Uneven Stress Distribution Research Articles

Steady‐State Inverse‐Temperature Crystallization Enabling Low Defect Perovskite Single Crystal and Efficient X‐Ray Detectors

AbstractOrganic–inorganic halide perovskite single crystals (SCs) have shown great potential in radiation detection applications due to their large radiation stopping power and excellent carrier transport properties. The spatial‐confined inverse‐temperature crystallization (ITC) method has been widely adopted to obtain large‐sized SCs. However, they usually face the problems of uneven stress distribution and high defect density due to the limited crystal growth space and varied growth rate with the increase in temperature, making it difficult to fabricate highly sensitive and stable radiation detectors. In this study, the steady‐state inverse‐temperature crystallization method (SS‐ITC) is developed to regulate the growth process of SCs by controlling the growth speed precisely to achieve a constant rate of growth as the temperature increases. Compared with the conventional ITC‐grown samples, the lattice spacing of SCs prepared by the SS‐ITC method is reduced by 1.2% due to tensile stress relaxation, resulting in a lower defect density of 7.93 × 109 cm−3 and a remarkable uniformity over a large area. As a result, the co‐planar X‐ray detectors based on these high‐quality SCs exhibit a high sensitivity of 1.67 × 105 µC Gyair−1 cm−2, representing the best performing MAPbBr3‐based X‐ray detectors reported to date.

Bond performance and damage assessment of self-sensing steel–fiber composite bar with geopolymer concrete

This study employed a novel steel–fiber composite bar (SFCB) enhanced with Distributed Optical Fiber Sensors (DOFS) technology to reveal the local bonding and damage mechanisms between composite reinforcement and seawater sea sand geopolymer concrete. By embedding DOFS within the steel core of the SFCB reinforcement, the local bond stress between the reinforcement and geopolymer concrete was monitored. The continuous measurement provided by DOFS revealed a non-uniform strain distribution along the length of the SFCB reinforcement and an uneven distribution of bond stress within the bonded section. Based on test results, a modified bond–slip model was utilized to predict the bond–slip relationship between the SFCB reinforcement and the geopolymer concrete, taking into account the influence of surface treatment on the descending branch of the bond–slip curve. Additionally, a damage model was employed to evaluate the extent of damage at the bond interface between the SFCB reinforcement and the geopolymer concrete under different load levels. Finally, the modified bond–slip model was also used to propose the anchorage length for SFCB reinforcements, which was compared with ACI, CSA, and JSCE codes.

Failure mechanism analysis and treatment of tunnels built in karst fissure strata: A case study

With the rapid increase of tunnels built in karst fissure strata, much more problems appeared during the construction process. Based on the Liangwangshan Tunnel, this article presents a case of tunnel failure by karst fissure, and the failure mechanism and treatment were analyzed. Firstly, when the karst fissure was close to the excavation face, A large area of cavity appeared above the right spandrel, which was distributed diagonally with a narrow shape. However, the pressure on the left side was greater than it on the right side near the karst fissure by on-site monitoring. Secondly, laboratory tests were carried out to determine that the karst fissure weakened the strength of surroundings, especially in shear and tensile strength. The results of theoretical analysis and discrete element method considering the joints indicated that karst fissure will exacerbate the uneven stress distribution and prevent the transmission of stress. The failure mode can be manifested as bending fracture and shear fracture, and the tensile shear composite failure mainly occurred on tunnel near the fissure. Finally, the radial grouting and advanced pipes have been implemented on site, and the on-site monitoring showed that the treatment measures were effective to control the failure when tunnel was excavating. The research can provide guidance for the similar tunnel engineering built in karst fissure strata.

Analysis of microstructure of prefabricated fractured granite under thermal effects based on CT technology

In this study, Computed Tomography (CT) technology was employed to visually analyze the influence of thermal effects on the microstructure of prefabricated fractured granite. The porosity and heterogeneity of the samples were calculated using three-dimensional reconstruction techniques, and two parameters, crack length and orientation, were introduced to quantitatively evaluate the impact of prefabricated fractures on subsequent crack propagation. The results indicated that at 400 °C–500 °C, numerous microcracks were generated within the samples, but they did not interconnect. Above 600 °C, microcracks gradually propagated, forming well-connected crack networks. Due to the uneven thermal stress distribution caused by the prefabricated fractures, samples subjected to temperatures above 600 °C exhibited higher heterogeneity in the vertical direction. While in other directions, the samples gradually tended to homogenize as the temperature rose. Below 500 °C, crack length was significantly affected by the prefabricated fractures, although this influence diminished with increasing distance from the fractures. When the temperature was below 400 °C, microcracks mainly propagated along the direction of the prefabricated fractures. However, when the temperature exceeded 500 °C, microcracks began to initiate and propagate in the opposite direction of the prefabricated fractures, and anti-wing cracks started to emerge.

