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Post-fire mechanical properties of dual-phase advanced high-strength steel

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-31 DOI: 10.1016/j.tws.2025.113038

Jia-Hui Zhang , Hong-Wei Li , Yixin Zhu , Ying-Min Hao , Hai-Ting Li

Fire-induced high temperatures significantly affect the microstructure and mechanical properties of advanced high-strength steel (AHSS). This study examines the mechanical properties of cold-rolled dual-phase AHSS after exposure to elevated temperatures, identifies the material's degradation trends, and quantitatively analyzes the relationship between grain size, phase transformation, and yield strength. Tensile coupons were extracted from thin-walled sheets and cold-formed C-sections, heated to 300 °C-1000 °C for soaking times of 15 or 60 min, and naturally cooled to room temperature. Tensile tests were conducted to obtain stress-strain curves as well as key mechanical properties after different fire exposure temperatures. Mechanical property degradation trends of high-strength dual-phase steel differ significantly from those of other high-strength steel. In the 600 °C to 1000 °C range, the strength of dual-phase steel drops from 600 °C to 700 °C, then recovers at higher temperatures. The yield strength of the dual-phase AHSS increases by 48.9 % from its lowest value at 700 °C between 800 °C and 900 °C, while the ultimate strength increases by 45.7 % in the same range. Moreover, longer exposure times led to more pronounced deterioration of mechanical properties. This study proposes a post-fire reduction factor prediction formula and a constitutive model for dual-phase AHSS based on different soaking times. Furthermore, microstructure observations of the dual-phase steel after fire exposure were conducted. A modified Hall-Petch equation, considering grain size distribution and phase transformation after fire exposure, accurately predicts post-fire yield strength, aligning well with experimental results.

{"title":"Post-fire mechanical properties of dual-phase advanced high-strength steel","authors":"Jia-Hui Zhang , Hong-Wei Li , Yixin Zhu , Ying-Min Hao , Hai-Ting Li","doi":"10.1016/j.tws.2025.113038","DOIUrl":"10.1016/j.tws.2025.113038","url":null,"abstract":"<div><div>Fire-induced high temperatures significantly affect the microstructure and mechanical properties of advanced high-strength steel (AHSS). This study examines the mechanical properties of cold-rolled dual-phase AHSS after exposure to elevated temperatures, identifies the material's degradation trends, and quantitatively analyzes the relationship between grain size, phase transformation, and yield strength. Tensile coupons were extracted from thin-walled sheets and cold-formed C-sections, heated to 300 °C-1000 °C for soaking times of 15 or 60 min, and naturally cooled to room temperature. Tensile tests were conducted to obtain stress-strain curves as well as key mechanical properties after different fire exposure temperatures. Mechanical property degradation trends of high-strength dual-phase steel differ significantly from those of other high-strength steel. In the 600 °C to 1000 °C range, the strength of dual-phase steel drops from 600 °C to 700 °C, then recovers at higher temperatures. The yield strength of the dual-phase AHSS increases by 48.9 % from its lowest value at 700 °C between 800 °C and 900 °C, while the ultimate strength increases by 45.7 % in the same range. Moreover, longer exposure times led to more pronounced deterioration of mechanical properties. This study proposes a post-fire reduction factor prediction formula and a constitutive model for dual-phase AHSS based on different soaking times. Furthermore, microstructure observations of the dual-phase steel after fire exposure were conducted. A modified Hall-Petch equation, considering grain size distribution and phase transformation after fire exposure, accurately predicts post-fire yield strength, aligning well with experimental results.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"211 ","pages":"Article 113038"},"PeriodicalIF":5.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Preparation and quasi-static compressive behavior of fiber-reinforced truncated conical shells

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-31 DOI: 10.1016/j.tws.2025.113035

Guanghui Deng , Liming Chen , Shaowei Zhu , Zhaoxin Yun , Hangyu Fan , Yong Chen , Xianbo Hou , Tao Liu

Truncated conical shells have numerous applications in aerospace and other engineering fields. However, they have been studied far less extensively than cylindrical shells, and even scarcer research has been done on truncated conical shells made of continuous fiber-reinforced composites. This paper presents a novel fabrication method using unidirectional fiber prepregs to produce conical shell specimens with varying ply angles and stagger angles. Quasi-static compression tests were conducted to obtain fundamental metrics such as load-displacement curves and specific energy absorption. More importantly, a finite element simulation approach, named Partition Approximation Method, was developed. Comparisons with common modeling methods demonstrated that the Partition Approximation Method more effectively predicts the compression response and damage modes. The results indicate that composite conical shell structures exhibit high energy absorption characteristics and relatively smooth stress plateaus due to their progressive failure mechanisms. Designs with stagger angles of 12° and 24° were found to significantly enhance the specimens' compression stability and specific energy absorption performance.

