Loss Of Tension Research Articles

Influence of stretch and temperature on the energy density of dielectric elastomer generators

Application of dielectric elastomers (DE) has remarkably increased in mechatronics because they are suitable candidates for energy harvesting due to their low cost, light weight, and high energy density. The dielectric elastomer generators (DEGs) exhibit high performance regardless of the applications scale. However, functioning as a generator, a DE may lose its efficiency due to several failure modes including material rupture, loss of tension (LT), electrical breakdown (EB), and electromechanical instability (EMI). The failure modes confine the area of allowable states for generation process. Dielectric constant and dielectric strength of such elastomers depend on the amount of applied deformation and also working temperature, which are often ignored in theoretical simulations. In this paper, variations of the above-mentioned parameters are considered in mechanical and electrical modellings to investigate their effects on energy density and efficiency of generators. Obtained results show that, ignoring the variations of material dielectric constant and dielectric strength leads to overestimation of the specific energy. Furthermore, it is shown that, for an acrylic-based generator, the specific energy sharply decreases with temperature rise.

Modelling nonlinear time-dependent pipeline walking induced by SCR tension and downslope

Subsea pipelines are important facilities in offshore oil and gas industry to transport High-Pressure and High-Temperature (HPHT) hydrocarbon. They are often exerted by cyclic thermal loading through the whole operational life, which may trigger asymmetry in the effective axial force (EAF) profile, leading to a global axial movement, defined as ‘pipeline walking’. It may cause the downtime and structural risks, since this directional accumulation in axial movement results in the overstressing of end connection, loss of tension in a steel catenary riser (SCR) and other issues in the field, therefore subsea pipeline design requires a reliable estimate of the global pipeline walking rate. Current design methods adopt a constant soil friction coefficient and ignore variations in soil-pipeline interaction with time during the heating up and cooling down processes. In reality, the overlooked changing soil friction is important, and may alter the pipeline walking behaviours. To achieve an accurate assessment of pipeline walking, this paper advances the conventional design practice, by introducing a time-dependent axial soil friction function, to examine the pipeline walking behaviour over the operational thermal cycles. A suite of time-dependent matrixes is provided to reveal the development of the expansion/contraction of the pipeline, the corresponding mobilised soil frictions and the EAF profile. The significant nonlinear EAF profile in response to the time-dependent soil friction is examined, and is used to well assess the accumulation in pipeline walking rate. The proposed analytical framework is applied into case studies to demonstrate its validity and applicability in practice.

Effect of the deformation dependent permittivity on the actuation of a pre-stretched circular dielectric actuator

Experiments have shown that under large deformation, the permittivity of some dielectric elastomers demonstrates significant deformation dependent behavior. In this paper, we theoretically analyze the effect of this behavior on the actuation of a circular actuator made of a dielectric elastomer, VHB 4910. The dependency of permittivity on deformation is considered through the equations of state. The equilibrium equations of the actuator are solved by MATLAB. The electromechanical instability, loss of tension and dielectric breakdown of the actuator during the actuation process under different pre-stretch levels are discussed. It is found that the dependency of permittivity on deformation can effectively suppress the electromechanical instability of the actuator at low pre-stretch levels. At high pre-stretch levels, however, it lowers the maximum stretch the actuator can achieve. Compared to the case of a constant permittivity, the deformation-dependent effect results in higher voltage needed to achieve the same actuated stretch, and this discrepancy in voltage increases as the pre-stretch increases. Furthermore, it is found that the maximum achievable stretch and the corresponding voltage show a strong dependence on factor c in the permittivity-stretch relation, while the stretch at the onset of loss of tension is independent of c.

Actin and myosin dynamics are independent during Drosophila embryonic wound repair.

Collective cell movements play a central role in embryonic development, tissue repair, and metastatic disease. Cell movements are often coordinated by supracellular networks formed by the cytoskeletal protein actin and the molecular motor nonmuscle myosin II. During wound closure in the embryonic epidermis, the cells around the wound migrate collectively into the damaged region. In Drosophila embryos, mechanical tension stabilizes myosin at the wound edge, facilitating the assembly of a supracellular myosin cable around the wound that coordinates cell migration. Here, we show that actin is also stabilized at the wound edge. However, loss of tension or myosin activity does not affect the dynamics of actin at the wound margin. Conversely, pharmacological stabilization of actin does not affect myosin levels or dynamics around the wound. Together, our data suggest that actin and myosin are independently regulated during embryonic wound closure, thus conferring robustness to the embryonic wound healing response.

