scholarly journals Stiffness and Strength Anisotropy in the Tensile Response of Weft Knitted Fabric-Reinforced Peek- and Pet-Composites

1996 ◽  
Vol 5 (3) ◽  
pp. 096369359600500 ◽  
Author(s):  
J. Karger-Kocsis ◽  
T. Czigány ◽  
J. Gaál ◽  
M. Ostgathe
Keyword(s):  
Mechanical Response ◽  
Tensile Tests ◽  
Thermoplastic Composites ◽  
Knitted Fabric ◽  
Strength Anisotropy ◽  
Strong Anisotropy ◽  
Tensile Response ◽  
Weft Knitted Fabric ◽  
Static Tensile ◽  
Good Agreement

The mechanical response of weft knitted carbon (CF) and glass fibre (GF) fabric-reinforced thermoplastic composites with polyetheretherketone (PEEK) and polyethyleneterephthalate (PET) was studied by dynamic-mechanical thermal analysis (DMTA) and static tensile tests. A strong anisotropy was observed in both stiffness and strength when the specimens were loaded in wale (stronger) and course direction (weaker) of the knit, respectively. The anisotropy factor was estimated by considering the relation of the loop numbers in course and wale direction, that resulted in good agreement with the experimental data.

scholarly journals Deep Drawing of Plain Weft-Knitted Fabric Composites: Part 1.: Cup Height Analysis

1999 ◽  
Vol 8 (6) ◽  
pp. 096369359900800 ◽  
Author(s):  
T.C. Lim ◽  
S. Ramakrishna ◽  
H.M. Shang
Keyword(s):  
Deep Drawing ◽  
Shell Height ◽  
Knitted Fabric ◽  
Fabric Structure ◽  
Weft Knitted Fabric ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Good Agreement

Previous investigations on forming of plain weft-knitted fabric composite sheets show the ease of stretching due to fabric loop straightening. Pure dependence on stretching alone, however, sets the limit to which the shell height can be further increased. Recent deep drawn knitted fabric composites give greater cup height in comparison to stretch formed cup. In this paper a method of predicting the achievable cup height is proposed with due consideration to the fabric structure and tool dimensions. Comparison between the theoretical and experimental cup height shows good agreement.

High Strain Rate Tensile Behavior of Carbon Fiber Reinforced Aluminum Laminates

2005 ◽  
Author(s):  
Yuanxin Zhou ◽  
Pingwen Mao ◽  
Mohammad F. Uddin ◽  
Shaikh Jeelani
Keyword(s):  
Carbon Fiber ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Static Tensile ◽  
Carbon Fiber Reinforced ◽  
Good Agreement

In this paper, loading and loading-unloading tests of carbon fiber reinforced aluminum laminates (CRALL) have been carried out in a tensile impact apparatus, and quasi-static tensile tests have been performed on a MTS-810 machine. Complete stress-strain curves of composite in the strain rate range from 0.001–1200 1/s have been obtained. Experimental results show that CRALL composite is a strain rate sensitivity material, the tensile strength and failure strain both increased with increasing strain rate. A linear strain hardening model has been combined with Weibull distribution function to establish a constitutive equation for CRALL. The simulated stress-strain curves from model are in good agreement with the test data. The analysis of the model shows that the Weibull scale parameter, σ0, increased with increasing strain rate, but Weibull shape parameter, β, can be regarded as a constant.

