scholarly journals Mechanisms of Origin and Classification of Out-of-Plane Fiber Waviness in Composite Materials—A Review

2020 ◽  
Vol 4 (3) ◽  
pp. 130
Author(s):  
Michael Thor ◽  
Markus G. R. Sause ◽  
Roland M. Hinterhölzl
Keyword(s):  
Composite Materials ◽  
Process Development ◽  
Influence Factors ◽  
Design Stage ◽  
Fiber Waviness ◽  
Load Carrying ◽  
Out Of Plane ◽  
Product And Process ◽  
The Impact

Out-of-plane fiber waviness, also referred to as wrinkling, is considered one of the most significant effects that occur in composite materials. It significantly affects mechanical properties, such as stiffness, strength and fatigue and; therefore, dramatically reduces the load-carrying capacity of the material. Fiber waviness is inherent to various manufacturing processes of fiber-reinforced composite parts. They cannot be completely avoided and thus have to be tolerated and considered as an integral part of the structure. Because of this influenceable but in many cases unavoidable nature of fiber waviness, it might be more appropriate to consider fiber waviness as effects or features rather than defects. Hence, it is important to understand the impact of different process parameters on the formation of fiber waviness in order to reduce or, in the best case, completely avoid them as early as possible in the product and process development phases. Mostly depending on the chosen geometry of the part and the specific manufacturing process used, different types of fiber waviness result. In this study, various types of waviness are investigated and a classification scheme is developed for categorization purposes. Numerous mechanisms of wrinkling were analyzed, leading to several recommendations to prevent wrinkle formation, not only during composite processing, but also at an earlier design stage, where generally several influence factors are defined.

An Approach to Classify Methods to Control Uncertainty in Load-Carrying Structures

2011 ◽  
Vol 104 ◽  
pp. 33-44 ◽  
Author(s):  
Roland Engelhardt ◽  
Jan F. Koenen ◽  
Matthias Brenneis ◽  
Hermann Kloberdanz ◽  
Andrea Bohn
Keyword(s):  
Present Article ◽  
Collaborative Research ◽  
Mechanical Engineering ◽  
Process Development ◽  
Holistic Approach ◽  
Research Centre ◽  
Load Carrying ◽  
Product And Process

Today, a wide variety of methods to deal with uncertainty in load-carrying system exists. Thereby, uncertainty may result from not or only partially determined process properties. The present article proposes a classification of methods to control uncertainty in load-carrying systems from different disciplines within mechanical engineering. Therefore, several methods were collected, analysed and systematically classified concerning their characteristic into the proposed classification. First, the classification differs between degrees of uncertainty according to the model of uncertainty developed in the Collaborative Research Centre CRC 805. Second, the classification differs between the aim of the respective method to descriptive methods, evaluative methods or methods to design a system considering uncertainty. The classification should allow choosing appropriate methods during product and process development and thus to control uncertainty in a systematic and holistic approach.

Resistless Patterning of Magnetic Storage Media Using Ion Projection Structuring

2001 ◽  
Vol 705 ◽  
Author(s):  
A. Dietzel ◽  
R. Berger ◽  
H. Grimm ◽  
C. Schug ◽  
W. H. Bruenger ◽  
...  
Keyword(s):  
Process Development ◽  
Ion Beam ◽  
Silicon On Insulator ◽  
Magnetic Storage ◽  
Magnetic Islands ◽  
Superlattice Structure ◽  
Head Positioning ◽  
Out Of Plane ◽  
Set Up ◽  
The Impact