{"title":"Preparation and quasi-static compressive behavior of fiber-reinforced truncated conical shells","authors":"Guanghui Deng , Liming Chen , Shaowei Zhu , Zhaoxin Yun , Hangyu Fan , Yong Chen , Xianbo Hou , Tao Liu","doi":"10.1016/j.tws.2025.113035","DOIUrl":"10.1016/j.tws.2025.113035","url":null,"abstract":"<div><div>Truncated conical shells have numerous applications in aerospace and other engineering fields. However, they have been studied far less extensively than cylindrical shells, and even scarcer research has been done on truncated conical shells made of continuous fiber-reinforced composites. This paper presents a novel fabrication method using unidirectional fiber prepregs to produce conical shell specimens with varying ply angles and stagger angles. Quasi-static compression tests were conducted to obtain fundamental metrics such as load-displacement curves and specific energy absorption. More importantly, a finite element simulation approach, named Partition Approximation Method, was developed. Comparisons with common modeling methods demonstrated that the Partition Approximation Method more effectively predicts the compression response and damage modes. The results indicate that composite conical shell structures exhibit high energy absorption characteristics and relatively smooth stress plateaus due to their progressive failure mechanisms. Designs with stagger angles of 12° and 24° were found to significantly enhance the specimens' compression stability and specific energy absorption performance.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"210 ","pages":"Article 113035"},"PeriodicalIF":5.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143323000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ballistic performance of the UHMWPE fiber-reinforced composite helmet: Experiments and numerical simulations

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-31 DOI: 10.1016/j.tws.2025.113037

Qiran Sun , Jun Lin , Yanzhe Gai , Yongqiang Li

The composite helmet has proven effective in protecting soldiers against high-speed projectile penetration. However, blunt head injuries caused by significant back face deformation (BFD) after ballistic impacts remain a critical issue. The current study evaluated the ballistic performance of an ultra-high-molecular-weight polyethylene (UHMWPE) helmet through ballistic testing and finite element simulation. The 6 mm thick UHMWPE helmet was impacted by a 7.62 × 25 mm full metal jacket (FMJ) bullet at three locations: frontal, lateral, and crown. To capture precise deformation data, simultaneous BFDs were measured using Digital Image Correlation (DIC) technology. Corresponding finite element model was subsequently developed and validated. Both experimental and simulation results indicated that the UHMWPE helmet experienced localized damage with a plastic hinge and notable delamination during impact. Furthermore, a comparative analysis of BFD across different impact locations revealed that the frontal impact presented the highest risk of head injury, followed by the crown and lateral impacts. The study also explored the effect of helmet thickness on ballistic performance, finding that increasing thickness enhanced the helmet's ability to mitigate BFD with a nonlinear weakened trend. The study provides valuable insights into the protective capabilities of UHMWPE helmets and a helpful suggestion for evaluating hybrid composite helmets in future investigations.

