Jian Xiong^1,*, Pengcheng Xue¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.4, pp. 1-3, 2024, DOI:10.32604/icces.2024.011785

Abstract Carbon fiber-reinforced plastic (CFRP) composite sandwich structures, due to their excellent mechanical properties and lightweight characteristics, are widely used in aerospace, marine, automotive, and wind turbine blade structures [1]. Different from traditional sandwich structures, composite honeycomb sandwich structures exhibit brittle properties, potentially leading to sudden and catastrophic debonding failure without any warning. Consequently, the interfaces between the face-core and the inner core may become the weakest parts of the structural system.
This paper presents a theoretical and experimental investigation into the debonding behavior of the face-core and inner core in composite honeycomb sandwich structures. Based on… More >

Jaewook Lee¹, Byung-Dae Park^1,*, Qinglin Wu²

Journal of Renewable Materials, Vol.12, No.7, pp. 1187-1205, 2024, DOI:10.32604/jrm.2024.049948 - 21 August 2024

Abstract Lignin is the most abundant aromatic natural polymer, and receiving great attention in replacing various petroleum-based polymers. The aim of this study is to investigate the feasibility of technical lignin as a polyol for the synthesis of non-isocyanate polyurethane (NIPU) adhesives to substitute current polyurethane (PU) adhesives that have been synthesized with toxic isocyanate and polyols. Crude hardwood kraft lignin (C-HKL) was extracted from black liquor from a pulp mill followed by acetone fractionation to obtain acetone soluble-HKL (AS-HKL). Then, C-HKL, AS-HKL, and softwood sodium lignosulfonate (LS) were used for the synthesis of technical lignin-based… More > Graphic Abstract

Shuai Chen¹, Yinwei Ma², Zhongshu Wang², Zongmei Xu³, Song Zhang¹, Jianle Li¹, Hao Xu¹, Zhanjun Wu^1,*

Structural Durability & Health Monitoring, Vol.18, No.2, pp. 125-141, 2024, DOI:10.32604/sdhm.2024.042594 - 22 March 2024

Abstract The safety and integrity requirements of aerospace composite structures necessitate real-time health monitoring throughout their service life. To this end, distributed optical fiber sensors utilizing back Rayleigh scattering have been extensively deployed in structural health monitoring due to their advantages, such as lightweight and ease of embedding. However, identifying the precise location of damage from the optical fiber signals remains a critical challenge. In this paper, a novel approach which namely Modified Sliding Window Principal Component Analysis (MSWPCA) was proposed to facilitate automatic damage identification and localization via distributed optical fiber sensors. The proposed method More > Graphic Abstract

Ismail Shah^1,2, Jing Li^1,3,4,*, Nauman Khan⁵, Hamad R. Almujibah⁶, Muhammad Mudassar Rehman², Ali Raza⁷, Yun Peng^3,4

Journal of Renewable Materials, Vol.12, No.1, pp. 167-186, 2024, DOI:10.32604/jrm.2023.031503 - 23 January 2024

Abstract Recycled steel fiber reinforced concrete is an innovative construction material that offers exceptional mechanical properties and durability. It is considered a sustainable material due to its low carbon footprint and environmental friendly characteristics. This study examines the key influencing factors that affect the behavior of this material, such as the steel fiber volume ratio, recycled aggregate replacement rate, concrete strength grade, anchorage length, and stirrup constraint. The study investigates the bond failure morphology, bond-slip, and bond strength constitutive relationship of steel fiber recycled concrete. The results show that the addition of steel fibers at 0.5%,… More >

DIBYENDU S. BAG^*, SHILPI TIWARI, AKANSHA DIXIT, KM. MEENU

Journal of Polymer Materials, Vol.40, No.1-2, pp. 105-123, 2023, DOI:10.32381/JPM.2023.40.1-2.9