The behavior of anchor lines embedded in layered soils

The behavior of deepwater anchors in the seabed is significantly affected by the anchor lines embedded in soils, whether in anchor installation or in mooring. Unlike the anchor lines submerged in seawater, the ones embedded in soils exhibit special and complex behaviors due to soil resistance in either tension transmitting or profile properties of the lines. This problem becomes more complicated when encountering a complex seabed condition, such as the layered soils with both cohesive and cohesionless layers. Full knowledge of the anchor lines embedded in layered soils is imperative for anchor installation and safe operation of mooring systems. The literature review indicates that the relevant studies apply only to a single layer of either cohesive or cohesionless soil. This highlights the importance of the present study and also the challenge to deal with the problem in layered soils composed of both cohesive and cohesionless layers. In the present work, a mechanical model as well as analytical procedures is proposed to analyze the tension transmitting and profile properties of anchor lines embedded in layered soils. This model can well capture the complexity of seabed conditions, applying to not only the layered soils with both cohesive and cohesionless layers, but also the cohesive or cohesionless layers with different soil strengths. To gain further knowledge of the behavior of anchor lines embedded in layered soils, numerous cases of layered soils are designed and analyzed by the present model. The results indicate that, the configuration of the embedded anchor line presents complex and various reverse catenary shapes due to different strengths of layered soils; companying with increasing curvature of the reverse catenary configuration, both the tension loss and the tension angle at the shackle of the anchor increase with increasing proportion of cohesionless layers. These phenomena exhibit the complexity and variety of the behavior of anchor lines embedded in layered soils. A specific case of such problems can be efficiently solved by the present model to gain quantitative analytical results.

Loss of retinal tension and permanent decrease in retinal function: a new porcine model of rhegmatogenous retinal detachment.

PurposePermanent loss of visual function after rhegmatogenous retinal detachment can occur despite successful surgical reattachment in humans. New treatment modalities could be explored in a detachment model with loss of retinal function. In previous porcine models, retinal function has returned after reattachment, regardless of height and duration of detachment. Difference in retinal tension between the models and the disease might explain these different outcomes. This study investigates, for the first time in an in vivo porcine model, another characteristic of rhegmatogenous retinal detachment – the loss of retinal tension.MethodsLeft eyes (n = 12) of 3‐month‐old domestic pigs were included. Baseline multifocal electroretinogram (mfERG) and a fundus photograph were obtained following anaesthesia (isoflurane). The pigs were vitrectomized, saline was injected subretinally, and the RPE was removed. The eyes were evaluated at 2, 4 and 6 weeks after surgery. Four eyes were enucleated at each evaluation for histologic examinations.ResultsA retinal detachment structurally resembling rhegmatogenous retinal detachment was induced in 11 out of 12 pigs. MfERG amplitudes were significantly decreased despite partial reattachment four and 6 weeks after detachment. The retinal thickness decreased with 27%, the inner nuclear layer degenerated, Müller cells hypertrophied, and outer segments were lost. In the ganglion cell layer, cellularity increased and there was cytoplasmic staining with Cyclin D1. Vimentin and GFAP staining for glial cells increased. After 2 weeks of detachment, the ganglion cells had lost their nucleus and nucleolus.ConclusionsLoss of retinal tension in the detached retina seems to induce permanent damage with loss of retinal function. Death of ganglion cells, observed as soon as 2 weeks after detachment, explains the permanent loss of retinal function. The new model enables investigations of time‐relationship between retinal detachment and lasting damage in addition to exploration of novel treatment modalities.

Finite element modeling of cable sliding and its effect on dynamic response of cable-supported truss

The cable system of cable-supported structures usually bears high tension forces, and clip joints may fail to resist cable sliding in cases of earthquake excitations or sudden cable breaks. A analytical method that considers the dynamic cable sliding effect is proposed in this paper. Cable sliding behaviors and the resultant dynamic responses are solved by combining the vector form intrinsic finite element framework with cable force redistribution calculations that consider joint frictions. The cable sliding effect and the frictional tension loss are solved with the original length method that uses cable length and the original length relations. Then, the balanced tension distributions are calculated after frictional sliding. The proposed analytical method is achieved within MATLAB and applied to simulate the dynamic response of a cable-supported plane truss under seismic excitation and sudden cable break. During seismic excitations, the cable sliding behavior in the cable-supported truss have an averaging effect on the oscillation magnitudes, but it also magnifies the internal force response in the upper truss structure. The slidable cable joints can greatly reduce the ability of a cable system to resist sudden cable breaks, while strong friction resistances at the cable-strut joints can help retain internal forces.

