in material integrity as a result of repeated loading. The SCB monotonic loading does not realistically reflect the traffic loading repetition. This may have limitation on mechanism of the fatigue cracking in asphalt mixture. This study aims to develop a cyclic SCB test protocol to characterize the fatigue cracking of asphalt mixtures. Digital Image Correlation (DIC) was utilized to identify crack length associated with the number of loading cycles applied. A full factorial design was conducted for the optimization of testing parameters of the cyclic SCB test, including three levels of notch depth and loading frequency. Two indicators including the number of cycles to failure and Paris’ Law coefficients were used to characterize the fatigue cracking resistance of asphalt mixture. The proposed test protocol of cyclic SCB was validated by three asphalt mixtures of good, medium, and poor cracking performance. The critical strain energy release rate Jc of three mixtures is also measured by the monotonic SCB test for studying the relationship between Jc and Paris’ Law coefficients. The results indicate that Paris’ Law coefficients have relatively low variance compared to the number of cycles to failure and are independent of notch depth and loading frequency. The optimal testing parameter combination of 25 mm notch depth and 10 Hz loading frequency was recommended in perspective of test variance and test practicability. The Paris Law coefficient n ranking was consistent with the one of fatigue cracking resistance of asphalt mixtures evaluated.

Anisotropic Superhydrophobic Properties Replicated from Leek Leaves.

A bio-inspired approach to fabricate robust superhydrophobic (SHB) surfaces with anisotropic properties replicated from a leek leaf is presented. The polydimethylsiloxane (PDMS) replica surfaces exhibit anisotropic wetting, anti-icing, and light scattering properties due to microgrooves replicated from leek leaves. Superhydrophobicity is achieved by a novel modified candle soot (CS) coating that mimics leek's epicuticular wax. The resulting surfaces show a contact angle (CA) difference of ≈30° in the directions perpendicular and parallel to the grooves, which is similar to the anisotropic properties of the original leek leaf. The coated replica is durable, withstanding cyclic bending tests (up to 10 000 cycles) and mechanical sand abrasion (up to 60g of sand). The coated replica shows low ice adhesion (10kPa) after the first cycle; and then, increases to ≈70kPa after ten icing-shearing cycles; while, anisotropy in ice adhesion becomes more evident with more cycles. In addition, the candle soot-coated positive replica (CS-coated PR) demonstrates a transmittance of ≈73% and a haze of ≈65% at the wavelength of 550nm. The results show that the properties depend on the replicated surface features of the leek leaf, which means that the leek leaf appears to be a highly useful template for bioinspired surfaces.

Self-Assembled TiN-Metal Nanocomposites Integrated on Flexible Mica Substrates towards Flexible Devices.

The integration of nanocomposite thin films with combined multifunctionalities on flexible substrates is desired for flexible device design and applications. For example, combined plasmonic and magnetic properties could lead to unique optical switchable magnetic devices and sensors. In this work, a multiphase TiN-Au-Ni nanocomposite system with core-shell-like Au-Ni nanopillars embedded in a TiN matrix has been demonstrated on flexible mica substrates. The three-phase nanocomposite film has been compared with its single metal nanocomposite counterparts, i.e., TiN-Au and TiN-Ni. Magnetic measurement results suggest that both TiN-Au-Ni/mica and TiN-Ni/mica present room-temperature ferromagnetic property. Tunable plasmonic property has been achieved by varying the metallic component of the nanocomposite films. The cyclic bending test was performed to verify the property reliability of the flexible nanocomposite thin films upon bending. This work opens a new path for integrating complex nitride-based nanocomposite designs on mica towards multifunctional flexible nanodevice applications.

Polystyrene-polyisoprene-polystyrene coated Fe3C–C/MXene composite film based flexible, and multifunctional patch for electromagnetic interference shielding and joule heating

Portable and wearable electronics demand flexible, multifunctional films with electromagnetic interference (EMI) shielding and thtaermal management capabilities. However, the preparation of flexible films with suitable performance is still a challenge. Here, we constructed the flexible, stretchable, and multifunctional patch with a multistage structure composed of Fe3C–C (FC) fibrous film, MXene, and polystyrene-polyisoprene-polystyrene (SIS), which exhibited outstanding EMI shielding effectiveness total (SET) of 56 dB. Due to the package of the SIS layer, the EMI SE of the as-prepared patch remains almost unchanged after 3000 cycles of bending test or placing in the air for one month. Furthermore, the multistage structure film shows excellent Joule heating performance and can maintained for a long time. This work provides a simple and effective strategy for the preparation of multifunctional flexible patches, which have great application potential in the fields of EMI shielding and thermal management.