{"title":"Ballistic performance of the UHMWPE fiber-reinforced composite helmet: Experiments and numerical simulations","authors":"Qiran Sun , Jun Lin , Yanzhe Gai , Yongqiang Li","doi":"10.1016/j.tws.2025.113037","DOIUrl":"10.1016/j.tws.2025.113037","url":null,"abstract":"<div><div>The composite helmet has proven effective in protecting soldiers against high-speed projectile penetration. However, blunt head injuries caused by significant back face deformation (BFD) after ballistic impacts remain a critical issue. The current study evaluated the ballistic performance of an ultra-high-molecular-weight polyethylene (UHMWPE) helmet through ballistic testing and finite element simulation. The 6 mm thick UHMWPE helmet was impacted by a 7.62 × 25 mm full metal jacket (FMJ) bullet at three locations: frontal, lateral, and crown. To capture precise deformation data, simultaneous BFDs were measured using Digital Image Correlation (DIC) technology. Corresponding finite element model was subsequently developed and validated. Both experimental and simulation results indicated that the UHMWPE helmet experienced localized damage with a plastic hinge and notable delamination during impact. Furthermore, a comparative analysis of BFD across different impact locations revealed that the frontal impact presented the highest risk of head injury, followed by the crown and lateral impacts. The study also explored the effect of helmet thickness on ballistic performance, finding that increasing thickness enhanced the helmet's ability to mitigate BFD with a nonlinear weakened trend. The study provides valuable insights into the protective capabilities of UHMWPE helmets and a helpful suggestion for evaluating hybrid composite helmets in future investigations.</div></div>","PeriodicalId":49435,"journal":{"name":"Thin-Walled Structures","volume":"210 ","pages":"Article 113037"},"PeriodicalIF":5.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A compact vibration isolator based on a structural-functional integrated lattice

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-30 DOI: 10.1016/j.tws.2025.113001

Meng Jia, Ning Dai, Tingwei Wang, Chengqi Zuo

In the aerospace field, vibrations pose significant challenges to the operational accuracy and safety of onboard equipment. In this paper, a compact vibration isolator based on a structural-functional integrated lattice is proposed. A parametric model for the isolator is developed to tune the first-order natural frequency of the vibration system. Firstly, an optimization objective of maximizing compliance (minimizing stiffness) is introduced based on the linear system’s response characteristics. Zigzag structures are designed using topology optimization, and a calculation method for the structural stiffness is proposed to reduce iteration cycles. Secondly, half of the body-centered cubic (H-BCC) lattice is employed to reduce the mass and stiffness of the zigzag structures. The stiffness of the H-BCC isolator is equivalently calculated, and the calculation method is validated through quasi-static experiments. Thirdly, a piecewise linear model is developed to analyze the stiffness nonlinearity caused by structural densification. The stability and bifurcation of the harmonic response are studied using the Floquet multipliers and the system response is calculated numerically. The nonlinear system’s superharmonic resonance is manifested through the short-time Fourier transform. Finally, vibration experiments are conducted to evaluate the performance. The harmonic response demonstrates that the designed isolator effectively tunes the system’s natural frequency, thereby broadening the vibration attenuation bandwidth. The response discontinuity caused by stiffness nonlinearity is validated through both calculations and experiments. Under random vibration excitation, the proposed isolator exhibits a vibration isolation efficiency exceeding 90%, confirming the effectiveness under both linear and nonlinear conditions.

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引用次数: 0

Experimental study on the mechanical and thermal properties of PEEK, CF/PEEK, and GF/PEEK thin-walled cylinders under static compressive tests

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-30 DOI: 10.1016/j.tws.2025.113032

Shuyan Nie , Kunyong Guo , Yuanhao Tian , Liming Chen , Zhaoxin Yun , Xin Pan , Weiguo Li , Jie Wang , Xianbo Hou , Shaowei Zhu , Tao Liu , Zhenhua Song

Polyether ether ketone (PEEK) and its fiber reinforced composite thin-walled tube structures (TWCs) are widely used in engineering, but their mechanical properties under thermal conditions are rarely reported. In this paper, the static compressive mechanical properties of PEEK-TWCS, short glass fiber reinforced PEEK TWCS (GF/PEEK-TWCS) and short carbon fiber reinforced PEEK TWCS (CF/PEEK-TWCS) at 20 ℃ and 170 ℃ were investigated experimentally. The outcomes underscore that the compressive strength, specific energy absorption and stiffness of the cylinders are significant sensitive to temperature, with PEEK-TWCS demonstrating the highest sensitivity, exhibiting a reduction of over 75 % at 170 °C. Comparatively, the reinforcing effects of carbon fibers and glass fibers are markedly pronounced at 170 °C, substantially ameliorating the mechanical performance of the cylindrical structures. Utilizing a 3D-Digital Image Correlation (DIC) optical strain measurement system, an inhomogeneous strain distribution in the elastic phase was observed for all materials, with increasing compression, a buckling half-wave formed, leading to localized buckling. According to the micro-nano electron computed tomography scanner (Nano-CT), the plasticity of GF/PEEK-TWCS is better than that of CF/PEEK-TWCS and PEEK-TWCS at 20 °C. In addition, microscopic fracture surface analysis revealed that the ductile matrix behavior in CF/PEEK, juxtaposed with brittle fiber fracture, indicative of interface damage and fiber pull-out. In contrast, PEEK displayed brittle fracture characteristics. This research provides support for the temperature-dependent mechanical behavior of PEEK-based composites, offering a foundation for the development of advanced materials for high-temperature applications.