Hydrodynamic Characteristics of Preloading Spiral Case and Concrete in Turbine Mode with Emphasis on Preloading Clearance

A pump-turbine may generate high-amplitude hydraulic excitations during operation, wherein the flow-induced response of the spiral case and concrete is a key factor affecting the stable and safe operation of the unit. The preloading spiral case can enhance the combined bearing capacity of the entire structure, yet there is still limited research on the impact of the preloading pressure on the hydrodynamic response. In this study, the pressure fluctuation characteristics and dynamic behaviors of preloading a steel spiral case and concrete under different preloading pressures at rated operating conditions are analyzed based on fluid–structure interaction theory and contact model. The results show that the dominant frequency of pressure fluctuations in the spiral case is 15 fn, which is influenced by the rotor–stator interaction with a runner rotation of short and long blades. Under preloading pressures of 0.5, 0.7, and 1 times the maximum static head, higher preloading pressures reduce the contact regions, leading to uneven deformation and stress distributions with a near-positive linear correlation. The maximum deformation of the PSSC can reach 2.6 mm, and the stress is within the allowable range. The preloading pressure has little effect on the dominant frequency of the dynamic behaviors in the spiral case (15 fn), but both the maximum and amplitudes of deformation and stress increase with higher preloading pressure. The high-amplitude regions of deformation and stress along the axial direction are located near the nose vane, with maximum values of 0.003 mm and 0.082 MPa, respectively. The contact of concrete is at risk of stress concentrations and cracking under high preloading pressure. The results can provide references for optimizing the structural design and the selection of preloading pressure, which improves operation reliability.

Investigation of the dynamic compression behavior of 3D braided composites based on a virtual fiber embedding method

The three-dimensional braided composites (3DBCs) possess a complex spatial structure, which can lead to microscopic deformation of fibers under high-speed impact. This paper proposes a quasi-fiber scale model using virtual fiber-embedded (VFE) method to simulate the impact behavior and failure of 3DBCs. The results reveal that the maximum eccentricity of the VFE model yarn cross-section is 0.318, representing a 194% improvement compared to solid yarns. According to the characteristics of damage, it can be deduced that interactions among fibers play a pivotal role in determining the failure behavior of composites, particularly concerning non-linear changes. The modulus, strength and the time of initial damage rise with an increasing braiding angle, whereas the resin stress, yarn stress, and degree of damage exhibit opposite trends. The stress distribution over the braiding path shows that the main load-bearing component at 20° braiding angles is internal yarns, whereas the surface yarns take precedence at 40°. The maximum deformation of the yarn cross-section always occurs at the center of the shear band, with a maximum eccentricity of 0.456 at 20° braiding angles. The deformation in yarn flexing and cross-section flattening cause an uneven distribution of stress and strain, leading to localized damage and ultimately catastrophic destruction.

Bond-Slip Constitutive Relationship between Steel Rebar and Concrete Synthesized from Solid Waste Coal Gasification Slag

Bond performance served as a crucial foundation for the collaboration between concrete and steel rebar. This study investigated the bond performance between coal gasification slag (CGS) concrete, an environmentally friendly construction material, and steel rebar. The effects of fine aggregate type, steel rebar diameter, and anchorage length on bond performance were examined through bond-slip tests conducted on 16 groups of reinforced concrete specimens with different parameters. By utilizing experimental data, a formula for the bond strength between steel rebar and CGS concrete was derived. Additionally, the BPE bond-slip constitutive model was modified by introducing a correction factor (k) to account for relative protective layer thickness. Findings indicated that substituting 25% of manufactured sand with coal gasification slag did not cause significant adverse effects on concrete strength or bond stress between concrete and steel rebar. The effect of steel rebar diameter on the ultimate bond stress was not obvious, whereas when the steel rebar diameter was fixed; the increase in anchorage length led to uneven distribution of bond stress and eventually reduced the ultimate bond stress. The modified bond-slip constitutive model agreed well with the experimental values and was able to more accurately reflect the bond-slip performance between CGS concrete and steel rebar. This study provided a theoretical basis for the conversion of CGS into a resource and for the application of CGS concrete.