Strain behavior of native and reconstructed medial patellofemoral ligaments during dynamic knee flexion - a cadaveric study

BackgroundSurgical reconstruction of the Medial Patello-Femoral Ligament (MPFL) has been recognized as an effective treatment for patients with instability despite conservative treatment. The purpose of this cadaveric study is to compare the strain patterns within the native and reconstructed single and double-bundle MPFL. This will help ascertain if the native biomechanics are restored with the reconstructions.MethodsTwelve cadaveric knees were dissected and the native MPFL of each specimen was identified. The knees were subjected to dynamic flexion using a customized jig. Continuous strain measurements were taken for each knee from 0 to 120 degrees flexion and then back to full extension using differential variable reluctance transducers (DVRTs). The MPFL was then cut. Six single bundle and six double bundle MPFL reconstructions were performed using hamstring tendon grafts. The DVRTs were reattached to the grafts and strain measurements were retaken. Statistical analysis was performed using a paired t-test.ResultsStrain patterns of the native and reconstructed MPFL showed an increase in strain from 0 to 120 degrees of flexion except for the inferior bundle of the double bundle reconstruction. The strain patterns in the intact specimens were higher than the reconstructed MPFL through different degrees of knee flexion. In the double-bundle group, the superior graft had statistically significantly lower strains compared to the native MPFL with p-value <.05 at all flexion angles. The reconstructed inferior band showed loss of tension as the knee flexed. Higher strain with statistical significance (p-value <.05) was found in the single-bundle compared to the superior band of the double-bundle reconstruction at flexion angles less than 90 degrees.ConclusionThe strain variation at progressive angles of knee flexion is dissimilar between the native and reconstructed MPFL. The reconstructed MPFL exhibited non-physiological biomechanics with the inferior band losing tension. Although the single-bundle reconstruction shows a better strain profile compared to double-bundle reconstruction, the grafts are significantly stiffer than the native MPFL.

Abstract 1028: Extracellular matrix dimensionality reduces cellular cortical tension to stimulate pro-survival signaling in mammary epithelial cells

Abstract Tumor dormancy is a clinical phenomenon in which disseminated tumor cells remain asymptomatic and undetectable over a long period of time. Dormant cells are able to maintain quiescence in hostile microenvironments, escape frontline cancer therapies and evade the immune system, as well as their propensity to reactivate from latency and cause metastatic relapse. Although tumor dormancy is an important problem in the treatment of cancer, the molecular mechanisms underlying this complex process remain unclear. Because dormant cells are frequently found surrounded by a laminin-rich ECM, we hypothesized that ECM dimensionality intrinsically affects cell behaviors that predispose to dormancy. Accordingly, we assessed the biophysical and biochemical response of mammary epithelial cells (MECs) to compliant polyacrylamide (PA) gels and micropatterned surfaces in which ligand presentation and ECM dimensionality were modulated to recapitulate different ECM landscapes. Using traction force microscopy, atomic force microscopy indentation, and laser ablation studies, we found that a 3D ECM led to a drop in cortical tension of MECs. Computational modeling predicted that reduced cortical tension should lead to an increase in the number and/or residence time of actin protrusions as well as a net increase in negative membrane curvature. To test the prediction, we ectopically expressed F-actin and plasma membrane markers in MECs to examine the plasma membrane topography and actin protrusion dynamics. Indeed, MECs in 3D ECM had longer and more stable actin protrusions and more negative membrane curvature inducing proteins, including Exo70, at the plasma membrane. The enrichment of Exo70 at the plasma membrane accompanied the activation of Arf6, which led to an increase in Rac/p38 pro-survival signaling pathway. Consistently, we found that the non-spread cells were able to survive in 3D ECM but the non-spread MECs plated on either a soft 2D PA gels or rigid micropatterned adhesive islands died. We next examined if reduced cortical tension is sufficient to activate pro-survival pathways in cells in 2D. Importantly, pharmacological inhibition of myosin in non-spread MECs on a 2D ECM, which causes loss of cortical tension, increased negative membrane curvature and cell viability. Conversely, genetic knockdown of the negative curvature-inducing protein Exo70 compromised MEC survival in a 3D ECM. Our results provide the first evidence demonstrating that ECM dimensionality alters the biophysical properties of cells to modulate plasma membrane curvature and activate pro-survival signaling pathways. Our findings also offer a unique perspective for why Arf6 and Rac GTPases have been implicated in cancer aggression and suggest that targeting the tissue ECM or cellular cortical tension may provide a novel therapeutic approach to target dormant cells. Citation Format: FuiBoon Kai, Guanqing Ou, Alexandra Long, Wei Guo, Richard Tourdot, Ravi Radhakrishnan, Christopher Chen, Sophie Dumont, Valerie M. Weaver. Extracellular matrix dimensionality reduces cellular cortical tension to stimulate pro-survival signaling in mammary epithelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1028.