To Monitor Fracture Behaviors in Four-Point Cyclic Bending Tests of Low-Activated High Alumina Concrete and Standard Concrete RC Beams Using Acoustic Emission Technique

In this study, acoustic emission monitory (AE) was used to observe and evaluate the mechanical behavior of two kinds of RC beam members, made of low-activation concrete and normal concrete, by general four-point bending test and cyclic four-point bending test. During the loading, acoustic emissions due to cracking, shearing, rubbing, de-bonding or interlocking could be monitored and recorded using a real-time high sampling rate DAQ system and proper sensors; besides, beam displacement, cracking situation and loading were also measured simultaneously. The experiment goals included: (1) to observe the damage mechanisms of the beams under bending test and their corresponding AE performance; and (2) to observe the material fracture and corresponding AE in the beams under the cyclic bending test of 0.5Hz (periodic dynamic condition). After experiments, the fracture history of the beam under general loading test could be revealed through the comparison for the chronicled AE signal density and load/strain data. The damage on beam under the cyclic test could be analysed through the chronological comparison for the cumulative sum of AE signal counts obtained for different test periods and stages. Both the irreversibility on fracture mechanism (affected by the Kaiser effect) and the “remainder toughness” could be discussed through the quantitative analysis on AE characteristics for two different beams. They might relate to the durability and toughness of material for beam.

Biomechanical Properties of Novel Porous Scaffold Core and Hollow Lateral Hole Pedicle Screws: A Comparative Study in Bama Pigs.

Screw loosening is a common complication of internal fixation of pedicle screw. Therefore, the development of a pedicle screw with low loosening rate and high biosafety is of great clinical significance. This study aimed to investigate whether the application of a porous scaffold structure can improve the stability of pedicle screws by comparing the biomechanical properties of novel porous scaffold core pedicle screws (PSCPSs) with those of hollow lateral hole pedicle screws (HLHPSs) in a porcine lumbar spine. Thirty-two pedicle screws of both types were implanted bilaterally into the L1-4 vertebrae of four Bama pigs, with our newly designed PSCPSs on the right and HLHPSs on the left. All the Bama pigs were sacrificed 16 weeks postoperatively, and the lumbar spine was freed into individual vertebrae. Biomechanical properties of both the pedicle screws were evaluated using pull-out tests, as well as cyclic bending and pull-out tests, while the mechanical properties were assessed using three-point bending tests. The data generated were statistically analyzed using paired-sample t-tests and two independent sample t-tests. We found that the maximal pull-out forces before and after cyclic bending of the PSCPSs (1161.50 ± 337.98 N and 1075.25 ± 223.33 N) were significantly higher than those of the HLHPSs (948.38 ± 194.32 N and 807.13 ± 242.75 N) (p < 0.05, p < 0.05). In 800 cycles of the bending tests, neither PSCPS nor HLHPS showed loosening or visible detachment, but their maximal pull-out forces after cyclic bending tests decreased compared to those in cycles without cyclic bending tests (7.43% and 14.89%, respectively), with no statistical significance (p > 0.05 and p > 0.05, respectively). Additionally, both screws buckled rather than broke in the three-point bending tests, with no statistically significant differences between the maximal bending load and modulus of elasticity of the two screws (p > 0.05 and p > 0.05, respectively). Compared with the HLHPSs, the PSCPSs have greater pull-out resistance and better fatigue tolerance with appropriate mechanical properties. Therefore, PSCPSs theoretically have significant potential for clinical applications in reducing the incidence of loosening after pedicle screw implantation.

