Large Plastic Research Articles

Thermal ratcheting of uranium simulated with a thermo-elasto-visco-plastic self-consistent polycrystal model

Uranium polycrystal aggregates accumulate large plastic deformation during thermal cycling in a process known as thermal ratcheting. This process is induced by highly anisotropic single crystal properties, texture, and a complex coupling between thermal, elastic, and plastic mechanisms of deformation. In this study, a thermo-elasto-visco-plastic polycrystal model is developed and applied to the prediction of thermal ratcheting in uranium. The model is based on the evolution of dislocation density on individual slip systems and accounts for static recovery effects. The model captures the plastic relaxation of intergranular stresses induced by thermal cycling and leads to quantitative understanding of the coupling between thermal, elastic and plastic mechanisms, and the important role played by static dislocation recovery in uranium. Results are compared with thermal ratcheting measurements.

Feasibility Study of Single-Point Incremental Forming for Discontinuous-Fiber CFRP Using Oil-Bath Heating

Although, three-dimensional printing has several advantages, however there are currently many limitations. In particular, printed products using composite materials such as fiber-reinforced plastic have yet to achieve the same mechanical properties as those obtained from conventional manufacturing methods. In addition, fabricating thin plates or thin shell shapes with sufficient strength is challenging. Incremental forming enables high-mix, low-volume production of thin sheets. This method applies incremental deformation to thin sheets, the desired shape is obtained by accumulating the deformation, and no dies are required. Carbon-fiber-reinforced plastic (CFRP) materials have high specific strength. Discontinuous-fiber CFRP is capable of large plastic deformation under appropriate conditions due to the discontinuity of the reinforcement, and its mechanical properties are nearly isotropic due to the random fiber arrangement. The authors focused on this property and studied the application of single-point incremental forming to discontinuous carbon-fiber-reinforced polyamides. In this study, the workpiece was formed by heating it locally to a deformable temperature by the frictional heat between the rotating tool and the workpiece. The forming experiment was also conducted in an oil bath to keep the entire material at a suitable forming temperature. The results showed that the spindle speed affected forming results even in an oil bath and that heating using an oil bath suppressed deviations from the sine law for thickness and wall angle due to elastic deformation.

Evaluation of Shear-Punched Surface Layer Damage in Three Types of High-Strength TRIP-Aided Steel

The damage properties in the shear-punched surface layer, such as the strain-hardening increment, strain-induced martensite fraction, and initiated micro-crack/void characteristics at the shear and break sections, were experimentally evaluated to relate to the stretch-flangeability in three types of low-carbon high-strength TRIP-aided steel with different matrix structures. In addition, the surface layer damage properties were related to the mean normal stress developed on shear-punching and microstructural properties. The shear-punched surface damage of these steels was experimentally confirmed to be produced under the mean normal stress of negative to 0 MPa. TRIP-aided bainitic ferrite (TBF) steel had the smallest surface layer damage, featuring a significantly suppressed micro-crack/void initiation. This was due to the fine bainitic ferrite lath matrix structure, a low strength ratio of the second phase to the matrix structure, and the high mechanical stability of the retained austenite. On the other hand, the surface layer damage of TRIP-aided annealed martensite (TAM) steel was suppressed next to TBF steel and was smaller than that of TRIP-aided polygonal ferrite (TPF) steel. The surface layer damage was also characterized by a large plastic strain, a large amount of strain-induced martensite transformation, and a relatively suppressed micro-crack/void formation, which resulted from an annealed martensite matrix and a large quantity of retained austenite. The excellent stretch-flangeability of TBF steel might be caused by the suppressed micro-crack/void formation and high crack propagation/void connection resistance. The next high stretch-flangeability of TAM steel was associated with a small-sized micro-crack/void initiation and high crack growth/void connection resistance.