AbstractCo/Pt thin film multilayers with strong perpendicular anisotropy and out-of-plane coercivities of 5-11 kOe were magnetically altered in areas of local ion beam interaction. The ion irradiations were performed by ion projection through silicon stencil masks fabricated by silicon on insulator (SOI) membrane technology. The ion projector at the Fraunhofer Institute for Silicon Technology (ISiT) was operated at 73 keV ion energy and with a 8.7- fold demagnification. After exposure to 3 × 1014Ar+/ cm2 magnetic islands smaller than 100 nm in diameter were resolved in the Co/Pt multilayersby means of magnetic force microscopy. The impact of different ion species (He+, Ar+ and Xe+) and ion energies (10 – 200 keV) on the multilayer structure was evaluated using Monte Carlo simulations. The ballistic interface intermixing was used to predict magnetic coercivity changes for various irradiation conditions. The simulations revealed that with 73 keV Ar+ and Xe+ ions the irradiation dose could be reduced by a factor of 100 and 400 respectively in comparison to 73 keV He+which was verified in the experiments. X-ray reflectivity measurements confirmed that the Co/Pt superlattice structure is slightly weakened during the irradiation and that the surface smoothness of the media is preserved. Using the Ion Projection Process Development Tool (PDT) at IMS-Vienna concentric data tracks including head positioning servo informations were patterned onto a 1” IBM microdrive™ glass disk which was coated with Co/Pt multilayers. In a single exposure step several tracks within an exposure field of 17 mm in diameter were structured by 2 × 1015He+/ cm2 at 45 keV using a 4- fold demagnification set-up.

Designing the Product Development Process

2007 ◽  
Author(s):  
Amanda Bligh ◽  
Manbir Sodhi
Keyword(s):  
Product Development ◽  
Process Design ◽  
Development Process ◽  
Process Development ◽  
Product Development Process ◽  
Time To Market ◽  
Quality Product ◽  
Development Processes ◽  
Product And Process ◽  
The Impact

Even though the literature on product and process development is extensive, not much attention has been devoted to categorizing the product development process itself. Existing work on product development processes such as Total Design, Integrated Product and Process Design among others advocate common approaches that should be followed throughout the organization, without any consideration of product characteristics. In this paper we review several existing development methodologies. Extensions of these are categorized by their applicability to different classes of products. We propose that development processes should be matched to product attributes and organization goals. Towards this end, we associate development processes along with their components such as House of Quality, Robust Design, TRIZ etc. with goals such as time to market, customer needs satisfaction, intellectual property generation, protection and exploitation, quality, product cost and others. We examine the impact of this association on the development process itself and propose guidelines for constructing specific processes associated with one or more goals. Tools and benchmarks for various applications are discussed, along with some case studies on the design of different development processes.

scholarly journals Classification of energy impacts by their effect on the structure and properties of reinforced reactoplasts

2021 ◽  
Vol 83 (2) ◽  
pp. 197-201
Author(s):  
I. V. Cheremukhina
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Polymer Composite ◽  
Polymer Composite Material ◽  
Polymer Chains ◽  
Polymer Composite Materials ◽  
Mesh Structure ◽  
Wave Nature ◽  
The Impact

The use of various physical influences is an economical and highly effective direction for regulating and improving the characteristics of the modified reinforced polymer composite materials developed in this work. The methods of energy effects studied in this work were used at the stage of impregnation of technical threads of various chemical nature with an oligomeric binder and a hardener (when preparing prepregs by the traditional method) or with a binder solution and a curing system (when preparing prepregs by the method of layered application of components) Based on the conducted research, a classification of the applied methods of physical modification according to the principle of the influence of energy fields is proposed. The studied methods of energy effects are divided into orienting and energetically energizing effects. The first group includes treatments with constant magnetic (PMP) or electric fields (PEP), and constant mechanical loads. The second group includes energy effects that have a wave nature (energetically energizing), and vibration, ultrasonic effects, and ultraviolet radiation are attributed to them. Modification methods of the first group contribute to a decrease in the mobility of binder molecules during curing, while the formation of branches of polymer chains occurs during the curing process, which leads to a predominant increase in the destructive stress during static bending. Energetically energizing effects contribute to the relative acceleration of the process of linear growth of polymer chains during curing, which is accompanied by the formation of a more sparsely cross-linked mesh structure, which leads to a predominant increase in impact strength. Of the two competing processes in the curing of epoxy oligomers, this one requires a higher activation energy, which is confirmed by the results of studies. Analyzing the results obtained, it can be concluded that the modification methods used in the work allow not only to obtain polymer composite materials with high strength characteristics, but also to directly adjust the properties of composites depending on the requirements for the products. Orienting modification methods lead to hardening of the resulting polymer composite material with a predominant increase in the destructive stress during static bending from 20 to 47%. When using energetically energizing influences in the technology of producing reinforced reactoplasts, the impact strength increases mainly from 19 to 40%.