聚醚醚酮（PEEK）及其纤维增强复合材料薄壁管结构（TWCs）被广泛应用于工程领域，但其在热条件下的力学性能却鲜有报道。本文通过实验研究了 PEEK-TWCS、短玻璃纤维增强 PEEK TWCS（GF/PEEK-TWCS）和短碳纤维增强 PEEK TWCS（CF/PEEK-TWCS）在 20 ℃ 和 170 ℃ 下的静态压缩力学性能。结果表明，圆柱体的抗压强度、比能量吸收和刚度对温度非常敏感，其中 PEEK-TWCS 的敏感性最高，在 170 ℃ 时降低了 75% 以上。相比之下，碳纤维和玻璃纤维在 170 °C 时的增强效果明显，大大改善了圆柱形结构的机械性能。利用三维数字图像相关（DIC）光学应变测量系统，观察到所有材料在弹性阶段的应变分布不均匀，随着压缩量的增加，形成了屈曲半波，导致局部屈曲。根据微纳电子计算层析成像扫描仪（Nano-CT）的结果，在 20 °C 时，GF/PEEK-TWCS 的塑性优于 CF/PEEK-TWCS 和 PEEK-TWCS。此外，显微断裂面分析表明，CF/PEEK 的韧性基体行为与脆性纤维断裂并存，表明存在界面损伤和纤维拉出。相比之下，PEEK 显示出脆性断裂特征。这项研究为基于 PEEK 的复合材料随温度变化的机械行为提供了支持，为开发高温应用的先进材料奠定了基础。

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引用次数: 0

Nonlinear static and dynamic responses of edge-cracked FG-GPLRC dielectric beams with internal pores 带有内孔的边缘开裂 FG-GPLRC 介电梁的非线性静态和动态响应

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-28 DOI: 10.1016/j.tws.2025.113016

Zhi Ni, Shaoyu Zhao, Jie Yang

The dielectric properties of functionally graded (FG) graphene platelets (GPLs) reinforced composite (FG-GPLRC) beams enable tunable mechanical responses under external electric fields and hence offer an effective way for enhanced control of structural performance. This paper investigates nonlinear static and dynamic responses of FG-GPLRC dielectric beams with internal pores and an open edge crack. A two-step hybrid mechanical model is developed to determine the material properties of the multiphase composites. The governing equations, incorporating damping and dielectric properties, are derived within the framework of Timoshenko beam theory and the nonlinear von Kármán strain-displacement relationship. The stress intensity factor (SIF) at the crack tip of the cracked FG-GPLRC beam is obtained via finite element method (FEM). Differential quadrature (DQ) and incremental harmonic balance (IHB) methods combined with the arc-length algorithm methods are utilized to solve the nonlinear system. After the present analysis has been verified, a comprehensive parametric study is conducted to examine the effects of internal pore attributes, crack location and depth, damping, GPL properties and the applied electric field on the nonlinear bending, free and forced vibrations of the cracked FG-GPLRC beam. The study indicates that the internal pore attributes and crack location and depth have a significant impact on the nonlinear frequency, dimensionless amplitude, and peak amplitude excitation frequency of the cracked FG-GPLRC beam under an applied voltage.

功能分级（FG）石墨烯平板（GPLs）增强复合材料（FG-GPLRC）梁的介电特性可对外部电场产生可调的机械响应，因此为增强结构性能控制提供了有效途径。本文研究了具有内部孔隙和开放边缘裂缝的 FG-GPLRC 介电梁的非线性静态和动态响应。本文建立了一个两步混合力学模型，以确定多相复合材料的材料特性。在 Timoshenko 梁理论和非线性 von Kármán 应变-位移关系的框架内，导出了包含阻尼和介电特性的控制方程。开裂的 FG-GPLRC 梁裂缝顶端的应力强度因子（SIF）是通过有限元法（FEM）获得的。微分正交（DQ）和增量谐波平衡（IHB）方法与弧长算法方法相结合，用于求解非线性系统。本分析经过验证后，进行了全面的参数研究，以检验内部孔隙属性、裂缝位置和深度、阻尼、GPL 属性和外加电场对开裂 FG-GPLRC 梁的非线性弯曲、自由和强迫振动的影响。研究表明，内部孔隙属性、裂纹位置和深度对外加电压下开裂 FG-GPLRC 梁的非线性频率、无量纲振幅和峰值振幅激励频率有显著影响。