Geometrically exact 3D beam theory with embedded strong discontinuities for modeling of localized failure in bending

In this work, we propose the elastoplastic model of a three-dimensional (3D) geometrically exact beam, which can capture localized bending deformation leading to a plastic hinge. This is a follow-up work to Tojaga et al. (2023), where we only studied the fracture of fiber-like beam structures that break in mode I or mode II, here extended to handle beam-like behavior with bending failure and the main difficulty of the non-vectorial character of large 3D rotations. The Reissner model is chosen for representing the large elastic and large plastic deformations of such a beam model, which leads to the multiplicative decomposition of the rotation tensor. We shown how to replace this with the corresponding additive decomposition of the rotation vector derivatives, to be performed in the material description in the tangent space of SO(3) manifold in the initial configuration. The plasticity model for which we give a more detailed implementation employs a Rankin-like multi-surface plasticity criteria, where each moment vector component (i.e. torsion or bending) is considered separately. The non-local variational formulation is proposed to deal with the softening phenomena characteristic of localized bending failure, where the fracture energy is introduced as the main parameter for softening. The discrete approximation is built in terms of the embedded-discontinuity finite element method (ED-FEM), which introduces a jump in rotation vector that can be handled at the level of a particular beam element. This kind of approach builds upon the best approximation property of the FEM discrete approximation in the energy norm and provides the best-approximation property for the dissipated energy computations, and thus optimal computational accuracy if the quantity of interest is inelastic dissipation. The computations are carried out by the operator split method, which separates the computations of global state variables (displacements and moments) from local (plastic curvature) variables. Several illustrative examples are provided to confirm an excellent performance of the proposed methodology.

Comprehensive analysis of fused deposition modeling process conditions for enhancing mechanical properties and surface quality of 3D-Printed poly-ether-ether-ketone

Fused deposition modeling (FDM) technology is a convenient manufacturing approach for poly-ether-ether-ketone (PEEK) components. In this study, a comprehensive study of the influence of FDM process parameters on the mechanical property and surface quality of 3D-printed PEEK printed with different directions was carried out. The results show that crystallinity of PEEK materials and the pores/gaps between the printing filaments jointly affect the mechanical properties and surface quality of PEEK structural parts. Then, material-structure-property linkage mechanism was revealed. Through the research conducted, crucial processing parameters to enhance the mechanical properties and surface quality of PEEK samples was determined. High tensile strength (91.75 MPa, which was close to the performance of injection molded components) and surface quality (Ra 7.9 μm) was obtained by regulation the nozzle temperature and annealing temperature to improve the crystallinity. Meanwhile, tensile strength of z-Sample was increased from 7.36 MPa to 18.30 MPa (with an increase of 148.64%). High Young's modulus (3.09 GPa) and large plastic strain (exceed 13.91%) was achieved by regulation the nozzle temperature and printing speed to reduce the porosity between PEEK filaments.

Microplastics and Nano-plastics Contamination in Foods: Current Understanding of the Health Impact on Human and Potential Solutions

Plastics released into the environment can be degraded by physical erosion, biodegradation, photocatalytic activity, and oxidation, resulting in smaller plastics particles. Microplastics (MPs) are plastic particles relatively smaller than 5 mm in size. Furthermore, microplastics with particle sizes less than 1000 or 100 nm are known as nano-plastics (NPs). The presence and effect of MPs and NPs in human body has not been adequately studies, thus we aim to explain the origins of MPs and NPs adept, carefully explore the pathways by which MPs and NPs enter the body system and highlight the impact of MPs and NPs on human health. Major examples include Polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyamide (PA), polystyrene (PS), polyethylene terephthalate (PET), Acrylonitrile-Butadiene-Styrene (ABS), and polymethyl methacrylate (PMMA). MPs and NPs were found to have two sources (primary and secondary). The primary sources are materials purposely produced to suit household and industrial uses, such as exfoliants for skin care products, construction, and packaging materials. Secondary sources originated from the decomposition/degradation of large plastic products over time. Plastics were found in plants (fruits and vegetables), animals (fish, crab, shrimp, oysters, and mussels), water (taps, sachet, and bottled water), salt, sugar, and honey. Plastics' impact on the human ecosystem is getting increasingly severe, and it is imperative that proper attention be paid to this issue. The vast number of MPs and NPs available can influence the lives of the populace in each geographic area. In this review article, we identified three routes through which MPs and NPs gain entrance into the human body: oral ingestion, cutaneous (skin contact), and inhalation. Furthermore, we investigated and summarized the impacts of MPs and NPs on human health. The most impacted organs in the body included the lungs, blood, kidney, brain, ovary, testes, and intestines. In this review, we offered a viable solution that includes the use of biodegradable polymers, increased usage of eco-friendly biotechnology and engineering solutions, and the implementation of regulatory measures. In future, we intend to investigate the bioaccumulation and effect of MPs/NPs on human health.

