scholarly journals Dimensional Variations of General Curved Composite Parts

2008 ◽  
Vol 41-42 ◽  
pp. 377-383
Author(s):  
Chen Song Dong
Keyword(s):  
Composite Materials ◽  
Process Development ◽  
Closed Form Solution ◽  
Weight Ratio ◽  
Tolerance Analysis ◽  
High Strength ◽  
Form Solution ◽  
Design Stage ◽  
Early Design Stage ◽  
Manufacturing Assembly

With the increasing demands of energy efficiency and environment protection, composite materials have become an important alternative for traditional materials. Composite materials offer many advantages over traditional materials including: low density, high strength, high stiffness to weight ratio, excellent durability, and design flexibility. Despite all these advantages, composite materials have not been as widely used as expected because of the complexity and cost of the manufacturing process. One of the main causes is associated with poor dimensional control. General curved composite parts are often used as the structural components in the composite industry. Due to the anisotropic material nature, process-induced dimensional variations make it difficult for tighttolerance control and limit the use of composites. This research aims to develop a practical approach for the design of general curved composite parts and assembly. First, the closed-form solution for the process-induced dimensional variations, which is commonly called spring-in, was derived. For a general curved composite part, a Structural Tree Method (STM) was developed to divide the curve into a number of pieces and calculate the dimensional variations sequentially. This method can be also applied to an assembly of composite parts. The approach was validated through a case study. The method presented in this paper provides a convenient and practical tool for the dimensional and tolerance analysis in the early design stage of general curved composite parts and assembly, which is extremely useful for the realization of affordable tight tolerance composites. It also provides the foundation of Integrated Product/Process Development (IPPD) and Design for Manufacturing/Assembly (DFM/DFA) for composites.

Fuzzy Sensitivity Analysis in the Context of Dimensional Management

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Thomas Oberleiter ◽  
Björn Heling ◽  
Benjamin Schleich ◽  
Kai Willner ◽  
Sandro Wartzack
Keyword(s):  
Tolerance Analysis ◽  
Design Stage ◽  
Special Focus ◽  
Total System ◽  
Early Design Stage ◽  
Technical Requirements ◽  
Geometric Deviations ◽  
Weak Points ◽  
Dimensional Management ◽  
The Impact

Real components always deviate from their ideal dimensions. This makes every component, even a serial production, unique. Although they look the same, differences can always be observed due to different scattering factors and variations in the manufacturing process. All these factors inevitably lead to parts that deviate from their ideal shape and, therefore, have different properties than the ideal component. Changing properties can lead to major problems or even failure during operation. It is necessary to specify the permitted deviations to ensure that every single product nevertheless meets its technical requirements. Furthermore, it is necessary to estimate the consequences of the permitted deviations, which is done via tolerance analysis. During this process, components are assembled virtually and varied with the uncertainties specified by the tolerances. A variation simulation is one opportunity to calculate these effects for geometric deviations. Since tolerance analysis enables engineers to identify weak points in an early design stage, it is important to know the contribution that every single tolerance has on a certain quality-relevant characteristic, to restrict or increase the correct tolerances. In this paper, a fuzzy-based method to calculate the sensitivity is introduced and compared with the commonly used extended Fourier amplitude sensitivity test (EFAST) method. Special focus of this work is the differentiation of the sensitivity for the total system and the sensitivities for the subsystems defined by the α-cuts of the fuzzy numbers. It discusses the impact of the number of evaluations and nonlinearity on sensitivity for EFAST and the fuzzy-based method.

Comparison of Different Sensitivity Analysis Methods in the Context of Dimensional Management

2017 ◽  
Author(s):  
Björn Heling ◽  
Thomas Oberleiter ◽  
Benjamin Schleich ◽  
Kai Willner ◽  
Sandro Wartzack
Keyword(s):  
Tolerance Analysis ◽  
Sensitivity Analyses ◽  
Design Stage ◽  
Fuzzy Arithmetic ◽  
Early Design Stage ◽  
Technical Requirements ◽  
Strongly Connected ◽  
Geometric Deviations ◽  
Comparison Of The Results ◽  
Dimensional Management

Although mass production parts look the same, every manufactured part is unique, at least on a closer inspection. The reason for this is that every manufactured part is inevitable subjected to different scattering influencing factors and variation in the manufacturing process, such as varying temperatures or tool wear. All these factors inevitably lead to parts, which deviate from their ideal shape. Products, which are built from these deviation-afflicted parts consequently show deviations from their ideal properties. To ensure that every single product nevertheless meets its technical requirements, it is necessary to specify the permitted deviations. Furthermore it is necessary to estimate the consequences of the permitted deviations, which is done via tolerance analysis. During this process the imperfect parts are assembled virtually and the effects of the geometric deviations can be calculated during a variation simulation. Since the tolerance analysis is to enable engineers to identify weak points in an early design stage it is important to know which contribution every single tolerance has on a certain quality-relevant characteristic, to restrict or increase the correct tolerances. In this paper two different approaches are shown and compared to represent the statistical behavior and the strongly connected sensitivity analyses. In particular a newly developed approach, which is based on fuzzy arithmetic, is compared to the established EFAST-method. The exemplary application of both methods and the comparison of the results are illustrated on a case study.

