Internal Angle Research Articles

Cone-beam computed tomographic evaluation of styloid process: a retrospective study of 498 patients with maxillofacial diseases

PurposeThe purpose of this study was to assess the structural characteristics of the styloid process (SP) using cone-beam computed tomography (CBCT) examination in patients with maxillofacial diseases. The study aimed to determine the prevalence of elongated styloid process (ESP) and its relationship to gender in the study population. Radiographic records of 498 subjects were evaluated retrospectively. Radiological examinations including measurements of the structure, length, volume, and angulations of styloid process were performed on CBCT images. Males had significantly longer styloid process in both sides than females in the study population and a strong positive linear relationship was found between left and right sides’ process length (r = 0.83; p < 0.001). The mean internal oblique angle of styloid process differed between genders, but there were no statistically significant differences in the mean anterior oblique angle. Out of 498 subjects, 62 (24.13%) females and 101 (41.91%) males had elongated left styloid process (≥ 30 mm), while 75 (29.18%) and 90 (37.34%) had right side respectively.MethodsRadiographic records of 498 subjects were evaluated retrospectively. Radiological examinations including measurements of the structure, length, volume, and angulations of styloid process were performed on CBCT images.ResultsMales had significantly longer styloid process in both sides than females in the study population and a strong positive linear relationship was found between left and right sides’ process length (r = 0.83;p < 0.001). The mean internal oblique angle of styloid process differed between genders, but there were no statistically significant differences in the mean anterior oblique angle. Out of 498 subjects, 62 (24.13%) females and 101 (41.91%) males had elongated left styloid process (≥30 mm), while 75 (29.18%) and 90 (37.34%) had right side respectively.ConclusionsThis study presents the CBCT as an alternative method to CT or panoramic radiographs for the measurement and the assessment of the styloid process. Within the study in 498 subjects in China, it was observed that the males, on average, had significantly longer styloid process and narrower internal oblique angle than females either in left or right side. Around 33% of the study population had ESP.

Exploring the Relationship Between Foot Position and Reduced Risk of Knee-Related Injuries in Side-Cutting Movements

Background: Knee-related injuries often result from poor movement patterns that destabilize the joint and increase stress on knee structures. Understanding the influence of foot positioning on knee biomechanics is critical for identifying high-risk movement patterns and preventing injuries. Methods: Twenty healthy male participants performed side-cutting movements at three different foot progression angles. One participant’s data were used to develop and validate a knee finite element model with high-speed dual fluoroscopic imaging (DFIS). Combined with a musculoskeletal analysis, the model simulated internal knee loads under various foot-positioning conditions. Results: The analysis revealed that, as the external foot progression angle increased, the ankle plantarflexion decreased, while the ankle internal rotation and knee valgus moments increased. Higher stress concentrations were observed on the ACL, lateral meniscus, lateral tibial cartilage, and medial collateral ligament, particularly at the femoral–tibial ACL attachments. Conclusion: The findings suggest that a toe-out foot position elevates the risk of knee injuries by increasing stress on key structures, whereas a toe-in position may enhance joint stability, reduce the ACL injury risk, and promote favorable muscle activation patterns.

Effect of Loading Angles on Abutment Screw Loosening: InVitro Study.

Biomechanical performance is a critical factor in the long-term success of dental implants, with abutment screw loosening being a common clinical issue. This study aimed to examine the impact of abutment screw design and external load loading angles on abutment screw loosening. Abutments and abutment screws with 30°, 60°, 90°, and 180° fitting tapers were fabricated and tested for preload and initial loosening torque. Subsequently, dynamic loosening tests were conducted at loading angles of 15°, 30°, and 45°. Finite element analysis (FEA) was used to calculate the stress and strain distribution of the abutment screws. The findings indicated that large-taper abutment screws exhibit a higher preload, whereas small-taper abutment screws demonstrate greater loosening torque values. Additionally, as the loading angle increases, the loosening torque value decreases, and the stress and strain values of the abutment screw increase. Abutment screws with smaller taper heads exhibited superior resistance to loosening. Moreover, the anti-loosening performance of the abutment screws decreased with higher external load loading angles.