Bilinear damage evolution in AA2011 wire drawing processes

2022 ◽  
pp. 105678952110725
Author(s):  
Álvaro A González ◽  
Marcela A Cruchaga ◽  
Diego J Celentano
Keyword(s):  
Material Characterization ◽  
Damage Evolution ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Wire Drawing ◽  
Drawing Process ◽  
Effective Plastic Strain ◽  
Predictive Capability ◽  
Two Parameters ◽  
Good Agreement

This paper presents an experimental and numerical analysis of damage evolution in AA2011 aluminum alloy wires drawn under different scenarios. To this end, load-unload tensile tests were firstly carried out in order to characterize the degradation of the mechanical response in every cycle where the experimental results show a bilinear damage relationship in terms of the effective plastic strain. Therefore, a modification of the classical Lemaitre model is proposed in this work in order to reproduce bilinear paths of damage with the addition of only two parameters that can be directly obtained from the material characterization. Then, the damage predictive capability of this new experimental-based model is assessed in numerical simulations of the drawing process in one and two passes (considering for this last case the sequential and tandem configurations) where the computed predictions are compared with the corresponding experimental data showing a good agreement between them.

Bending Properties and Finite Element Modeling of Biaxial Weft Knitted Composites

2012 ◽  
Author(s):  
O. Demircan ◽  
Y. Hamada ◽  
T. Kosui ◽  
A. Nakai ◽  
H. Hamada
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Knitted Fabric ◽  
Bending Properties ◽  
Element Analysis ◽  
Bending Tests ◽  
Bending Property ◽  
Weft Knitted Fabric ◽  
Complex Construction ◽  
Good Agreement

In order to improve the mechanical properties of weft knitted fabric, straight yarns both in weft and warp directions can be integrated. These types of reinforcements are called biaxial weft knitted structures. Finite element analysis is a well known method for analysis of complex construction with complex material properties. Therefore, we wanted to use FEM to express the possibility of prediction of bending properties of complex biaxial weft knitted (BWK) composite structures. The purpose of this study is to investigate bending properties of BWK composites by experimentally and numerically. Two types of six plies composite panels, which include fiber contents, such as glass-glass-aramid and aramid-aramid-aramid, were fabricated by hand lay-up method. After production of composites, bending tests had been conducted on specimens. Glass-glass-aramid composites exhibited superior bending property than aramid-aramid-aramid specimens. The good agreement between the experimental results and numerical results validated the applicability of finite-element method for biaxial weft knitted composites.

Nondestructive Evaluation of Materials Tensile Strength via Nonlinear Acoustics Data

2021 ◽  
Author(s):  
Julian Ehrler ◽  
Alexander Solodov ◽  
Yannick Bernhardt ◽  
Marc Kreutzbruck
Keyword(s):  
Tensile Strength ◽  
Mechanical Response ◽  
Tensile Tests ◽  
Iteration Scheme ◽  
Third Order ◽  
Stress Strain ◽  
The Third ◽  
Static Tensile ◽  
Nonlinear Acoustic ◽  
Quadratic And Cubic Nonlinearities

Abstract The nonlinear acoustic approach is assessed for applications as a nondestructive tool for reconstructing stress-strain curves and quantifying the ultimate tensile strength for variety of materials. The direct algorithm uses the polynomial stress-strain expansion up to the third power of strain and the literature data on the second-order nonlinearity parameters to calculate relevant segments of the stress-strain curves. Since the third-order nonlinearity parameters are unknown for majority of materials the calculations used an iteration scheme to obtain closer approximations to the experimental data available from static tensile tests. The solution to the inverse problem identifies the range of the nonlinearity parameters for a given tensile strength and enables to categorize the contribution of the quadratic and cubic nonlinearities in mechanical response for different materials.

Notched Strength Prediction and Verification of APC-2 Composite Laminates at Elevated Temperature

2009 ◽  
Vol 79-82 ◽  
pp. 1563-1566 ◽  
Author(s):  
Ming Hwa R. Jen ◽  
Yi Chun Sung ◽  
Yu Chung Tseng
Keyword(s):  
Experimental Data ◽  
Elevated Temperature ◽  
Composite Laminates ◽  
Elevated Temperatures ◽  
Characteristic Length ◽  
Tensile Tests ◽  
Stress Criterion ◽  
Static Tensile ◽  
Notched Strength ◽  
Good Agreement