Impact of the Harsh Environment on E-Glass Epoxy Composite

2019 ◽  
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid Ismail Mourad ◽  
Beckry Abdel-Magid ◽  
Mohammad Mozumder ◽  
Yaser Afifi
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
Oil And Gas ◽  
Epoxy Composite ◽  
Uv Light ◽  
Weight Ratio ◽  
High Strength ◽  
Industrial Applications ◽  
Harsh Environment ◽  
Sustained Loads

Abstract Composite materials are being used in many industrial applications such as automobile, aerospace, marine, oil and gas industries due to their high strength to weight ratio. The long-term effect of sustained loads and environmental factors that include exposure to UV light, temperature, and moisture have been under investigation by many researchers. The major objective of this study is to evaluate the effects of harsh environment (e.g. seawater and high temperature) on the structural properties of E-glass epoxy composite materials. These effects were studied in terms of seawater absorption, permeation of salt and contaminants, chemical and physical bonds at the interface and degradation in mechanical properties. Samples were immersed in seawater at room temperature (23°C), 65°C and 90°C for the duration of 6 months. Results show that seawater absorption increased with immersion time at 23°C and 65°C, whereas the weight of the specimens decreased at 90°C. The moisture causes swelling at 23°C and 65°C and breakdown of chemical bonds between fiber and matrix at 90°C. It is observed that high temperature accelerates the degradation of the E-glass epoxy composite. At 90°C, the tensile strength of E-glass epoxy sharply decreased by 72.92% but no significant change was observed in modulus of elasticity of the composite.

The Bauschinger and Hardening Effect on Residual Stresses in an Autofrettaged Thick-Walled Cylinder

1986 ◽  
Vol 108 (1) ◽  
pp. 108-112 ◽  
Author(s):  
P. C. T. Chen
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Closed Form Solution ◽  
High Strength ◽  
Form Solution ◽  
Residual Stress Distribution ◽  
Hardening Effect ◽  
Reverse Yielding ◽  
Walled Cylinder ◽  
Elastic Unloading

Most of the earlier solutions for residual stresses were based on the assumption of elastic unloading and only a few considered reverse yielding. In this paper a new theoretical model for a high strength steel is proposed and a closed-form solution of residual stresses in autofrettaged tubes has been obtained. The new results indicate that the influence of the combined Bauschinger and hardening effect on the residual stress distribution is significant.

scholarly journals Experimentally validated dynamic results of a relaxation-type quarter car suspension with an adjustable damper

2017 ◽  
Vol 36 (2) ◽  
pp. 148-159 ◽  
Author(s):  
AN Thite ◽  
F Coleman ◽  
M Doody ◽  
N Fisher
Keyword(s):  
Shock Absorber ◽  
Ride Comfort ◽  
Damping Ratio ◽  
Closed Form Solution ◽  
Nonlinear Function ◽  
Frequency Domain Analysis ◽  
Form Solution ◽  
Damping Coefficient ◽  
Design Stage ◽  
Quarter Car

Models of varying degree of sophistication are used in vehicle dynamic studies. For ride comfort, Kelvin–Voigt arrangement is preferred and for impact harshness analysis, a relaxation-type suspension model, Zener or Maxwell type is used. The nonconsideration of relaxation-type models in ride comfort studies can result in significant errors for frequencies below ∼30 Hz. The object of the paper is to show the influence of the series stiffness on the effective suspension damping both experimentally and numerically. A frequency domain analysis of two-degree of freedom Zener quarter car model is performed to find the complex relation between effective damping coefficient and the limiting value of damping ratio for a given series stiffness. The nonlinear relation between shock absorber damping and the natural frequencies is clearly illustrated. A novel four-post rig set-up is used to validate the results by measuring transmissibilities, giving damping ratios for varying shock absorber settings. A closed form solution, based on a simplified partial model, of optimal damping coefficient, which is a nonlinear function of stiffnesses, shows good agreement with numerical simulations of the complete system. The nonlinearities in shock absorbers also influence the outcome. These findings can be a great value at early design stage.

scholarly journals STRENGTH PREDICTION OF DIFFERENT ORIENTATION UNIDIRECTIONAL GLASS FIBER LAP JOINTS

2012 ◽  
pp. 278-282
Author(s):  
R. SANTOSH ◽  
B. KIRAN
Keyword(s):  
Tensile Strength ◽  
Composite Materials ◽  
Glass Fiber ◽  
Structural Design ◽  
Software Package ◽  
Weight Ratio ◽  
High Strength ◽  
Lap Joints ◽  
Suitable Alternative ◽  
Robot Systems

Composite materials have made way to various fields, including aerospace structures, underwater vehicles, automobiles and robot systems. Due to the high strength to weight ratio of composites, they serve as a suitable alternative to metals, therefore making the need for a reliable database of structural design more important. Most of the modern civilian and military aircraft use composite materials for their primary structural components (in addition to metals). One of the key areas in composite structural design involves the tensile strength of joints. In the present work, the lap joints fabricated from different orientations of GFRP (Glass fiber reinforced polymer) specimens are subjected to tensile test. The effect of fibre orientation on the tensile strength of lap joint is investigated both experimentally and computationally using conventional software package. The experimental results are compared with FEA using conventional software package ANSYS.