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引用次数: 0

Compressive behavior of a novel cold-formed steel built-up box section: Tests, modelling and design

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-28 DOI: 10.1016/j.tws.2025.113024

Wei Wang , Krishanu Roy , Hooman Rezaeian , Kang Huang , Shubham Tiwari , James B.P. Lim

This paper investigates a novel built-up box section constructed from single cold-formed steel (CFS) C- and U-sections, which are connected using self-drilling screws along their extended flanges. Both experimental and numerical analyses were conducted to study the buckling behavior and ultimate strength of these pin-ended, axially loaded CFS built-up box section columns. The study focuses on key parameters such as thicknesses (0.95 mm and 1.15 mm), screw spacing (300 mm and 600 mm), and slenderness ratios (42, 72, 102, 132). A total of 48 specimens were tested under axial compression, exhibiting significant local-distortional and local-flexural interactive buckling modes. Finite element models were developed using ABAQUS software and validated based on the experimental results. The numerical simulations were used to assess the effects of screw spacing and thickness on the ultimate strength of the built-up box columns. The ultimate strengths obtained from both the experiments and the finite element analysis were then compared to the predictions made using the Effective Width Method (EWM) and the Direct Strength Method (DSM), as outlined in AISI S100 (2016) and AS/NZS 4600 (2018). The comparison shows that DSM overestimated the axial capacity of these novel built-up box section columns by an average of 15 %, while EWM was overly conservative, with mean experimental-to-design strength ratios exceeding 2.5.

本文研究了一种由单个冷弯型钢（CFS）C 型截面和 U 型截面构成的新型内置箱形截面，这些截面使用自钻螺钉沿其扩展翼缘进行连接。通过实验和数值分析，研究了这些销端轴向加载 CFS 构建箱形截面柱的屈曲行为和极限强度。研究的重点是厚度（0.95 毫米和 1.15 毫米）、螺钉间距（300 毫米和 600 毫米）和细长比（42、72、102、132）等关键参数。共对 48 个试样进行了轴向压缩测试，结果显示出显著的局部扭曲和局部挠性交互屈曲模式。使用 ABAQUS 软件开发了有限元模型，并根据实验结果进行了验证。数值模拟用于评估螺杆间距和厚度对加固箱形柱极限强度的影响。实验和有限元分析得出的极限强度与 AISI S100 (2016) 和 AS/NZS 4600 (2018) 中概述的有效宽度法 (EWM) 和直接强度法 (DSM) 的预测值进行了比较。比较结果表明，DSM 高估了这些新型内置箱形截面柱的轴向承载力，平均高估了 15%，而 EWM 则过于保守，实验强度与设计强度的平均比值超过了 2.5。

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引用次数: 0

Implosion collapse of externally pressurized steel/CFRP/titanium cylindrical shells with a hybrid sandwich thin-walled structure 具有混合夹层薄壁结构的外部加压钢/CFRP/钛圆柱形壳体的内爆坍塌

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-28 DOI: 10.1016/j.tws.2025.112988

Xinlong Zuo , Jinwei Yu , Wenxian Tang , Yongsheng Li

A steel/CFRP/titanium cylindrical shell with a hybrid sandwich structure was proposed, designed, fabricated and hydrostatically experimented. Subsequently, to evaluate the collapse load of such hybrid sandwich structure under external pressure without excessive computational cost, an analytical formula was derived in this study. The rationality of the derived formula was verified by the comparison with experimental and numerical investigations. The hybrid sandwich structure comprised an inner steel metallic layer, a CFRP core layer, and an outer titanium foil metallic skin layer. To determine the contribution of the sandwich structure to the loading capacity, this study compared the loading capacity of the hybrid sandwich shells with that of single-layer steel cylindrical shells. Three nominally identical multilayer cylindrical shells with a sandwich structure and three nominally identical single-layer cylindrical shells were fabricated. The dimensions of these shells were measured, and the shells were subjected to hydrostatic testing. Moreover, theoretical and numerical analyses were performed to evaluate the collapse properties of the fabricated shells. The experimental, theoretical, and numerical data of this study agreed with each other and suggested that the loading capacity of the multilayer shell samples was considerably higher than that of the single-layer shell samples. Additionally, the structural efficiency of the hybrid sandwich shell samples was approximately 141.9 % higher than that of the single-layer samples.

