Knittability of Basalt Fiber Weft-Knitted Fabrics for Composite Reinforcement Based on Properties of Advanced Composite Materials

2012 ◽  
Vol 583 ◽  
pp. 207-210 ◽  
Author(s):  
Qiu Mei Wang ◽  
Xiao Yang ◽  
Jing Gao ◽  
Peng Fei Song
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Basalt Fiber ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Fiber Damage ◽  
Advanced Composite ◽  
Damage Degree ◽  
Advanced Composite Materials ◽  
Fiber Fineness

The knittability of basalt fiber yarn for knitted fabrics was estimated from two aspects. Firstly the effect of 3 kinds of head size of needle hook on the loop strength of basalt fiber yarn was analysis by the experimental data. Then the basalt fiber yarn was knitted into plain, 1*1 rib and all needle rib knitted fabrics in 5 different loop lengths in a flat knitting machine. The influence of loop length, fabric stitch and fiber fineness on the fiber damage degree were studied by means of the tensile strength of the yarn taken from the fabrics for all kinds of fabrics. The experimental results show that for these 3 kinds of basalt weft knitted fabrics there is a best loop length in which the fiber damage degree caused by the knitting process is the smallest and the value is different for each stitch.

Process development and compression behavior of innovative 3D bi-directional flat-knitted spacer-reinforced composites

2021 ◽  
pp. 152808372199277
Author(s):  
Mohammad Pourheidar Shirazi ◽  
Hossein Hasani
Keyword(s):  
Process Development ◽  
Lower Surface ◽  
Impact Behavior ◽  
Reinforced Composites ◽  
Surface Layers ◽  
Knitted Fabrics ◽  
Compression Behavior ◽  
Advanced Composite ◽  
Advanced Composite Materials ◽  
Spacer Fabrics

3D knitted fabrics are regarded as a viable option for advanced composite materials. Flat-knitted spacer fabrics (FKSF) which are in the category of 3D knitted structures have attracted many attentions due to outstanding characterizations such as high formability and good impact behavior. These structures consist of two surface layers which are linked together by multiple knitted connecting layers. Despite the merits of 3D-FKSFs as composite reinforcements, they have some structural restrictions such as limited thickness. This study aims to develop and characterize bi-directional 3D knitted spacer structures which could be replaced with conventional FKSFs. In the developed structures, the upper and lower surface layers are connected together by two truncated pyramids which can be configurated in any dimensions using an innovative knitting technique. For providing a report regarding their compression behavior, these 3D structures were produced in two different thicknesses on an electronic flat knitting machine. Then, they were impregnated with epoxy resin via vacuum resin transfer molding and the cured composites were subjected to compression force. The results revealed that their compression behavior is similar to the behavior of conventional honey-comb sandwich structures.

Geometry of compact plain knitted structures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gamini Lanarolle
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Present Model ◽  
Major Axis ◽  
Minor Axis ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Content Type ◽  
Mathematical Relationships ◽  
The Mathematical Model

Purpose The purpose of this paper is to develop mathematical relationships to calculate the loop length to knit compact plain knitted fabrics and to validate the model using the fabric parameters of commercial fabrics. Design/methodology/approach Ellipse defines the shape of the head of a knitted loop and straight lines define the arms of a knitted loop. The mathematical relationships developed relate the yarn count to the loop length of compact knitted fabrics. The experimental data and the data from previous similar research validate the accuracy of the mathematical model. Findings The model can calculate loop lengths to knit compact plain knitted fabrics in terms of thickness of the yarn and the coefficient defined to express the ratio of minor axis to major axis of the ellipse that defines the shape of the head of the loop. The mathematical model can deliver several loop lengths to produce compact plain knitted fabrics for different values of this coefficient. For commercial fabrics the error of the model was 0.53%. Originality/value The present model defines the head of the loop as an ellipse. The uniqueness of the present model is that several ellipses can exist for any given yarn thickness for a range of values assigned to the minor axis of the ellipse. The accuracy of the model against experimental data ascertains that the model is closer to the reality for commercial fabrics and proves the uniqueness of the model. Further, this model is an ideal and a simple model to introduce knitted loop configurations in teaching knitted fabric geometry.

scholarly journals Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2171
Author(s):  
Armin Yousefi ◽  
Ahmad Serjouei ◽  
Reza Hedayati ◽  
Mahdi Bodaghi
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Element Model ◽  
Plastic Strain Amplitude ◽  
Friction Stir ◽  
Probe Hole ◽  
Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

Quantitative Analysis of Pre-Strain Effect on Mechanical Properties of the Austenitic Stainless Steel

2014 ◽  
Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Yield Strength ◽  
Tensile Testing ◽  
Control Mode ◽  
Strain Effect ◽  
Strain Control

The test of austenitic stainless steel specimens with strain control mode of pre-strain was carried out. The range of pre-strain is 4%, 5%, 6%, 7%, 8%, 9% and 10% on austenitic stainless steel specimens, then tensile testing of these samples was done and their mechanical properties after pre-strain were gotten. The results show that the pre-strain has little effect on tensile strength, and enhances the yield strength more obviously. According to the experimental data, we get a relational expression of S30408 between the value of yield strength and pre-strain. We can obtain several expressions about different kinds of austenitic stainless steel by this way. It is convenient for designers to get the yield strength of austenitic stainless steel after pre-strain by the value of pre-strain and the above expression.

Sign in / Sign up

Export Citation Format

Share Document