Stress-relieved hollow porous carbon nanoring structures anchored with ZnCo2O4 nanoparticles towards super stable lithium storage

Stress-induced structural mechanical instability is a common occurrence in the electrode material during electrochemical cycling, especially for composite material systems. The structural mechanics engineering of nanocomposites comprising electrochemical active materials and carbon with novel structures holds great promise in addressing this issue. However, conventional carbonaceous materials often encounter challenges in long-term durability and high specific capacity stemming from their intrinsic uneven stress distribution and few active sites. Herein, finite element analysis reveals that the ring-like structure effectively mitigates stress concentration from expansion and possesses high packing density, outperforming traditional nanosphere and nanocube architectures. Accordingly, nanocomposites consisting of hollow porous nanostructured N-doped carbon nanorings (N-CNRs) anchored with bimetallic ZnCo2O4 nanoparticles are designed, which exhibit an extraordinary cycling performance for lithium storage with 96.4 % capacity retention following 1000 cycles and an impressively low storage degradation rate of 0.00357 % per cycle, as well as displaying an excellent specific capacity (1218 mA h/g at 0.1 A g−1) and outstanding rate performance (565 mA h/g at 5.0 A g−1). The well-engineered design nanocomposite features the synergistic effect of electrochemically active ZnCo2O4 nanoparticles integrated with structurally stable carbon nanorings for enhanced electrochemical performance.

Microstructural and electrical properties of La0.9B0.1AlO3 (B=Pr, Nd, Sm) ceramics obtained by rare-earth ion doping

This study used the solid-phase method to prepare thermosensitive perovskite ceramics, La0.9B0.1AlO3 (B = Pr, Nd, Sm). The XRD and EDS results indicated that all components presented a single phase and all elements were uniformly distributed, formed a good solid solution. The SEM results clearly illustrated that the doped elements had enhanced the surface morphology, resulting in more uniform grain formation. The TEM results showed that linear defects were present, which led to an uneven stress distribution; consequently, this enhanced the carrier transport. The alternating current (AC) impedance showed that the grain boundary resistance determined the overall complex impedance and exhibited a different conductive mechanism with increasing temperature, from polariton to ion conduction. With the introduction of Nd3+, the conductivity of La0.9Nd0.1AlO3 increased and its temperature range increased from 600 – 1400 °C to 100–1500 °C. In La0.9Sm0.1AlO3, the presence of Sm2+ enhances the aging stability by elevating the oxygen vacancy concentration and the aging drift rate (ΔR/R0) was found to be lower than 2 %. In addition, DFT-based calculations were performed to investigate the property changes in the crystal structure and energy band structure of pure and doped LaAlO3. This study demonstrated an effective way to improve the performance of high-temperature thermistor materials using different doping strategies.

Is it stable for the asymmetric pressure operation of PEM water Electrolyzer?

Benefiting from the high selectivity of solid polymer membrane in transporting protons, proton exchange membrane water electrolyzer (PEMWE) have the unique capability of safely operating under asymmetric pressure between the cathode and anode (typically with the cathode under elevated pressure and the anode at ambient pressure). This capability is crucial for high-pressure hydrogen storage and transportation, as well as for rapid response to fluctuating renewable electricity. Although increased cathode pressure significantly simplifies system integration and reduce capital cost, the stability under asymmetric pressure operation has not been well studied and reported. In this work, durability tests under different pressure differences were carried out, and it was found that when the pressure difference between cathode and anode increases from zero to 3.0 MPa, the voltage decay rate increased over 15 times. The underlying reason is that the asymmetric pressure imposes additional mechanical stress on the anode catalyst layer from cathodic side, leading to increase of mass transfer resistance and irreversible structural damage, resulting in performance degradation. In view of this fact, the internal structure of the electrolyzer cell was optimized, and the uneven stress distribution and stress concentration was greatly reduced, thus mitigating performance degradation. This indicates that the stability of PEMWE is significantly affected by asymmetric pressure, additional measures need to be taken to address potential issues of catalyst layer structural damage arising from stress.