本研究提出了一种钢/CFRP/钛混合夹层结构的圆柱形壳体，并对其进行了设计、制造和水压试验。随后，为了在不花费过多计算成本的情况下评估这种混合夹层结构在外压作用下的坍塌载荷，本研究推导出了一个解析公式。通过与实验和数值研究的对比，验证了推导公式的合理性。混合夹层结构由内层钢金属层、CFRP 核心层和外层钛箔金属表皮层组成。为了确定夹层结构对承载能力的贡献，本研究将混合夹层壳体的承载能力与单层钢圆柱形壳体的承载能力进行了比较。研究人员制作了三个名义上相同的夹层结构多层圆柱形壳体和三个名义上相同的单层圆柱形壳体。对这些外壳的尺寸进行了测量，并对外壳进行了流体静力学测试。此外，还进行了理论和数值分析，以评估制作的壳体的坍塌特性。本研究的实验、理论和数值数据相互吻合，表明多层壳体样品的承载能力大大高于单层壳体样品。此外，混合夹层壳样本的结构效率比单层样本高出约 141.9%。

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引用次数: 0

Influence of prebuckling deflections on the elastic lateral-torsional buckling of thin-walled beams with various end supports: Analytical and numerical investigations in the case of doubly-symmetric cross-sections 预屈曲挠度对带有各种端部支撑的薄壁梁的弹性侧向扭转屈曲的影响：双对称截面情况下的分析和数值研究

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-28 DOI: 10.1016/j.tws.2025.113025

Ghaith A. Abu Reden, Sandor Adany (Professor)

In this paper analytical and numerical studies are presented to investigate the effect of prebuckling deflections on the elastic lateral-torsional buckling of single-span beams with doubly symmetric cross-sections. A special emphasis is placed on various support conditions. New analytical formulae are derived for classic end supports, then numerical studies are performed comparing the critical moments from analytical formulae and beam finite element solutions. Since in standard finite element linear buckling analyses the effect of prebuckling deflections is not accounted for, a specialized iterative buckling analysis is employed. The results prove that the critical moment can efficiently be calculated by classic numerical methods, even if the effect of prebuckling deflection is considered. The existing literature suggests that the prebuckling effect is positive, with the critical moment increase being influenced primarily by the ratio of minor-to-major moment of inertia, however, in this paper it is shown that this can be confirmed only in the case of simply supported beams with small torsional rigidity. Both the analytical formulae and the numerical results clearly show that the torsional rigidity of the cross-section and the length of the beam modify the prebuckling effect, while, unlike suggested by the literature, the effect of prebuckling deflections is strongly influenced by the end supports, with some supports leading to negative prebuckling effect.

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引用次数: 0

A physics-informed neural network framework for laminated composite plates under bending 弯曲下层压复合板的物理信息神经网络框架

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2025-01-27 DOI: 10.1016/j.tws.2025.113014

Weixi Wang, Huu-Tai Thai

The use of machine learning in the field of structural engineering is becoming more common. However, the high dependence of traditional purely data-driven models on the size and quality of the database has posed challenges to the practical application of machine learning. Applying physics-informed machine learning can achieve accurate predictions while reducing the need for extensive input data. This study develops a Physics-Informed Neural Network (PINN) framework to predict the bending behaviors of laminated composite plates. In this framework, the Classical Laminated Plates Theory (CLPT) is incorporated as the physical constraint, and the loss function is formulated based on the energy method. The machine learning prediction results were validated with the CLPT analytical solutions and Finite Element Method (FEM) results, which were sourced from existing literature. These validations demonstrate that the PINN framework achieves satisfactory bending behavior predictions, potentially serving as a promising alternative.

引用次数: 0