RATIONALE FOR THE USE OF DOUBLE SHOULDER THREADED CONNECTIONS OF HOLLOW SUCKER RODS

Frequent failures of standard threaded connections of hollow sucker rods are caused by their fatigue failures, self-loosening and leakages. This is mainly caused by such design flaws as unequal load on threads, insufficient shoulder area, stress concentration in the groove, low resistance to bending and torsion loads. Using iterative design, based on parametric geometric modeling and the finite element method, the feasibility of using double shoulder threaded connections for hollow sucker rods has been proved and their design has been improved. The improved connection has two shoulders, modified grooves with an elliptical profile, correction of the first turn of the nipple thread and optimal values of interferences. Due to this, the joint has greater tightness, strength at bending, torsion and compression, higher resistance to self-loosening, more equal load on the threads and greater fatigue strength compared to the standard one. The value of the fatigue safety factor in the area of the first turn of the nipple thread is increased by 13...14, in the area of the last turn of the coupling – by 2.6...4, in the area of the nipple groove by 0…0.4. The use of an elastic element on an additional shoulder allowed increasing the tolerance of the interference on it to 0.2 mm, making it unnecessary to control dimensions before screwing. Even after damage to the elastic part and loss of tension on an additional shoulder, the connection has greater strength than the standard one. In case of rod repairs, improved nipples can be easily implemented by welding them to the rod body. There is also the possibility of implementation of double shoulder cylindrical connections without modifying the standard nipple.

Tensile Stress Generation on Crystallization of Polymer Networks

When crystallized under constant strain, conventional semicrystalline networks exhibit a loss in tension due to directionally preferred crystallization of chains along the strain axis. This study shows that a dual-cured, semicrystalline polymer network with programmed chain bias can generate ∼400 kPa of tensile stress upon crystallization. Constant strain experiments were conducted to monitor stress in configurationally biased networks as they were cooled and crystallized. Time resolved wide-angle X-ray scattering was used to study crystallization kinetics and the evolution of crystallite orientation. In configurationally biased networks without external load, initial crystallization along the internal chain bias direction is rapidly followed by crystal growth in the orthogonal direction. Under external loads, crystallization first occurs along the external load direction followed by the configurational chain bias direction. Calorimetry measurements indicate that two distinct crystal populations form upon...

Experimental Evaluation of Vibration Response of External Post-Tensioned Tendons with Corrosion

This study investigates the vibration responses of external post-tensioned (PT) tendons based on experimental data. The vibration signals measured from four large-scale external post-tensioned tendon specimens subjected to localized corrosion until severe level of damage were accumulated. A series of impact tests was conducted to measure lateral vibration signals and the variation in the tension was continuously monitored using a load cell. The acquired vibration signals were evaluated using an axially-tensioned beam model in which the properties were varied to reflect the loss of tension and the reduction in the bending stiffness caused by corrosion damage. A comparison between the experimental data and the analytical results indicates that the natural frequencies were shifted as the residual tension decreased but were influenced by corresponding grout damage in a limited range. As a result, the frequency response was not appreciably affected by the damage level and the tension remained as the primary structural parameter of the external PT tendon with damage.

Hang on tight: reprogramming the cell with microstructural cues.