A finite element analysis on the indication for extracting partially impacted mandibular third molars considering mandibular trauma

BackgroundPatients presenting with partially impacted lower third molars (M3) have a higher likelihood of experiencing angle fractures while simultaneously decreasing the risk of condylar fractures. However, the specific biomechanical mechanism responsible for this occurrence remains unclear. Moreover, there is an ongoing debate regarding whether the removal of M3s might actually increase the risk of condylar fractures. This study aimed to evaluate how the presence of M3s influences mandibular fractures resulting from blows to the symphysis and lateral mandibular body, and to determine the indication for extracting M3s in such cases.MethodsModels of the mandible with a partially M3-impacted model (M3I), M3-extracted model (M3E), and M3-absent model (M3A) were generated using a computer. A traumatic blown force of 2000 N was applied to the symphysis and the right body of the mandible. Von Mises and principal stresses were analyzed, and failure indexes were determined. Two cases of mandibular linear fractures were chosen for model verification and interpretation.ResultsWhen force was applied to the symphysis, the condylar region exhibited the highest stress levels, while stress in the mandibular angle region was much less regardless of the M3 state. On applying the force to the right mandibular body, stress in the condylar region decreased while stress in the mandibular body increased, especially in the blown regions. Impacted tooth or cavity formation post-M3 extraction led to uneven stress distribution on the blown side of the mandible, increasing the risk of mandibular angle fractures. In cases where M3 was absent or the extraction socket had healed, stress from lateral traumatic blown force was evenly distributed along both the inner and outer oblique lines of the mandible, thereby reducing the risk of mandibular fractures.ConclusionsThe reduced risk of condylar fractures in patients with partially impacted lower M3s and mandibular angle fractures is mainly due to lateral blows on the mandible, which generate less stress in the condylar region than blows on the mandibular symphysis, rather than being caused by the M3 itself. Extraction of the lower M3 can decrease the risk of mandibular fractures, with a minor influence on condylar fractures.

Wear characteristics evolution of helical gear with initial defects of bearing inner ring

This study investigated the wear characteristics and operational condition of gears with initial defects of the bearing inner ring. The working states of gears were evaluated through a combination of vibration signal analysis, wear debris concentration analysis, qualitative analysis of the wear debris, and tooth surface analysis. Based on the Hertz contact theory, a dynamic model for the gear drive system was constructed, enabling the simulation and comparison of vibration acceleration signals under normal and fault conditions. The research results revealed that bearing defects induced irregularities in vibration frequency and amplitude, adversely affecting the performance and stability of the gear system. Furthermore, these defects trigger the creation of substantial wear debris, which exacerbates gear wear and reduces the gear lifespan by about 15%. Additionally, bearing defects induced intermittent load spikes and uneven stress distribution across tooth contacts, resulting in localized high shear stresses, material flaking, and surface spalling. Consequently, initial defects of the bearing will accelerate gear wear progression and lead to abnormal wear patterns, potentially resulting in the premature failure of the gear train system. The study investigates the underlying mechanisms of gear wear evolution influenced by these defects and offers practical guidelines for the engineering, manufacturing, and maintenance of gear systems.

Exploring optimal cathode composite design for high-performance all-solid-state batteries

All-solid-state batteries (ASSBs) have attracted considerable attention due to their high stability, offering a safer alternative to currently used batteries. Extensive research has been conducted to improve cathode part performance. However, the conventional hand mixing (HM) process results in inhomogeneous particle distribution, causing poor interparticle contact due to uneven stress distribution, and the solution process causes unwanted solid electrolyte (SE) deterioration when using a polar solvent although it ensures uniform SE distribution. To overcome these limitations, based on the design rule considering SE surface coverage of less than 100 %, we propose a cathode/SE composite, showing decent ionic/electronic conductivities, uniform SE distribution, and intimate interparticle contact, achievable through a mass-producible mechanical mixing (MM) process. Unlike the HM cell, the MM cell forms well-defined ionic percolating pathways and shows excellent structural stability. Consequently, the MM cell exhibits improved capacity retention during 1000 cycles and stable cyclability even under the harsh condition of 7 wt% SE. Finite element analysis theoretically demonstrates that uniform electrode and electrolyte currents are responsible for the improved performances including increased cathode utilization efficiency and reduced overpotentials. This study reveals the importance of composite design and uniform SE distribution in developing high-performance ASSBs at a practical cell level.