Abstract In this paper, we report the microstructural investigation and influence of H-bonding on the thermal behavior e.g., glass transition (T_g ) and thermal degradation of chiral copolymers of (R)- N-(1-phenyl-ethyl) methacrylamide (R-NPEMAM) and 2-hydroxy ethyl methacrylate (HEMA). The T_g increases with the increase of chiral unit content in the copolymers and then attains optimum at around 25 mole % of chiral content. Thereafter it decreases with the increase of chiral content. The effect of copolymer composition and secondary interaction associated with the Hbonding on the thermal properties of these copolymers was also studied. Secondary interaction, specifically More >

Mingjing Li^1,*, Leiting Dong¹, Satya N. Atluri²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.09689

Abstract The Fragile Points Method (FPM) is a discontinuous meshless method based on the Galerkin weak form [1]. In the FPM, the problem domain is discretized by spatial points and subdomains, and the displacement trial function of each subdomain is derived based on the points within the support domain. For this reason, the FPM doesn’t suffer from the mesh distortion and is suitable to model complex structural deformations. Furthermore, similar to the discontinuous Galerkin finite element method, the displacement trial functions used in the FPM is piece-wise continuous, and the numerical flux is introduced across each… More >

Guobing Xiong¹, Lu Hong², Zehui Ju³, Xiaoning Lu^3,*, Juwan Jin^3,*

Journal of Renewable Materials, Vol.11, No.9, pp. 3447-3461, 2023, DOI:10.32604/jrm.2023.027430 - 20 July 2023

Abstract The study characterized the curing behaviors of phenol formaldehyde (PF) resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric conditions. The changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as well. It was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made device. FTIR spectra indicated the degree of polycondensation of hydroxymethyl gradually increased with the increase in temperature. It was also observed that a… More >

Haowen Wu¹, Zhanli Yi¹, Tianyou Guo^2,*

International Journal of Mental Health Promotion, Vol.25, No.3, pp. 375-387, 2023, DOI:10.32604/ijmhp.2022.021505 - 21 February 2023

Abstract Background: Adolescents are highly vulnerable to depressive symptoms worldwide partially because of limited social supports. However, it still remains largely unknown regarding the associations between social support(s) and depressive symptoms among adolescents living in low- and middle-income countries (LMICs). The aim of this study aimed to explore the associations between different types of social support and depressive symptoms in adolescents from LMICs. Methods: Data were retrieved from the Global School-based Health Survey (GSHS) in which 92,551 adolescents (50.6% females) were included with mean of 15.6 years. Depressive symptoms in the past one month as the dependent… More >

Jure Žigon^1,*, Vit Šeda², Petr Čermák², Milan Šernek¹

Journal of Renewable Materials, Vol.11, No.2, pp. 991-1001, 2023, DOI:10.32604/jrm.2022.023584 - 22 September 2022

Abstract Various crosslinking agents can be added to the formulations of natural-based adhesives for wood bonding in order to achieve better durability and higher strength of the formed joints. In the present study, the effect of hexamethylenediamine (HMDA) addition on the performance of liquefied wood (LW) adhesive for wood bonding is investigated. Differential scanning calorimetry showed the improved thermal stability and crosslinking of the LW adhesive with HMDA. The intensified presence of amide linkages (C–N bonds) was found in LW+HMDA with attenuated total reflection Fourier transform infrared spectroscopy. Analysis of the bonded joints using an automated… More >

Shiqin He^*, Jiaxing Zhao, Chunyue Wang, Hui Wang

Structural Durability & Health Monitoring, Vol.16, No.3, pp. 195-212, 2022, DOI:10.32604/sdhm.2022.08886 - 18 July 2022

Abstract In marine environments, the durability of reinforced concrete structures such as bridges, which suffer from the coupled effects of corrosion and fatigue damage, is significantly reduced. Fatigue loading can result in severe deterioration of the bonds between reinforcing steel bars and the surrounding concrete, particularly when reinforcing bars are corroded. Uniaxial tension testing was conducted under static loading and fatigue loading conditions to investigate the bonding characteristics between corroded reinforcing bars and concrete. An electrolyte corrosion technique was used to accelerate steel corrosion. The results show that the bond strength was reduced under fatigue loading, More >