Behavior of TE and TM propagation modes in nanomaterial graphene using asymmetric slab waveguide

Abstract In this article, the conduction of transverse electric/transverse magnetic (TE/TM) propagation modes in nanomaterial graphene utilization of asymmetric dielectric slab waveguide was studied in terms of their applicability in optical fiber communication. Nano-graphene film was deposited on silica substrate and air cladding. Three layers were exposed to electromagnetic waves with a 1.55 µm wavelength and 1 µm thick nanographene film, silica, and air covering to study the performance and optical properties of graphene nanomaterials. The models were influenced by factors such as attenuation wavenumbers, cut-off frequency, mode number, propagation wavenumbers, skin depth, and angles of total internal reflection. The impact of these parameters was assessed through numerical analysis, revealing significant correlations. The modes generated ten numbers of TE and nine numbers of TM mode dependent upon the structure of nanographene, with low loss propagation wavenumber. As the TE/TM modes increase, the decay wavenumbers of the cladding and substrate parameters diminish. This indicates that the magnetic and electric fields undergo extremely rapid decay beyond the film region, which leads to the skin depth for higher TE/TM modes traveling longer distances in the cladding and substrate than do lower-order modes. Therefore, nanographene exhibits good optical properties due to its low absorption loss. The angles of internal reflection are greater in magnitude than the substrate and cladding key angles. Still, in the tenth TE mode, the internal reflection angles are extremely close to the critical angle as a result of the small substrate decay parameter and the near operating frequency. The tenth TE mode is weakly characterized. The characteristics of TE/TM modes in an asymmetric three-layer slab waveguide structure are realized for various mode orders and various parameters of nanographene material. The field profiles of the TE/TM modes are submitted to comprehend these characteristics.

Additive effect of glenohumeral joint hydrodilatation applied in addition to suprascapular nerve blockage in patients with adhesive capsulitis

BackgroundWe aimed to investigate the efficacy of shoulder hydrodilatation (HD) applied in addition to suprascapular nerve blockage (SSNB) on severity of pain, shoulder joint range of motion (ROM), functional status, handgrip (HG) strength in patients with adhesive capsulitis (AC).MethodsForty-eight patients who were diagnosed with AC based on physical examination findings included in the study. The patients were randomized into two groups as combination of SSNB + HD and SSNB alone. Injections were performed under ultrasonography guidance.Shoulder ROM angles were measured with a goniometer. Pain intensity was evaluated with visual analog scale. Functional status was evaluated with Quick Disability of Arm, Shoulder, and Hand (QDASH). HG strength was measured by a Jamar dynometer. After the injection, a home-based exercise program was given to all patients. Patients were evaluated at baseline, 1st and 3rd month.ResultsAbduction and external rotation ROM angles were statistically significantly limited in SSNB group, at baseline (p = 0.020, p = 0.018, respectively). In terms of other parameters, both groups were similar at baseline (p > 0.05). At comparison of baseline-1st month, a significant improvement was observed in VAS score, abduction and flexion ROM and QDASH score, in both groups (p < 0.05), however, there was no statistically significant difference between the groups. There is a statistically significant decrease in VAS score in both groups, at all times, but, no significant difference between the groups. At the comparison of baseline-3rd month measurements, it was observed that all of the parameters significantly improved in both groups, and there was no statistically significant difference between the groups except for abduction and external rotation ROM (p > 0.05). Abduction ROM and external rotation ROM were significantly higher in the SSNB group than SSNB + HD group at 3rd month.ConclusionsBoth SSNB + HD and SSNB alone provide significant improvement clinically especially in shoulder pain. HD added to SSNB does not seem to provide any additional benefit. SSNB is an effective treatment option for up to 3 months in patients with AC, mainly in abduction and external rotation limitation.