Effect of pillar width on the stability of the salt cavern field for energy storage

Abstract Effective planning of the cavern field involves determining the optimal pillar width between the caverns and the feasible number of caverns based on geological and mining conditions. The proper design of the pillar width is crucial to ensure the stability of the cavern field and the rational utilization of the rock salt deposit. The stability of the pillars is a complex problem influenced by various factors, including rock salt creep, changes in the cavern pressure during operational cycles, mechanical parameters, and failure criteria of the rock salt. To address this problem, the stability of the cavern field in relation to the number of caverns and pillar widths is evaluated. The evaluation is based on the following criteria: displacements, von Mises stress, strength/stress ratio, and safety factor. Three variations of pillar width and three variants of cavern fields, differing in the number of caverns, are considered. Results show that the allowable pillar width is affected by the number of caverns in the cavern field. Moreover, the stability analysis reveals uneven stress and deformation distribution in the cavern field. When the pillar width is 2.0–3.0 times the diameter of a cavern, pillars at the centre exhibit poorer stability than those at the edges of the cavern field. However, with a narrower pillar width, the highest displacements occur at the field's edges. The findings of this study provide a valuable date in the planning, design, and operation of new cavern fields for the underground storage of energy sources such as oil, natural gas, hydrogen, and compressed air in rock salt deposits.

Fatigue life prediction of corroded hangers with parallel steel wire in a network arch bridge under vehicle-bridge interaction based on a novel noniterative simplified method

Fatigue damage is a main concern during the life-cycle maintenance of bridges with corroded hangers under vehicle-bridge interaction (VBI). In this study, a novel noniterative simplified method for VBI is proposed to analyze the responses of hangers in a network arch bridge, considering the effects of vehicle types, driving lanes, and road surface roughness. Furthermore, the fatigue life of corroded hangers is investigated, considering the actual traffic flow and uneven distribution of stress in the hanger’s cross-section. The results show that longitudinal and transverse bending moments of the hanger significantly affect the stress of steel wires in one hanger but have limited influence on stress amplitudes. The fatigue lives of steel wires are considerably reduced when subjected to both uniform and pitting corrosion. The fatigue life of steel wires is reduced under deteriorating road surface conditions. Moreover, as the fatigue life of steel wires in the hangers declines, the variations in fatigue life among individual steel wires within a single hanger gradually decrease. Consequently, this trend leads to a heightened likelihood of continuous wire breakage.

Influence of filling materials on mechanical properties of fissured sandstone treated by tailings water

Fissured rocks deteriorate with increasing water content, and the mechanical behavior is significantly influenced by the filling materials within their fissures. Understanding the effects of tailings water on the mechanical properties and failure modes of rocks under different filling conditions is crucial for assessing the stability of tailings ponds. In this study, uniaxial compression tests were conducted on single-fissured sandstone filled with gypsum, cement, and epoxy resin at various immersion heights, and acoustic emission signals were monitored. The results indicate that the mechanical properties of sandstone deteriorate significantly upon immersion, but the rate of deterioration decreases with increasing immersion height. The use of stronger and more cohesive filling materials can improve the mechanical properties of fissured sandstone, but there remains a gap compared to intact samples. Differences in physical properties and uneven stress distribution between immersed and dry portions lead to the formation of complex crack networks in partially immersed samples. The strong bonding between epoxy resin and sandstone results in local stress exceeding the sandstone's bearing limit, leading to increased fragmentation. The acoustic emission activity generally exhibits a pattern of gradual increase, quiescence, and then activation. As the immersion height increases, the number of acoustic emission events and energy release decrease. The average frequency and rise angle analysis reveals that tensile cracks dominate the failure process. Near failure, the b-value drops sharply and exhibits intense fluctuations, accompanied by the emergence of numerous high-frequency signals. These phenomena provide a basis for predicting rock instability and failure.

The Effect of the Barrier Layer on the Uniformity of the Transport Characteristics of AlGaN/GaN Heterostructures on HR-Si(111).

The high transport characteristics of AlGaN/GaN heterostructures are critical components for high-performance electronic and radio-frequency (RF) devices. We report the transport characteristics of AlGaN/GaN heterostructures grown on a high-resistivity (HR) Si(111) substrate, which are unevenly distributed in the central and edge regions of the wafer. The relationship between the composition, stress, and polarization effects was discussed, and the main factors affecting the concentration and mobility of two-dimensional electron gas (2DEG) were clarified. We further demonstrated that the mechanism of changes in polarization intensity and scattering originates from the uneven distribution of Al composition and stress in the AlGaN barrier layer during the growth process. Furthermore, our results provide an important guide on the significance of accomplishing 6 inch AlGaN/GaN HEMT with excellent properties for RF applications.