Simplified analytical method for predicting the large deformation of stiffened plates with initial cracks under repeated impacts

The impact resistance capacity of structures can be affected by the formation of cracks. To address the issue of repeated impacts on structures with initial cracks, a relationship was established between cracks and the energy dissipation of stiffened plates based on rigid–plastic theory. A simplified analytical method was proposed to predict the large plastic deformation of stiffened plates with initial cracks. To verify the accuracy of the analytical method, repeated impact experiments and numerical simulations were conducted. The influences of crack length and position on the dynamic responses of stiffened plates were explored. The experimental, numerical, and analytical results were in good agreement. The research results showed that the permanent deformations of stiffened plates increases approximately linearly with increasing crack length on the outer plate. However, the influence of stiffener cracks on the permanent deformation of stiffened plates depends on whether the stiffener fractures. The influence of cracks on the load-carrying capacity of the structure is more pronounced when the crack is located in the stiffener.

Poisson’s Ratio of Selected Metallic Materials in the Elastic–Plastic Region

Poisson’s ratio is one of the fundamental characteristics in the material models that are used. In engineering practice, its values are assumed to be constant in the elastic and in the plastic region. In this paper, the conventionally used values of this number for steel materials and aluminum alloys are confronted with experimental results. By using non-contact strain measurements with the DIC (digital image correlation) method, the evolution of the Poisson ratio value in the regions of transition from the elastic to the plastic region as well as in the regions of large plastic deformations was documented. The obtained experimental results are graphically compared using the proposed strain scaling. The gradient of the Poisson ratio changes in the vicinity of the yield stress is significant, indicating the need for a refinement of the material models in this region. Deviations from the conventionally used value of this number were found in the large plastic deformation region. In conclusion, a possible approach for improving the accuracy of simulations in FEM softwares was formulated.

Elasto-plasticity theory for large plastic deformation and its use for the material stiffness determination

AbstractIn this paper, we present a finite elasto-plasticity theory for large plastic deformations. For the elastic part of the model, we use the St. Venant–Kirchhoff elasticity. The plastic part is described by the isomorphy concept, the yield condition is covered by the isotropic $$J_2$$ J 2 theory of (Huber in Czas Techn 22:34,1904; von Mises in Math Phys 4:582–592, 1913) and (Hencky in ZAMM 9:215–220, 1924), and the yield condition uses the principle of maximum plastic dissipation. The numeric of this theory is discussed and finally implemented in a Fortran code to use it as material law in the UMAT subroutine of the finite element program Abaqus. The material law is validated using different test calculations like tensile and shear tests as well as a large deformation simulation compared to the Abaqus internal material law. Further, we apply this material model to determine the effective material stiffness tetrad of large deformed inhomogeneous materials. For these purposes, we additionally present an automated method for determining material stiffnesses of an arbitrary material in Abaqus.

A new machine learning-based evaluation of ductile fracture

Ductile fracture occurs with large plastic deformation prior to fracture and is primarily characterized by voids of varying sizes. In this work, a new approach based on machine learning is proposed for the characterization of ductile fractures. The method is based on the application of a pre-processing of the fractographies, followed by a processing that includes the generation of a mask through a mathematical morphology, a classification is made according to their size in micrometers to later make a histogram of the size of the cavity in relation respect to its frequency of repetition in each fractography. Besides, the histogram is then normalized to generate a Probability Density Function (PDF). Based on the PDF, a third-order statistical metric known as Fractography Skewness (FS) is used to evaluate fracture susceptibility and is related to the Degree of Fracture Susceptibility (DFS). If the FS is negative (indicating a left-skewed PDF), the fractography is characterized by large voids and is assigned a DFS of 1, indicating low susceptibility. Conversely, a positive FS (indicating a right-skewed PDF) indicates the presence of small voids, resulting in a DFS of 3, indicating high susceptibility. The proposed quantitative methodology demonstrates a higher accuracy than the most advanced current techniques based on deep learning and the subjectivity of the specialist.