scholarly journals Centrifugal stresses in arbitrarily laminated, rectangular—anistropic circular discs

1975 ◽  
Vol 10 (2) ◽  
pp. 84-92 ◽  
Author(s):  
C W Bert
Keyword(s):  
Composite Materials ◽  
Closed Form ◽  
Linear Theory ◽  
Closed Form Solution ◽  
Form Solution ◽  
Numerical Results ◽  
Current Interest ◽  
Elastic Plates ◽  
Organic Fibre ◽  
Anisotropic Elastic

The problem is formulated as one in the linear theory of thin, laminated, anisotropic elastic plates. A direct force-and-moment formulation is used, simplifying approximation is introduced and a closed-form solution is obtained. This solution exhibits bending-stretching coupling if the plate is asymmetrically laminated with respect to mass or stiffness or both. Numerical results typical of certain composite materials of current interest are presented. Specific laminates considered as examples include (1) glass—epoxy/steel, (2) cross-ply graphite—epoxy, and (3) various quasi-isotropic layups of organic fibre—epoxy.

Design and Analysis of Automotive Multi-Leaf Springs Using Composite Materials

2013 ◽  
Vol 372 ◽  
pp. 533-537 ◽  
Author(s):  
N. Suprith ◽  
K. Annamalai ◽  
C.D. Naiju ◽  
Arjun Mahadevan
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Commercial Vehicle ◽  
Weight Ratio ◽  
High Strength ◽  
Commercial Vehicles ◽  
Finite Element Approach ◽  
Leaf Springs ◽  
Element Approach ◽  
Solid Works

One of the oldest suspension components that are still in use, especially in commercial vehicles, is leaf springs. Due to high strength to weight ratio, the automobile industries have shown interest in replacing steel springs with composite leaf springs. This work is carried out on multi leaf springs having nine leaves, used in commercial vehicle. A Finite element approach for analysis of a multi leaf springs using ANSYS software is carried out. The model is generated using solid works and imported in ANSYS. The material of the leaf springs is 65Si7 (SUP9), composite leaf springs and hybrid leaf springs. Fatigue analysis of leaf springs is carried out for steel leaf springs, and Static analysis for steel leaf springs, composite leaf springs and hybrid leaf springs.

scholarly journals Design and Analysis of Composite Leaf Spring

2013 ◽  
pp. 209-212
Author(s):  
Y. N. V. Santhosh Kumar ◽  
M. Vimal Teja
Keyword(s):  
Composite Materials ◽  
Automobile Industry ◽  
Composite Structures ◽  
Weight Ratio ◽  
High Strength ◽  
Design Parameters ◽  
Leaf Spring ◽  
Metallic Structures ◽  
Conventional Steel ◽  
Fiberglass Composite

In these paper, composite structures for conventional metallic structures has many advantages because of higher specific stiffness and strength of composite materials is discussed. The automobile industry has shown increased interest in the replacement of steel spring with fiberglass composite leaf spring due to high strength to weight ratio. This work deals with the replacement of conventional steel leaf spring with a Mono Composite leaf spring using E-Glass/Epoxy. The design parameters were selected and analyzed with the objective of minimizing weight of the composite leaf spring as compar

scholarly journals Composite materials based on natural fibres applied for structural reinforcement

2022 ◽  
Vol 960 (1) ◽  
pp. 012007
Author(s):  
G Bou Abdallah ◽  
I Ivanova ◽  
J Assih ◽  
C Diagana ◽  
D Dontchev
Keyword(s):  
Composite Materials ◽  
Rapid Development ◽  
Weight Ratio ◽  
High Strength ◽  
Natural Fibre ◽  
Natural Fibres ◽  
Experimental Program ◽  
Existing Structures ◽  
Structural Reinforcement ◽  
External Reinforcement

Abstract Environmental problems and environmental protection triggered a rapid development of natural fibres as sustainable materials for the reinforcement of reinforced concrete structures. Synthetic fibre polymer composite materials have been widely accepted by the construction industries as an effective external reinforcement material to rehabilitate deficiencies in existing structures. These materials have exceptional performance such as high strength to weight ratio, corrosion resistance and lightness. However, the disadvantages include high costs during manufacturing and end-of-life services, less environmentally friendly and causing adverse effects on human health. This article presents an experimental program on the use of natural fibres as reinforcement in composite materials for structural strengthening. Different types of natural fibre fabrics (hemp, flax, mixed hemp and cotton) in terms of their mechanical properties were studied. The fibre and fibre fabric sheets were tested in tension test and compared with carbon and glass fibre fabric sheet as reference. So, this study carries out the effect of natural hemp and flax fibre fabric thickness on ultimate loads of specimens. In addition, the ultimate load and stiffness of strengthened beams were investigated. In fact, the results show that the reinforcement technique allows to increase the load-bearing of strengthened structure by 8% to 35% in bending tests.

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