Reconciling mechanical models of caldera ring-fault nucleation within the transcrustal magmatic system paradigm

The formation of a collapse caldera requires the nucleation of circumferential ring-faults that connect an underlying magma chamber with the Earth's surface. The roof of the magma chamber collapses as a consequence of magma withdrawal due to either over- or under-pressure within the chamber. Recent inferences have suggested that calderas may form atop complex transcrustal magma systems with several individual or interconnected magma chambers residing at depth throughout the crust. Whilst there have been several attempts to define the mechanical conditions leading to caldera fault nucleation, the assumptions for these models often rely on a single shallow magma chamber or the combination of a single shallow magma chamber with doming of a deep-seated magma reservoir. There have, so far, been no attempts to reconcile the mechanical conditions leading to ring-fault nucleation and potential collapse caldera formation with inferred geometries and arrangements of complex transcrustal magmatic systems. Here we address this issue using Finite Element Method (FEM) to reconcile mechanical conditions for caldera ring-fault nucleation within the transcrustal magma system paradigm by modeling multiple magma pocket arrangements. Out of the 150 distinct combinations of shallow magma chambers and pressure conditions that were tested, only 15% yielded the necessary conditions for the successful formation of a caldera ring-fault, supporting the need for special or very specific conditions for the occurrence of calderas in nature. Results show that relatively small lateral distances in the position between magma chambers inhibit the stress conditions required for caldera fault nucleation and propagation. Changes in the vertical spacing between stacked magma chambers do not significantly alter the distribution of either tensile or shear stress. This implies that the specified criteria for initiating ring-faults are consistently met, regardless of the number or arrangement of magma chambers. However, vertical offsets between laterally distributed magma compartments lead to an uneven distribution of shear stress, potentially triggering a trapdoor-type collapse. Consistent with the results presented here, the concept of vertically stacked magma compartments has been proposed as an explanation for both contemporary and ancient volcanic systems.

Effect of time-varying friction coefficient on self-excited vibration of floating spline-rotor system

Different lubrication states seriously affect the stability and safety of the aviation power transmission system. This study investigates how time-varying friction coefficients impact the stability of an aviation spline-rotor system using a spline-rotor model that considers uneven stress distribution on the tooth surface. Experimental tests with a high-frequency friction and wear test machine yield time-varying friction coefficients for splines with different lubrication, surface roughness, and materials. A sharp change of friction coefficient for the sample occurs under wear debris lubrication. The average friction coefficient for the sample with roughness 1.6 is lower than those with roughness 0.8 and 3.2. Under the same lubrication conditions, the friction coefficient of Resin matrix composites is smaller than that of metallic materials. Dynamic simulation of the spline-rotor model considering time-varying friction coefficients shows rich self-excited vibration behaviors influenced by lubrication, surface roughness, and materials.

Analysis of the effect of the direction of reinforcement of a fibrous composite material on the inhomogeneity of localization of deformations and stresses using the method of thermoelastic response

The purpose of the article is to study the effect of the direction of reinforcement of a composite material relative to the cyclic load on the inhomogeneity of stress distribution by the thermal method of non-destructive testing using the thermoelastic effect. This method is widely used in all industries for the control of structural elements and in research work. The degree of stress inhomogeneity is used when choosing the safety factors necessary to ensure the safety of technical objects. In this study, the thermoelastic effect is used to show the possibility of estimating the local distribution of stresses using the temperature field of the test object, proceeding from the linear relation between the temperature of the elastic body and mechanical stresses. The results of studying composite laminates (fibrous filler (fiberglass) with an epoxy matrix) with different laying of fibers with respect to the direction of loading are presented. Four laminate samples were considered: single-layer [0] and [90], three-layer [0]3 and [90]3. Statistical data and estimates of the coefficients of variation, methods of clustering and averaging over the length of the laminates the values of the temperature distribution over the surface of the laminates. The numerical characteristics of the distribution of local temperatures are obtained. It is shown that a more uniform distribution occurs when reinforcing is directed along the direction of the material loading. The integral and local characteristics of the temperature distribution in the samples are compared. The differences in the local temperature distribution depending on the laminate thickness were noted visually for single-layer and three-layer samples. A more uniform distribution of the load is also observed in the direction of reinforcement and with an increase in the number of reinforcement layers. The results obtained lead to the conclusion that the choice of the value of the safety factor, which evaluates the level of stress inhomogeneity, depends on the design features of the laminates. During operation of products made of composite materials in the presence of significant accumulated damage, when the uneven distribution of stresses increases, the levels of safety factors should be adjusted.