The notched strength of AS-4/PEEK (APC-2) composite laminates with a central hole at elevated temperature was systematically studied by both analytical and empirical methods. First, the APC-2 cross-ply [0/90]4s panels were fabricated and cut into samples. Each sample was drilled a hole in the center with five kinds of diameters, such as d=0(unnotched), 1, 2, 3, and 4mm. Then, the samples were subjected to quasi-static tensile tests at elevated temperatures, including 25°C (RT), 75, 100, 125, 150 and 175°C, to measure their mechanical properties. The average values of received notched strength were affected significantly by stress concentration and high temperature. In analysis the prediction of residual strength by point stress criterion (PSC) was adopted first and found unsatisfactory due to at least 15% errors with experimental data. Then, the modified PSC was used with the varied characteristic length dependent on nature of material and specimen geometry. The predicted notched strengths by the modified PSC model were in very good agreement with experimental data. The predictive results were not only precisely validated, but extended to the application at elevated temperature.

Progressive damage characteristics of screwed single-lap CFRPI-metal joint subjected to tensile loading at RT and 350°C

2021 ◽  
pp. 002199832098559
Author(s):  
Yun-Tao Zhu ◽  
Jun-Jiang Xiong ◽  
Chu-Yang Luo ◽  
Yi-Sen Du
Keyword(s):  
Damage Model ◽  
Tensile Loading ◽  
Tensile Tests ◽  
Displacement Curve ◽  
Progressive Damage ◽  
Damage Characteristics ◽  
Metal Joint ◽  
Static Tensile ◽  
Strength And Stiffness ◽  
Progressive Damage Model

This paper outlines progressive damage characteristics of screwed single-lap CFRPI-metal joints subjected to tensile loading at RT (room temperature) and 350°C. Quasi-static tensile tests were performed on screwed single-lap CCF300/AC721-30CrMnSiA joint at RT and 350°C, and the load versus displacement curve, strength and stiffness of joint were gauged and discussed. With due consideration of thermal-mechanical interaction and complex failure mechanism, a modified progressive damage model (PDM) based on the mixed failure criterion was devised to simulate progressive damage characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint, and simulations correlate well with experiments. By using the PDM, the effects of geometry dimensions on mechanical characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint were analyzed and discussed.

scholarly journals Constitutive Models for the Tensile Behaviour of TRM Materials: Literature Review and Experimental Verification

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 700
Author(s):  
Maria Concetta Oddo ◽  
Giovanni Minafò ◽  
Lidia La Mendola
Keyword(s):  
State Of The Art ◽  
Constitutive Models ◽  
Stress Transfer ◽  
Theoretical Models ◽  
Tensile Tests ◽  
Analytical Models ◽  
Tensile Behaviour ◽  
Tensile Response ◽  
Textile Reinforced Mortar ◽  
Inorganic Matrix

In recent years, the scientific community has focused its interest on innovative inorganic matrix composite materials, namely TRM (Textile Reinforced Mortar). This class of materials satisfies the need of retrofitting existing masonry buildings, by keeping the compatibility with the substrate. Different recent studies were addressed to improve the knowledge on their mechanical behaviour and some theoretical models were proposed for predicting the tensile response of TRM strips. However, this task is complex due to the heterogeneity of the constituent materials and the stress transfer mechanism developed between matrix and fabric through the interface in the cracked stage. This paper presents a state-of-the-art review on the existing constitutive models for the tensile behavior of TRM composites. Literature experimental results of tensile tests on TRM coupons are presented and compared with the most relevant analytical models proposed until now. Finally, a new experimental study is presented and its results are used to further verify the reliability of the literature expressions.

scholarly journals Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3888
Author(s):  
Johanna Maier ◽  
Christian Vogel ◽  
Tobias Lebelt ◽  
Vinzenz Geske ◽  
Thomas Behnisch ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Polyamide 6 ◽  
Thermoplastic Composites ◽  
Efficient Production ◽  
Angle Measurements ◽  
Small Series ◽  
Contact Angle Measurements ◽  
Static Tensile ◽  
Pre Treatment ◽  
Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

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