High electrical conductivity and bending resistance of Ag NPs/Ag flakes composite silver paste are achieved by sintering Ag NPs

The investigation of conductive silver pastes and inks has witnessed extensive research within the domain of printed electronics in recent years, primarily owing to the exceptional electrical conductivity and steadfastness intrinsic to silver. This paper introduces an approach for the fabrication of stable, cost-effective, and low-resistance conductive silver paste tailored for flexible printed circuits. This method facilitates the solidification of the conductive silver paste into a highly conductive silver film at a curing temperature of 250 °C. In the process of preparing the conductive silver paste, Ag flakes is subject to modification through the incorporation of Ag NPs, which are subsequently sintered at a low temperature curing setting. The sintering of Ag NPs serves to establish connections between adjacent particles of Ag flakes within the paste, thereby enhancing the conductivity and flexibility of the resulting conductive printed silver film. When the ratio of Ag NPs to Ag flakes is maintained at 10:90, the volume resistivity of the Ag NPs-modified film registers at 2.7 × 10−5 Ω.cm. This demonstrates a substantial 53.45% reduction in the volume resistivity of the conductive printed silver film modified with Ag NPs, compared to its Ag NPs-absent counterpart. Post 200 cyclic bending tests, it becomes evident that the resistance change rate in the Ag NPs-modified conductive printed silver film is a mere 12.5%, whereas the Ag NPs-modified silver film lacking Ag NPs displays a resistance change rate of 21.5%. This discrepancy underscores the capacity of Ag NPs-modified Ag flakes to fortify the bending resistance of the conductive printed silver film. Comprehensive data analysis substantiates that the improvements in electrical conductivity and bending resistance can be attributed to the superior bridging facilitated by the sintering process on the surface of the Ag NPs-modified Ag flakes.

Robustly and Intrinsically Stretchable Ionic Gel-Based Moisture-Enabled Power Generator with High Human Body Conformality.

Direct harvesting of energy from moist air will be a promising route to supply electricity for booming wearable and distributed electronics, with the recent rapid development of the moisture-enabled electricity generator (MEG). However, the easy spatial distortion of rigid MEG materials under severe deformation extremely inconveniences the human body with intense physical activity, seriously hindering the desirable applications. Here, an intrinsically stretchable moisture-enabled electricity generator (s-MEG) is developed based on a well-fabricated stretchable functional ionic gel (SIG) with a flexible double-network structure and reversible cross-linking interactions, demonstrating stable electricity output performance even when stretched up to 150% strain and high human body conformality. This SIG exhibits ultrahigh tensile strain (∼600%), and a 1 cm × 1 cm SIG film-based s-MEG can generate a voltage of ∼0.4 V and a current of ∼5.7 μA when absorbing water from humidity air. Based on the strong adhesion and the excellent interface combination of SIG and rough fabric electrodes induced by the fabrication process, s-MEG is able to realize bending or twisting deformation and shows outstanding electricity output stability with ∼90% performance retention after 5000 cycles of bending tests. By connecting s-MEG units in series or parallel, an integrated device of "moisture-powered wristband" is developed to wear on the wrist of humans and drive a flexible sensor for tracking finger motions. Additionally, a comfortable "moisture-powered sheath" based on s-MEGs is created, which can be worn like clothing on human arms to generate energy while walking and flexing the elbow, which is promising in the field of wearable electronics.

Mechanical responses and deformation mechanisms in the AZ31 magnesium alloy during cyclic bending

Cyclic loading behavior, such as cyclic bending, is unavoidably involved in various forming processes and the service of end products. Understanding the mechanical behavior of magnesium (Mg) alloys under cyclic bending is essential for promoting their application. Despite existing research, the microscopic mechanisms at play during cyclic bending, specifically the slip and twinning-de-twinning (TDT), warrant further exploration, which is the innovative focus of our study. To address this need, cyclic bending tests were performed on an extruded AZ31 Mg plate with the in-situ digital-image-correlation (DIC) technology. And the texture evolution was determined through electro backscattered diffraction (EBSD) measurements. Concurrently, the crystal-plasticity-based bending-specific approach, EVPSC-BEND, incorporating the TDT scheme, is utilized to interpret the mechanisms involved in cyclic bending. The impact at the macroscopic level is manifested in asymmetric cyclic moment-curvature curves, stress-strain distribution, and shifting of the neutral layer. The developed textures at different regions of the beam and the twin volume fraction distribution further directly illustrate twinning-de-twinning behaviors. Particularly, the upper and lower halves of the beam experience very distinct cyclic behaviors simultaneously. The upper half experiences a twinning, detwinning, and twinning cycle, while the lower half experiences a twin-free, twinning, and detwinning cycle. Additionally, through modeling the cyclic bending with different initial textures, the strong texture dependence has been revealed. The behaviors of magnesium alloy beam under cyclic bending discovered in this work can shed light on the application of Mg alloys, such as forming processes and service of end product.