Distortions in Classical Mechanics as a Consequence of Euclidean Geometry Utilization

We live on a huge sphere. When the sum of interior angles in a triangle is greater than [Formula: see text] and each point has a different local vertical, we must use spherical geometry. Euclidean and non-Euclidean geometries are non-equivalent systems, with their own premises and completely different foundations. The use of any logic and tool from orthogonal into non-orthogonal realities (and vice versa), leads to big errors. Newtonian concepts are treated as absolutes in classical mechanics. Content analysis shows that even recent physics publications have inadmissible distortions in the description of natural phenomena in the domain of classical mechanics, inherited through the utilization of the Euclidean model. The whole objective reality has been presented using the tools of Euclidean geometry. When we use the tools of spherical geometry to examine the same phenomena, we get very different findings. The Law of conservation of energy appears as the most efficient tool for the evaluation of these significantly different findings. It confirms the validity of the new discoveries presented in this paper and gives legitimacy to the whole project! Classical mechanics becomes more consistent with the conservation laws of Physics, and the subject’s coherence is lifted to a significantly higher level.

Graded metastructure design for linearly auxetic deformation under tension: From 2D honeycombs to 3D truncated cones

Mechanical metamaterials exhibit special properties that cannot be realized in traditional materials. To enable a metamaterial with a sequential Poisson’s ratio and controllable expansion, a 2D-graded hybrid re-entrant honeycomb is designed in this work by coupling graded re-entrant unit cells with negative and positive Poisson’s ratios. The correlation between Poisson’s ratio and structural location under tension is studied by finite element analysis and experiments. The influence of microstructural parameters, including base angle, height ratio, and internal angle, on the relationship between the Poisson’s ratio and structural location is systematically analyzed. The theoretical analysis shows that the 2D-graded hybrid metastructures exhibit auxetic behavior with a linearly declined Poisson’s ratio along the tensile direction due to the introduction of a height ratio, resulting in gradual expansion and elongation. Furthermore, adjusting the variation of internal angles at a small height ratio can enhance the negative Poisson’s ratio of the 2D-graded hybrid re-entrant honeycomb. Finally, a 3D-graded conical metastructure exhibiting linear auxeticity is constructed based on the 2D-graded lattice. Considering their designed linearity of deformation under tension, the 2D- and 3D-graded metastructures can facilitate the design of conical profiles for an extendable rocket nozzle and other deployable devices.

Single‐Mode Lasing by Selective Mode Structure Breaking

AbstractSingle‐mode lasers are highly desirable for applications in optical communication, quantum information, and photonic computing, but their realization is challenging due to the competition of multiple closely spaced resonant modes in microcavities. This paper proposes a novel approach, termed mode structure breaking, to achieve high‐performance single‐mode lasing in an individual laser cavity. By introducing selective spatial structure defects, the mode structure of competing modes can be broken, enabling single‐mode selection without huge losses. As proof of concept, femtosecond (fs)‐laser ablation is experimentally employed to introduce external angle defects on a microdisk cavity, effectively eliminating mismatched competing modes and thus achieving single‐mode lasing output. The lasing characteristics are further optimized by incorporating a punched hole to suppress remaining high‐order lasing modes. Notably, the fabricated perovskite laser sources, which are called mode‐structure‐breaking lasers, demonstrate excellent single‐mode lasing properties, including stability, an ultralow threshold (≈2.31 µJ cm−2), and a narrow linewidth (≈0.15 nm). Conclusively, this comprehensive study of manipulating lasing mode by breaking mode structure may provide a promising approach to realizing single‐mode lasing in a single structure, which is significant for producing on‐chip laser source arrays for use in photonic integrated circuits.