Cells interact intimately with complex microdomains in their extracellular matrix (ECM) and maintain a delicate balance of mechanical forces through mechanosensitive cellular components. Tissue injury results in acute degradation of the ECM and disruption of cell-ECM contacts, manifesting in loss of cytoskeletal tension, leading to pathological cell transformation and the onset of disease. Recently, microscale hydrogel constructs have been developed to provide cells with microdomains to form focal adhesion binding sites, which enable restoration of cytoskeletal tension. These synthetic anchors can recapitulate the complex 3D architecture of the native ECM to provide microtopographical cues. The mechanical deformation of proteins at the cell surface can activate signaling cascades to modulate downstream gene-level transcription, making this a unique materials-based approach for reprogramming cell behavior. An overview of the mechanisms underlying these mechanosensitive interactions in fibroblasts, stem and other cell types is provided to review their effects on cellular reprogramming. Recent investigations on the fabrication, functionalization and implementation of these materials and microtopographical features for drug testing and therapeutic applications are discussed.

Pull Out and Creep Behaviour of Soil Nailing – A Case Study

The use of soil nails for slope strengthening is one of the popular methods since 1980s due to the attractive benefits of simple and fast installation method to reinforce cut slope. Proper assessment of the soil nail behavior between the nails and the surrounding soil will contribute to the safe and economical design of the reinforced soil structure. At present, the safety factor is adapted to soil nailing design and analysis, however, some soil nailed slope, which are designed, in compliance to the slope guidelines end up with failure. For the current knowledge, there is limited information on the loss of the shaft friction in soil nailing due to creep and the research on the behavior of the soil nail is also limited. Hence, in order to provide additional information on the behavior of the conventional soil nailing system, the bore holes and pull out test data were collected from the various projects: 1) Cheras, Kuala Lumpur, 2) Penang Hill, Penang, and 3) Kajang, Selangor. This study is focused on the behavior of the soil nail under pull out test at various types of soils and different soil nails characteristics. The parameters measured are soil nail pull out resistance and displacement of soil nails under different loading. In addition, the creep behavior of the soil nail was a study based on the displacement under maintain period at maximum test load during the pullout test. The creep behavior of soil nail is causing the loss of tension in the soil nail and that affecting the performance of the engineered slope. For the study and result presented, it is clear that soil nail under certain types of soil, especially dry, poorly graded cohesionless soils or soil with high water table is creep susceptible and had a lower pull out resistance. Pull out test on soil nail installed in medium stiff clayey Silt and sandy Silt and socketed in rock is performing up to design expectation.

Elastocapillary Crease.

A material under compression often forms creases. When the material is elastic and soft, the nucleation of creases depends on both elasticity and capillarity. Here we introduce a model of elastocapillary creases. The model assumes that the surface tension remains constant on the free surface, but may change upon self-contact. In particular, surface tension vanishes upon self-contact for a pristine surface of elastomers and gels. The model predicts that the nucleation of creases depends on the sizes of surface defects relative to the elastocapillary length, and happens over a well-defined range of strains, instead of a specific strain. The loss of surface tension upon self-contact lowers the energy barrier for nucleation, and widens the range of nucleation strains for materials of any thickness relative to the elastocapillary length. We test this model by conducting experiments with materials of various elastocapillary lengths, along with the data available in the literature.

Increasing the Utilization of Transmission Lines Capacity by Quasi-Dynamic Thermal Ratings

The power grid is under pressure to maintain a reliable supply because of constrained budgets and environmental policies. In order to effectively make use of existing transmission lines, it is important to accurately evaluate the line capacity. Dynamic thermal rating (DTR) offers a way to increase the utilization of capacity under real-time meteorological data. However, DTR relies on a number of sensors and the cost is high. Therefore, a method of improving the utilization of capacity by quasi-dynamic thermal rating (QDR) is proposed in this paper. QDR at different confidence levels and time scales is determined through the statistical analysis of line ampacity driven by key parameters, and the key parameters is identified by control variate method. In addition, the operation risk and tension loss is evaluated. The results show that QDR can increase the utilization of line capacity and in the absence of along-line measuring devices, QDR is more accurate, reliable and cost-saving. The managers can determine the appropriate confidence level according to the operation risk and tension loss that the system can bear, and shorten the time scale with the permission of the operation and control complexity.