High‐Performance Thermoelectric and Electromagnetic Interference Shielding Derived from MXene/Ag2Se Nanowire Composite Film

AbstractA flexible n‐type composite film consisting of MXene/Ag2Se nanowires (MX‐AS), is synthesized herein via a facile wet chemical sintering process. The thermoelectric properties of the composites with various MXene concentrations are systematically explored. The as‐synthesized 2D MXene exhibits homogeneous intercalation and dispersion of the Ag2Se nanowires. A comparative analysis reveals that these composite films outperform the pristine Ag2Se nanowire films fabricated using the same process. Specifically, the MX‐AS composite film containing 1.5 wt.% MXene exhibits a significant (≈1.25 times) improvement in the maximum thermoelectric power factor (PF), exhibiting a value of ≈933.4 µW m−1 K−2 at 400 K. This enhancement can be attributed to the combination of the remarkable intrinsic Seebeck coefficient of the Ag2Se and the high electrical conductivity of the MXene. Moreover, cyclic bending tests demonstrate the exceptional mechanical durability and flexibility of the composite film, with only an ≈7% decrease in the PF after 1000 cycles. In addition, the as‐prepared MX‐AS composite exhibits a high electromagnetic interference (EMI) shielding efficiency.

High-performance orthorhombic correlated transparent conducting epilayer integrated on a flexible mica substrate: The case of CaMoO3

Recently, cubic perovskite SrTMO3 (TM = V, Nb, and Mo) compounds have attracted great interest as correlated transparent conducting oxides (CTCOs). However, in theory, none of these three oxides is capable of completely covering the entire visible (Vis) light wavelength range with transparency. Herein, epitaxial orthorhombic CaMoO3 thin films were grown on flexible mica substrates using a pulsed laser deposition (PLD) method. By exploiting the tilting of MoO6 octahedra, an optimal balance between plasma energy (ћωp) and electrical conductivity (σ) was realized in CaMoO3. Electronic transport characterizations indicated that the σ value of CaMoO3 is comparable to that of SrTMO3. The optical transmittance spectra demonstrated that the CaMoO3 film possesses superior Vis transparency compared to SrTMO3. From the ellipsometry analysis, it was found that the O 2p – V 3d interband transition occurs at around 4.16 eV while the screened plasma energy (ћωp) is approximately 1.37 eV. The favorable absorption edges for both the long and short wavelength regions ensure the high transparency of CaMoO3 across the entire Vis spectrum. Additionally, bending cyclic tests illustrated the excellent mechanical durability and endurance of the CaMoO3/mica films. The present work is instructive for exploring alternative CTCOs beyond SrTMO3, demonstrating that the optimal balance between ћωp and σ can be realized by manipulating the TMO6 octahedral tilting to improve the transparent conducting performance of correlated perovskite-type oxides.

Vibration monitoring and acoustic emission sensing during progressive load tests of corroded reinforced concrete beams

Corrosion of reinforcement in concrete civil structures poses a significant challenge to their integrity and durability. To ensure the safety and longevity of such structures, effective monitoring strategies that can accurately detect, localise and assess the progression of damage are crucial. For most existing concrete structures, this is often challenging, as damage is already present when the monitoring campaign starts. In addition, reinforced concrete structures can be subject to a combination (or a succession) of corrosion and load-induced damage. By combining multiple measurement techniques, a more accurate and reliable condition assessment of concrete civil structures can be aimed for. This paper presents a comprehensive experimental study of the combination of vibration-based monitoring (VBM) and acoustic emission (AE) sensing techniques during progressive load tests of corroded reinforced concrete beams. Five beams were subjected to a cyclic four-point bending test, three of which were previously corroded while two beams remained undamaged prior to the mechanical loading. The influence of pre-existing corrosion damage and corresponding longitudinal concrete cracking on the modal characteristics (natural frequencies and strain mode shapes) and AE outcomes is investigated during the four-point bending test. The monitoring results obtained by both techniques are shown to be influenced by the pre-existing longitudinal concrete cracking caused by the reinforcement corrosion. Lower AE activity and a lower reduction in natural frequencies is observed for corroded RC beams during load bending tests when compared to uncorroded specimens. In addition, bending cracks occurring within the corroded zones appear to have a very limited effect on the identified strain mode shapes. These observations could possibly result in an underestimation of the damage and corresponding overestimation of the load-carrying capacity, as the corrosion damage conceals the occurrence of bending cracking on the AE and VBM outcomes.