Consistent memory surface model for plateau and hardening regions

Mild steels are frequently used in building structures because of their high strength, productivity, processability, and weldability. One key feature of mild steels is their yield plateau, which is followed by a hardening region in the stress–strain relationship. During large earthquakes, building members can experience a large plastic strain whose amplitude is difficult to predict beforehand. Constitutive equations applicable to the full-range strain field are necessary for accurate structural safety evaluation. This study provides novel constitutive equations for the plateau region, capable of reproducing a yield plateau. A set of hardening constants was proposed to satisfy the consistency condition of the plastic multiplier under any loading pattern. The closed form of the stress–strain relationship was derived to calibrate the material constants. The material constants were calibrated using two types of material test results. The results of the proposed model were consistent with the material test results under cyclic loading at various strain amplitudes. This was validated by comparing the shear buckling and lateral torsional buckling test results of an H-shaped beam with the finite element analysis (FEA) results. The numerical demonstration also highlighted the significance of not only material constitutive laws but also the introduction of residual stress and initial imperfections in reproducing the pre- and post-buckling behaviors. The convergence of the residual force for the proposed model was equivalent to those of the authors’ previous model and the Chaboche model. These results indicate that the proposed model can predict hardening phenomena at the material and structural levels in the plateau and hardening regions.

Plastic anisotropy in yield stress of drawn pearlitic steels

Plastic anisotropy in the yield stress of pearlitic steels evolved by drawing was studied. The tension and compression tests were performed in parallel and perpendicular directions to the drawing direction. The yield stress in the parallel tension and vertical compression tests increased with the increase in drawing strain. On the other hand, in the parallel compression, the yield stress decreased significantly at the small drawing strain and then increased at the larger strain. The difference between the yield stress at the tension and at the compression did not change largely after the start of the drawing. The observation of microstructure indicated no significant heterogeneity of the deformation microstructure and texture at the different locations in the radial direction of the drawn samples, meaning that the plastic anisotropy was brought by reasons other than the non-uniformity of the deformation condition. The measurement of the distribution of the local misorientation in ferrite suggested the large plastic deformation even at smaller strain by drawing. This result indicates that the residual stress in plastically deformed ferrite brings back stress, which can be the source of the plastic anisotropy.

Experimental and numerical study of grooved gusset plate damper for cross-braced frames

An innovative grooved gusset plate damper (GGPD) is further developed in this study by conducting cyclic tests and numerical analysis. The proposed damper is installed in X-Concentrically Braced Frames (X-CBFs) for enhancing the seismic performance and energy dissipation of such a system. To investigate the performance characteristics of the system, three 2/3-scale specimens are constructed that are different only in the details of the damper. The damper consists of a gusset plate in which a number of slits are cut around the diagonal braces. The steel between the slits undergoes large plastic deformations under in-plane double curvature, which provides a good level of ductility and energy dissipation. Low cycle fatigue is observed at drift ratios over 1.5% in the first specimen. Thickness of the middle part of the gusset plate is increased in the third specimen as a remedy which turns out to be successful to postpone degradation of stiffness and strength to the drift ratios larger than 3%. Furthermore, a detailed nonlinear 3D finite element model is developed and validated against the results of laboratory tests. The nonlinear finite element model is shown to be successful in predicting failure and fracture due to low cycle fatigue and showing the superiority of the modified specimens in preserving the stable shapes of the hysteresis loops and the cyclic energy dissipation.

Phase‐field model for ductile fracture in the stress resultant geometrically exact shell

SummaryWe present a phase‐field fracture model for a stress resultant geometrically exact shell in finite deformation regime where the configuration manifold evolves according to deformation and fracture. The Reissner–Mindlin shell problem is first solved via the finite element method, where the independent unknown fields are the displacement and director. The phase‐field ductile fracture model is then coupled with the verified geometrically exact shell by enriching the three‐field elasto‐plastic free energy with a regularized crack surface energy. To capture the geometrical nonlinearity due to the large plastic deformation exhibited in the processing zone, the corresponding finite‐strain stress resultant elasto‐plasticity model is coupled with the phase field model. This coupling between the stress resultant elasto‐plasticity model and the phase‐field fracture model enables us to predict the different amounts of energy dissipation attributed to plastic deformation and fracture and hence simulate the crack propagation in the ductile regime properly. We introduce a mixed finite element model with displacement, director, and phase‐field order parameters as the nodal degree of freedoms formulated on the mid‐surface. An energy‐based arc‐length method is generalized to track the equilibrium path and mitigate instabilities arising from material nonlinearity. Four numerical examples are presented to validate the implementation of the model and demonstrate its capability to simulate ductile fracture in shell structures. These examples include a plane‐stress tension/shear fracture model, the Muscat‐Fenech and Atkins plate, axial tension of a notched cylindrical shell, and ductile fracture of a simply supported plate under uniform pressure.