A Triangular Structure Constraint for Pedestrian Positioning with Inertial Sensors Mounted on Foot and Shank

To suppress pedestrian positioning drift, a velocity constraint commonly known as zero-velocity update (ZUPT) is widely used. However, it cannot correct the error in the non-zero velocity interval (non-ZVI) or observe heading errors. In addition, the positioning accuracy will be further affected when a velocity error occurs in the ZVI (e.g., foot tremble). In this study, the foot, ankle, and shank were regarded as a triangular structure. Consequently, an angle constraint was established by utilizing the sum of the internal angles. Moreover, in contrast to the traditional ZUPT algorithm, a velocity constraint method combined with Coriolis theorem was constructed. Magnetometer measurements were used to correct heading. Three groups of experiments with different trajectories were carried out. The ZUPT method of the single inertial measurement unit (IMU) and the distance constraint method of dual IMUs were employed for comparisons. The experimental results showed that the proposed method had high accuracy in positioning. Furthermore, the constraints built by the lower limb structure were applied to the whole gait cycle (ZVI and non-ZVI).

Geodesic loops on tetrahedra in spaces of constant sectional curvature

AbstractGeodesic loops on tetrahedra were studied only for the Euclidean space and it was known that there are no simple geodesic loops on regular tetrahedra. Here we prove that: 1) In the spherical space, there are no simple geodesic loops on tetrahedra with internal angles $$\pi/3 &lt; a_i&lt;\pi/2$$ π / 3 &lt; a i &lt; π / 2 or regular tetrahedra with $$a_i=\pi/2$$ a i = π / 2 , and there are three simple geodesic loops for each vertex of a tetrahedra with $$a_i &gt; \pi/2$$ a i &gt; π / 2 and the lengths of the edges $$a_i&gt;\pi/2$$ a i &gt; π / 2 . 2) We obtain also a new theorem on simple closed geodesics: If the angles $$a_i$$ a i of the faces of a tetraedron satisfy $$\pi/3 &lt; a_i&lt;\pi/2$$ π / 3 &lt; a i &lt; π / 2 and all faces of the tetrahedron are congruent, then there exist at least $$3$$ 3 simple closed geodesics. 3) In the hyperbolic space, for every regular tetrahedron $$T$$ T and every pair of coprime numbers $$(p,q)$$ ( p , q ) , there is one simple geodesic loop of type $$(p,q)$$ ( p , q ) through every vertex of $$T$$ T . The geodesic loops that we have found on the tetrahedra in the hyperbolic space are also quasi-geodesics.

Metallic Metamaterials with Auxetic Properties: Re-Entrant Structures

The present article is an exploration of metamaterial structures exhibiting auxetic properties. The study shows the effect of three geometric parameters of re-entrant auxetic cells, namely, the internal initial cell angle (θ0), the strut length ratio h/l, and the degree of opening of the unit cells expressed by the change in the Δθ angle, on the value of the Poisson’s ratio. It combines theoretical insights into physical re-entrant auxetic structures with the demonstration of structures that can be subjected to cyclic loading without being damaged. The experimental section features the results of the compression tests of a symmetrical structure made up of four re-entrant cells and tensile tests of a flat mesh structure of size 4 × 4. In the mesh structure, a modification was applied to the re-entrant cells, creating arched strut connections. It was shown that the value of the maximum load for such structures depends on the bending angle and the length of the inclined strut. The mesh structure was created using torsion springs. Its cyclic tension for different amplitudes yielded Poisson’s ratio values in the range of −1.4 to −1.7. These modifications have enabled stable, elastic, and failure-free cyclical changes of the structure’s dimensions under load.

The effect of manipulation under anesthesia on knee kinematics in individuals with arthrofibrosis after anterior cruciate ligament reconstruction.