Fibrin Density and Tension Regulates Fibrinolytic Susceptibility

Fibrin fibers provide structural and mechanical integrity to blood clots until their dissolution during fibrinolysis. This work seeks to deconvolve the respective fibrinolytic influences of enzyme kinetics and enzyme perfusion rates into clots from clot structure and fiber properties. Here we consider the lysis of fibers within small, 2-D networks, which have polymerized between ridges. We tracked changes in fiber morphology within a 24-hour period during lysis. We find that fibers follow several possible degradation pathways during the lytic process including transverse cleavage, fiber bundling, structural elongation due to network rearrangements, tension loss, and network collapse. Transverse cleavage of individual fibers results in network rearrangements due to the redistribution of the tension in the yet-to-be-cleaved fibers. Network rearrangements and remnants of cleaved fibers often lead to fibers bundling into thicker fibers which are more resistant to fibrinolysis. When the final strand holding the network in place is transversely cleaved, the remaining fibers recoil and collapse onto the ridge. These effects highlight the inherent tension in fibrin networks and its role in governing fibrinolytic degradation. This is further emphasized by the observation that lysis kinetics depend strongly on fiber density. Fibers in high-density areas, and presumably under more tension, lyse at earlier time points and more rapidly than fibers in low-density areas. Fibrinolysis initiated with low (0.1 U/mL) concentrations of plasmin occurs more slowly than with high (1.0 U/mL) concentrations of plasmin, and structural rearrangement due to tension redistribution is more prominent. These results identify the different pathways whereby a fibrin network is cleared out of an area by the lytic enzyme plasmin. Inherent fiber tension plays an important role in regulating this process.

Study on key performance parameters of hydro-pneumatic tensioner for top tensioned riser

In this paper an improved mathematical model of a hydro-pneumatic tensioner (HPT) system for top tensioned riser (TTR) is derived by consideration of friction, mass of piston and piston rod, tension loss in hydraulic oil piping, and compressibility of hydraulic oil. The vertical motion of the riser string is also considered. Subsequently, the proposed detailed model and the conventional simplified model are comparatively studied. Finally, the tension characteristic and performance parameters of the HPT are analyzed based on the proposed model. Results show that the conventional simplified model indeed overestimates the tension of tensioner as it neglects some performance parameters resulting in tension loss. The diameters of piston and piston rod and the initial pressure of high pressure (HP) gas have the most significant influence on the tension of the tensioner. The initial volume of HP gas and the initial pressure of low pressure (LP) gas also have some impact. The influence of the initial volume of LP gas and the inner diameter and length of the piping is relatively small. The research has some reference value for HPT and TTR design.

Instabilities in dielectric elastomers: buckling, wrinkling, and crumpling.

Instabilities in a thin sheet are ubiquitous and can be induced by various stimuli, such as a uniaxial force, liquid-vapor surface tension, etc. This paper investigates voltage-induced instabilities in a membrane of a dielectric elastomer. Instabilities including buckling, wrinkling, and crumpling are observed in the experiments. The prestretches of the dielectric elastomer are found to play a significant role in determining its instability mode. When the prestretch is small, intermediate, or large, the membrane may undergo buckling, wrinkling, or crumpling, respectively. Finite element analysis is conducted to study these instability modes, and the simulations are well consistent with the experimental observations. We hope that this investigation of mechanical and physical properties of dielectric elastomers can enhance their extensive and significant applications in soft devices and soft robots.

Residual resource of force resistance to deformation

The problem of the durability of reinforced concrete structures of urban engineering structures is currently one of the urgent problems in modern construction due to the continuously growing volume of expensive repair and restoration work, facilities reconstruction, a tendency to a general decrease in quality requirements, and the scale of reinforced concrete structures application in difficult climatic conditions. The theoretical foundations of calculating the residual life of the force resistance to transverse bending with the strength of normal sections in the article, algorithms for calculating the residual life of the force resistance and reinforcement of corrosion-damaged reinforced concrete structures are defined. A complex calculation method is considered in this article that allows to quantitatively assessing the state and resources of crack resistance of reinforced concrete structures damaged by corrosion, to calculate the necessary levels of compression and loss of tension, as well as the exposure to preserve crack resistance in time at specific loading levels and intensities of corrosion effects. The developed complex calculation method can be presented as part of the solution to the problem of preventing and eliminating emergency situations. The theoretical basis for calculating the residual resource of strength resistance to transverse bending by the strength of inclined sections are discussed in the article, the calculation algorithms are studied, and examples are given.