Honglian Cong

Mechanical properties of co-woven-knitted fabric/epoxy composites incorporating carbon nanotubes

The mechanical properties of co-woven-knitted (CWK)/epoxy resin composites with various carbon nanotubes (CNTs) contents along different directions had been investigated. The tensile failure mode of CWK composites with various CNTs contents also was reported. The results indicate that the stress strain curves are influenced by the CNTs contents obviously, and the failure stress, failure strain and absorbed energy composites with various CNTs contents are linearly increased with the CNTs contents. The tensile failure modes of CWK composites with various CNTs contents tend to be in shear deformation and fiber breakage together, and the failure modes of CWK composites with high CNTs contents mainly are resin shear deformation.

Structural deformation behavior of Jacquardtronic lace based on the mass-spring model

To simulate the structural deformation behavior of Jacquardtronic lace, which is formed on a multibar Jacquard Raschel machine and is widely used in female fashion, the key influencing factors on structural deformation were introduced and a tailored mass-spring model was built in which the lace was considered to be numbers of evenly distributed particles connected by elastane springs. These springs covered structural springs, restriction springs and spiral springs, respectively, created for ground pillars, Jacquard inlays, pattern lapping and elastane yarns. The elastane force on particles was analyzed to study motion state and deformation behavior with the explicit Euler method. The deformation simulated models were implemented by a simulator program via Visual C++ and were tested with a lace sample. Particular attention was paid to analyzing the effect of Jacquard structures and yarn tension on deformation and the detection model was introduced to avoid improper deformation caused by excessive yarn tension. The simulation results showed practicability and efficiency when compared with the real sample.

Experimental investigation on the quasi-static penetration behavior of curved multi-axial warp-knitted composites

The quasi-static penetration tests of the curved glass/phenolic multi-axial warp-knitted (MWK) composites with two types of preform structures and in three different curvatures were implemented. Three phases — elastic deformation phase, progressive damage phase and tension-shear phase were identified to present the different damage behavior stages of curved glass/phenolic MWK composites under quasi-static penetration. Several types of damage modes including matrix cracking, tension-shear of the materials, fiber fracture and interlayer delamination were revealed based on the load-displacement curves and morphology analyses. The results showed that the reinforcement structure and the curvature of the specimens did provide obvious influence onto the quasi-static penetration behaviors of curved glass/phenolic MWK composites and they could be utilized in pointed purposes according to the different mechanical features.

Fabric defect detection algorithm using RDPSO-based optimal Gabor filter

Abstract A new fabric defect detection algorithm is presented in this paper. Instead of a Gabor filter bank, an optimal Elliptical Gabor filter (EGF) is used in the proposed algorithm. For a given non-defective template image, the parameters of the optimal EGF is determined by using the random drift particle swarm optimization (RDPSO) algorithm during the training procedure. During the detecting procedure, a sample image containing the same texture background with the template image is convolved with the optimal EGF. Then, defects discrimination can be carried out to determine whether the sample image contains defects or not. Finally, if the sample image is distinguished to have defects, an adaptive thresholding technique can be applied to locate the defects. Extensive experiments have been carried out to demonstrate the effective detecting performance of the proposed algorithm.

Weft-knitted lace fabric simulation based on the spring-mass model

Purpose The obtained simulation structures could reflect the appearances and the features of the fabrics. The purpose of this paper is to promote a lot for design and manufacturing of weft-knitted lace fabrics (WKLF). Design/methodology/approach The advantages of WKLF compared with warp-knitted ones were displayed. The formation mechanism of the WKLF was analyzed with employing the mechanics principles. Spring-mass model was proposed in this paper to achieve the simulation of the fabrics. End mass points and intermediate mass points were involved in the model. The displacement of end mass points was considered the dominance and the foundation to settle the positions of all the mass points. Findings A novel jacquard lace style fabric with pattern-background effect knitted on circular knitting machine were put forward, which were different from the traditional lace fabrics manufactured on the warp knitting machines. Originality/value First, as the manufacturing equipment, circular knitting machine costs much less than warp knitting machine; second, the elastic performance along weft direction of WKLF is more excellent than that of warp-knitted ones. Third, the excellent extensibility gives nice comfort; furthermore, long floating threads do not exist on the WKLF surface, so that the snag will be avoided.

Relationships between warp-knitted run-in value and process parameters

Abstract The purpose of this study is to investigate the relationship between warp-knitted run-in values and process parameters such as yarn fineness, overlapping, underlapping, take-up density, total threading rate, and machine gauge. Run-in values of 52 samples with different process parameters were measured and analyzed in the method of response surface methodology (RSM) and multilayer perception (MLP). The results of RSM analysis show a significant influence of process parameters on warp-knitted run-in. Moreover, a predictive model is proposed base on the RSM, whose average error rate is confirmed to be 5.29%. In addition, the MLP analysis shows the sequence of influencing importance of process parameters form the high to low is underlapping (51.0%), overlapping (28.5%), take-up density (9.6%), machine gauge (4.7%), yarn fineness (4.0%), and total threading rate (2.2%).