Manipulation under anesthesia (MUA) has been recommended for refractory arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. However, the effectiveness of MUA to restore normal kinematics of the arthrofibrotic knee is still unclear. The objective of this study was to evaluate tibiofemoral and patellofemoral kinematics in six degrees-of-freedom (6DOF) in patients with arthrofibrosis before and after MUA. Computed tomography and dual fluoroscopic imaging system were used to assess in vivo knee kinematics. Ten patients (6 women and 4 men; 32.6 ± 6.5y, 168.4 ± 7.8cm, 61.8 ± 13.2kg) were included in this study. The tibiofemoral and patellofemoral kinematics in 6DOF were collected before and one year after MUA. A simple analysis of variance was used to evaluate kinematic data of preoperative arthrofibrotic knee, postoperative arthrofibrotic knee, and the contralateral knee. The patella in the postoperative arthrofibrotic knee shifted significantly more inferiorly compared to the preoperative knee at 45° (P = 0.010), 60° (P = 0.008), and 75° (P = 0.049) of flexion. The patellar flexion in the postoperative arthrofibrotic knee significantly increased at 45° (P = 0.048), 60° (P = 0.037), and 75° (P = 0.006) of flexion compared to the preoperative arthrofibrotic knee. The patellar tilt was significantly decreased at 60° (P = 0.006) and at 75° (P = 0.037) of knee flexion in the postoperative arthrofibrotic knee compared to the contralateral knee. MUA significantly increased tibial internal rotation angle in the arthrofibrotic knee at 45° (P = 0.047), at 60° (P = 0.033), and at 75° (P = 0.021) of knee flexion. MUA could restore normal patellar inferior shift, flexion, and tibial rotation compared to the contralateral side. However, the MUA could not restore normal patellar tilt of the arthrofibrotic knee. This indicated that improvement of patellar tilt should be emphasized in postoperative rehabilitation.

Shear behavior of cold region clay-concrete interface under temperature-controlled direct shear tests

The shear properties of the permafrost-structure interface play a crucial role in analyzing the performance of engineering structures in cold regions. Direct shear tests were carried out on the permafrost-concrete structural interface by means of self-improved and optimized temperature-controlled direct shear apparatus to investigate the effects of temperature, moisture content and freeze-thaw cycles. Test results were used to establish a shear characteristic model under coupled influence of temperature and humidity. Preparation of specimens consisting of precast C30 concrete blocks and soil samples taken from borehole cores of the pile foundation of the Middle Bridge No. 3 on the road from Sai Township to Qiuluo Village, Sakya County, Tibet, China, and were treated to different effective confining pressure (σn = 300 kPa, 400 kPa, 500 kPa and 600 kPa), different temperatures (T = −20 °C, −15 °C, −5 °C, 0 °C, 5 °C, 15 °C, and 20 °C), different moisture contents (ω = 5 %, 10 %, 15 %, and 20 %), and different numbers of freeze-thaw cycles (N = 0, 1, 3, 5, 7and11) from −15 °C to 15 °C, test results are given and analyzed. The peak shear stress (τp) is significantly higher than the residual stress (τr) at negative temperature, τp is greater than 1.5 times to 3.2 times of τr. τp is greatly affected by temperature changes, τp under negative temperature is 17 % higher than that under positive temperature, because the water in the soil freezes at negative temperatures, forming a concrete-ice-soil bond interface, which increases the peak strength of the interface. While τr is insensitive to temperature changes. At negative temperatures, the cohesion (c') changes less with increasing water content (ω), and the effect of ω on the external friction angle (φ′) is more significant. At positive temperature, the cohesion decreases with increasing ω, and the effect of ω on the external friction angle is not significant. When N < 5, the cohesion increases with the increase of N; when N = 5, c' reaches the maximum value; when N > 5, c' decreases with the increase of N. Moreover, regardless of the type of shear behavior, the first five freeze-thaw cycles have the greatest impact on the external friction angle. Compared with the sample that has not experienced freeze-thaw cycles, when N = 5, the total decrease in the external friction angle of the sample is 25.6 %.