Fatigue and Impact Behavior of Friction Stir Processed Dual-Phase (DP600) Steel Sheets

This study investigates the impact of friction stir processing (FSP) on the deformation behavior of 1.1 mm-thick DP600 steel sheets under both static and dynamic loading scenarios, with a focus on the automotive applications of the material. During the process, the large plastic shear strains imposed by FSP resulted in a maximum temperature of 915 °C, leading to a morphological transformation of the martensite phase from well-dispersed fine particles into lath martensite and grain refinement of the ferrite phase. DP600 steel showed an almost two-fold increase in static strength parameters such as the hardness value, yield strength, and ultimate tensile strength. As-received and processed DP600 steel exhibited a plastic deformation behavior governed by strain hardening. However, uniform elongation and elongation to failure after FSP took lower values compared to those of the as-received counterpart. Following the improvement in the static strength of the steel, the fatigue strength of the steel increased from 360 MPa to 440 MPa after the FSP. The finite-life fatigue fracture surfaces of the as-received samples were characterized by the formation of fine bulges due to the variation in the crack propagation path in the vicinity of the martensite particles/clusters. After FSP, the transformation of the martensite particles into coarser lath martensite also transformed the fracture surface into a step-like morphology. The microstructural evolution after FSP caused a decrease in the absorbed impact energy and maximum striker reaction force from 239 J and 37.6 kN down to 183 J and 33.6 kN, respectively. However, the energy absorption capacity of the processed steel up to failure was higher than the absorbed energy value of the as-received steel at the same impact displacement. The simultaneous decrease in both impact energy and reaction force is attributed to the higher cracking tendency of the processed microstructure due to the lower volume fraction of the ferrite phase. The experimental results reported in this study mainly show that FSP is an easy-to-apply and functional solution to significantly improve the static and cyclic strength of DP600 steel. However, it is clear that the reduced total impact energy absorption capacity after FSP may be taken into account in design strategies.

New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

Municipal solid waste (MSW) is an important destination for abandoned plastics. During the waste disposal process, large plastic debris is broken down into microplastics (MPs) and released into the leachate. However, current research only focuses on landfill leachates, and the occurrence of MPs in other leachates has not been studied. Therefore, herein, the abundance and characteristics of MPs in three types of leachates, namely, landfill leachate, residual waste leachate, and household food waste leachate, were studied, all leachates were collected from the largest waste disposal center in China. The results showed that the average MP abundances in the different types of leachates ranged from (129 ± 54) to (1288 ± 184) MP particles per liter (particles·L−1) and the household food waste leachate exhibited the highest MP abundance (p < 0.05). Polyethylene (PE) and fragments were the dominant polymer type and shape in MPs, respectively. The characteristic polymer types of MPs in individual leachates were different. Furthermore, the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates, leading to a higher percentage (> 80%) of small MPs (20–100 μm) in landfill leachates compared to other leachates. To the best of our knowledge, this is the first study discussing the sources of MPs in different leachates, which is important for MP pollution control during MSW disposal.

Research on incremental forming simulation based on an improved constitutive model

The incremental sheet metal forming process, characterized by the step-by-step deformation of sheet metal using a simple die, is classified as a type of plastic deformation technology. This method allows for the formation of complex-shaped parts even without the use of a specialized die. Its notable characteristic lies in its low forming load and high flexibility. To accurately forecast finite element simulation outcomes for the incremental sheet forming of 2024-O aluminum alloy sheets, constructing a precise constitutive model is essential. Typically, the uniform strain range in traditional unidirectional tensile tests does not surpass 0.3, primarily due to the necking phenomenon. This limitation hampers the accurate prediction of the actual large plastic deformation process. To address this issue, a theoretical model describing the stress-strain relationship in metal plastic deformation processes is developed using crystal plasticity theory. The constitutive model for the forming of 2024-O aluminum alloy is then constructed by adjusting the hardening coefficient and hardening index. Utilizing the improved constitutive model, the incremental sheet forming process is simulated using ABAQUS software. Upon comparison with experimental results, it is observed that the Thickness Average Absolute Relative Errors (TAARE) of the adjusted constitutive model at forming angles of 60°, 55°, and 50° are 0.414%, 0.467%, and 0.256%, and The Thickness Root Mean Square Errors (TRMSE) are determined as 0.0121, 0.0116, and 0.0094, respectively. These results indicate that the constitutive model and parameters established in this study can adequately capture the mechanical behavior of 2024-O aluminum alloy during the incremental sheet forming process.

Real-Time Observation of Nanoscale Kink Band Mediated Plasticity in Ion-Irradiated Graphite: An In Situ TEM Study.

Graphite IG-110 is a synthetic polycrystalline material used as a neutron moderator in reactors. Graphite is inherently brittle and is known to exhibit a further increase in brittleness due to radiation damage at room temperature. To understand the irradiation effects on pre-existing defects and their overall influence on external load, micropillar compression tests were performed using in situ nanoindentation in the Transmission Electron Microscopy (TEM) for both pristine and ion-irradiated samples. While pristine specimens showed brittle and subsequent catastrophic failure, the 2.8 MeV Au2+ ion (fluence of 4.378 × 1014 cm-2) irradiated specimens sustained extensive plasticity at room temperature without failure. In situ TEM characterization showed nucleation of nanoscale kink band structures at numerous sites, where the localized plasticity appeared to close the defects and cracks while allowing large average strain. We propose that compressive mechanical stress due to dimensional change during ion irradiation transforms buckled basal layers in graphite into kink bands. The externally applied load during the micropillar tests proliferates the nucleation and motion of kink bands to accommodate the large plastic strain. The inherent non-uniformity of graphite microstructure promotes such strain localization, making kink bands the predominant mechanism behind unprecedented toughness in an otherwise brittle material.

Resolving Multi-Asperity Contacts at the Nanoscale through Super-Resolution Fluorescence Imaging.

Contact mechanics, spanning nanometer to tectonic scales, faces long-standing challenges arising from multiscale random roughness, which hinders experimental validation of theories. Understanding multi-asperity rough contacts is vital for addressing catastrophic consequences of these contacts failing such as earthquakes and for diverse technological applications. To visualize such contacts, we introduce a super-resolution microscopy method utilizing spontaneous millisecond ON/OFF fluorescence blinking of contact-sensitive molecular rotor molecules immobilized on a glass coverslip. This technique achieves ∼55 nm lateral imaging resolution for rough poly(methyl methacrylate) and glass spheres on glass contacts. For soft polymer spheres due to large plastic deformation, the resolution improvement does not significantly affect the area of real contact. However, for hard glass spheres, the real contact area is found to be 2.4 times smaller than that found by diffraction-limited imaging. This study highlights, through direct visualization, the impact of material stiffness on the nanoscale structure within the area of real contact.

Mechanical behavior and strong oriented design of multi-guide anti-creep energy absorption structure at locomotive end

When trains collide, it is difficult to have a full frontal collision. If the anti creeper fails to play a good guiding function, the train is very likely to climb or derail. In order to study the mechanical behavior of multi-guide anti-creep energy absorption device at locomotive end under eccentric load collision condition. Firstly, the anti-creep principle of the anti-creep device is analyzed, the expression of impedance force/moment of the anti-creep energy absorption device considering the influence of large plastic deformation and dynamic factors is derived. And then, the finite element model of multi-guide anti-creep energy absorption structure of locomotive end is established and verified by experiments. Through the verified finite element model, we simulated and studied the collision performance of the anti-creep energy absorption structure at vertical offset (0 ∼ 100) mm and horizontal offset (0 ∼ 400) mm. The result shows that the vertical migration has little effect on the stability and energy absorption of the anti-creep device. However, horizontal migration has a great influence on it. Based on the situation of horizontal instability, we optimize the strength of the deformation prone area of the anti-creep guide structure according to the bending strength. Compared with the original structure, the improved structure has better anti-creep and energy absorption performance. When the horizontal deviation is 400 mm, the energy absorption of the anti-creep device is increased by 35.50% and the platform force is increased by 16.83% compared with the original structure.