Analysis of changes in lower limb joints of athletes during the movement of wild horses’ mane parting based on biomechanics

In the era of fitness, more and more young people are familiar with Taijiquan, a kind of physical fitness exercise. By conducting biomechanical analyses of the movements of Taijiquan, it is possible to exercise the body better. Numerous techniques in Taijiquan make it difficult to study each individually. Therefore, this paper studied the movement of “wild horses’ mane parting” in terms of biomechanics by analyzing the joint angle, stiffness, and impulse during this movement. Twenty male athletes were selected as subjects and divided into a professional group and a beginner group according to their training periods. High-speed cameras were used to shoot the “wild horses’ mane parting” movement. The angles of lower limb joints in these athletes were measured to calculate joint impulse and stiffness. The results showed that, compared with the professional group, there were significant differences in the adduction and abduction angle and the internal and external rotation angle between the beginner group and the professional group in the single-leg support movement stage (P&lt; 0.05). There were also significant differences in joint impulse and stiffness (P&lt; 0.05). Compared with beginners, long-term professional practitioners can make their movements more standardized. By comparing movements and data analysis, beginners can make their movements more standardized when practicing Taijiquan and avoid the risk of sports injury. The novelty of this article lies in the use of high-speed cameras to capture athletes’ movements, enabling accurate analyses of their joints and providing effective references for precise training.

Effect of admixed silicone emulsion on water and chloride transport properties of concrete

The addition of silicone is effective method for improving both surface and internal hydrophobicity of concrete, thus clarifying its effect on transport property of concrete is very important. In this study, both water and chloride transport properties of concrete incorporated with three silicone emulsions based on different active ingredients (silane oligomers or silane monomers) were evaluated and investigated. The results show that all three silicone emulsions exhibit no obvious negative effect on hydration and microstructure of cement paste; however, the admixed silicone emulsions increase both the thickness and porosity of ITZ in concrete. Therefore, the admixed silicone emulsions result in reduced compressive strength of concrete. Further, the incorporated silicone emulsions efficiently increase surface and internal water contact angle of concrete, thus mitigating both water absorption and chloride transport in concrete. Due to more pronounced interaction between silane oligomers and hydration products based on molecular dynamics simulation, the beneficial effect on improving hydrophobicity of concrete and halting water and chloride transport is more significant for the admixed silicone emulsion with silane oligomers as active ingredient.

Improvement of hydrogen reciprocating compressor efficiency: A novel capacity control system and its multi-objective optimization

To enhance the operational efficiency of hydrogen compressors and reduce the costs associated with the storage and transportation of hydrogen, this paper has developed a novel capacity control system (CCS). This system ensures that the compressor accurately compresses hydrogen according to actual demand, driven by an electromagnetic actuator, which simplifies the system design and enhances operational precision. To optimize the system's performance, a multi-objective optimization was conducted. Initially, a hydrogen compressor backflow working model and a comprehensive evaluation index system were established. Subsequently, a three-tier computational multi-objective optimization framework was proposed based on the working model, ultimately determining the optimal combination of key system parameters. A prototype was manufactured and subjected to validation testing and a full life cycle analysis. The results indicate that the developed system can accurately regulate the amount of compressed hydrogen within a range of 0%–100% load. Compared to traditional systems, for the same compressor group, carbon emissions and costs were reduced by 41.93% and 36.49%, respectively. The optimized design of the internal and external resistance angles and the limiter plate thickness are 11°, 16°, and 1 mm, respectively. Compared to the baseline state, the specific energy consumption of the hydrogen compressor per unit of exhaust volume has been reduced by 28.22%. Additionally, during the ejection and retraction processes of the actuator, the peak vibration impact on the hydrogen compressor has been reduced by 77.6% and 73.3%, respectively, achieving optimal comprehensive performance.

Flexural behaviors of asymmetric Re-entrant auxetic honeycombs

A family of negative Poisson's ratio honeycombs with asymmetric base units and potential applications in civil and marine industries are introduced by introducing asymmetricities to the geometry of regular re-entrant unit cell. These structures, namely the single symmetry-broken re-entrant (SSR), double symmetry-broken re-entrant (DSR), and hybrid symmetry-broken re-entrant (HSR) honeycomb lattices, are fabricated through fused filament fabrication and subjected to experimental three-point bending (TPB) experiments and simulations. The novel designs showcase exceptional specific energy absorption (SEA) attributes compared to the regular metamaterial, with the SSR structure exhibiting a remarkable 147.2% higher SEA. The asymmetric metamaterials also demonstrate higher flexural modulus (Ef) compared to the benchmark design, with the SSR and DSR models boasting approximately 29% and 19% higher Ef, respectively. Studies on design parameters show that internal angle of unit cells that creates the asymmetricity affects the flexural performance of the unique auxetic honeycombs, significantly. Finally, parametric investigation on out-of-plane bending of the honeycombs showed the dominance of all asymmetric-unit honeycombs over the benchmark due to having organized self-contact regions. The SSR and DSR structures own about 51% and 39% higher SEA than the benchmark honeycomb under out-of-plane TPB, respectively.

A Modified Reentrant Metamaterial with Equal and Enhanced Orthogonal Elastic Properties

Herein, an improved mechanical metamaterial is proposed, which is derived from the decomposition, rotation, and reassembly of reentrant structures. The structure is parametric, allowing for rapid redesign. The study focuses on the variations in equivalent stiffness and Poisson's ratio of the structure within the linear elastic range when internal rib angle θ changes. First, based on homogenization simulation analyses, it has been verified that this design achieves the tailorable equivalent elastic modulus and Poisson's ratio over a wide range, meanwhile, maintaining equal elastic properties in the orthogonal direction at all times. Second, to reduce future repetitive experiments, an interpolation model is established to expand the design domain. The fitting formula indicates that by modifying θ and relative wall thickness t/L0, the elastic performance of the structures can be tailored. Additionally, the impact of boundary conditions is discussed to minimize experimental costs. Finally, the accuracy of the simulations is validated through uniaxial compression tests.

A new calculation method for the response of active-passive bridge piles considering pile-soil interface friction

The pile foundation of bridges under unregulated surcharge loads experiences a complex force pattern, which is subject to active loads and passive loads. In this paper, a more comprehensive calculation method for the response of active-passive piles was proposed, which considered the effect of pile-soil interface friction and soil stress states on the passive loads. First, the Ito theory was improved by adopting the adhesion c a and external friction angle φ a to characterize the pile-soil interface friction. Then, the soil around the pile in elastic, elastoplastic, and plastic flow states was considered to calculate the variation of the passive load. Finally, a nonlinear p-y curve was introduced to establish the calculation model of active-passive piles, and the finite difference program CPAPP was prepared for the solution. The results show that the pile response calculated by CPAPP is consistent with the field measurement, indicating that the proposed calculation method has high accuracy. When the soil is in an elastic state, the pile-soil interface friction does not affect the passive load. When the soil is in a plastic state, the passive load is closely related to soil strength parameters and pile-soil interface friction parameters.

Buckling analysis and parametric optimization of the metal-composite shell with voids under hydraulic pressure combined with sensitivity analysis

Structural design parameters always impact the buckling properties of the composite shells due to the differences in the anisotropy of the materials and the varying enhancement capabilities of each component. This paper aims to analyze the parametric effect on the buckling load and optimize the design parameters of metal-composite shells with voids under hydraulic pressure. Firstly, the theoretical model of buckling load is established based on the microscopic model of hybrid materials and the Galerkin method. Then, four design parameters including fiber volume content, winding angles, and CNTs volume content are selected to discuss the parametric effect on the critical buckling load. Further, the global sensitivity analysis is conducted to determine the influence rank, and the GA-PSO algorithm is used to confirm the optimal parametric combination. The results imply that the fiber volume content and internal and external helical symmetrical angles significantly affect the buckling load. Besides, The winding layers of internal and external helical symmetrical angles enhance the hydraulic resistance of the anti-symmetric structure. The middle helical layer can be influenced by the outer layer, leading to directional changes in the critical buckling load at an angle of around 50°.