Influence of Random Geometry on Effective Properties and Damage Formation In Composite Materials

1994 ◽  
Vol 116 (3) ◽  
pp. 384-391 ◽  
Author(s):  
M. Ostoja-Starzewski ◽  
P. Y. Sheng ◽  
I. Jasiuk
Keyword(s):  
Composite Materials ◽  
Effective Properties ◽  
Plane Elasticity ◽  
Brittle Behavior ◽  
Geometric Patterns ◽  
Composite Systems ◽  
Fine Mesh ◽  
Out Of Plane ◽  
Two Parameters

We study the effective moduli and damage formation in out-of-plane elasticity (i.e., two-dimensional conductivity) of matrix-inclusion composite materials with either randomly or periodically distributed inclusions (fibers). In this paper, we focus our attention on composites with isotropic phases, both of which have elastic-brittle response in damage. The elastic-brittle behavior is modeled with the help of a fine mesh finite-difference system, whereby damage evolution is simulated by sequentially removing/breaking bonds in this lattice in accordance with the state of stress/strain concentrations. The composite systems are specified by two parameters: stiffness ratio and strength ratio of both phases. In particular, we investigate the following aspects: basic classification of effective constitutive responses, geometric patterns of damage, varying degrees of randomness of the inclusions’ arrangements, and mesh resolutions of continuum phases.

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.

The Influence Factors Researching of Percentage of Load-Carrying Capacity Shared by Concrete for Large Section Concrete-Filled Rectangular Steel Tube Column

2011 ◽  
Vol 243-249 ◽  
pp. 370-373
Author(s):  
Xue Yi Fu ◽  
Na Xu ◽  
Hong Wei Jiao
Keyword(s):  
Carrying Capacity ◽  
Influence Factors ◽  
Steel Tube ◽  
Impact Factors ◽  
Load Carrying Capacity ◽  
Spring Stiffness ◽  
Large Section ◽  
Load Carrying ◽  
The Impact ◽  
The Relationship

Through the analysis of the transmission mechanism—distribution beam for large section (side length>800mm) concrete-filled rectangular steel tube column by the theory of elastic foundation beam we can obtain, percentage of load-carrying capacity shared by concreteis related with vertical spring stiffness of the steel tube, rotational spring stiffness of the steel tube, the vertical spring stiffness of the core concreteand stiffness of the distribution beam. Through analysis of the relationship among percentage of load-carrying capacity shared by concreteand the impact factors, we can identify the main factors that affect the percentage of load-carrying capacity shared by concrete, to control the design of the distribution beam.

scholarly journals CLASSIFICATION OF INFLUENCE FACTORS ON THE FORMATION OF TERRITORIAL SYSTEM MONODEVELOPMENT

2020 ◽  
pp. 38-45
Author(s):  
Nataliia Smochko
Keyword(s):  
Theoretical Study ◽  
Driving Forces ◽  
Influence Factors ◽  
Theoretical Research ◽  
Scientific Methods ◽  
Functional Aspects ◽  
General Scientific ◽  
The Impact ◽  
Territorial Systems

The purpose of this work is a theoretical study of a factor group influencing the formation of mono-development in socio-geographical systems, in particular the classification of factors according to the following criteria: degree of influence, nature of influence, level of influence and the impact of globalization on all groups. Methods. The study used general scientific methods, including analysis, scientific synthesis, analytical method, methods of comparison and generalization. The scientific novelty is that the article identifies different groups of factors of monodevelopment in territorial systems, which should be understood as a set of reasons for the formation of its unique properties, connections, relationships and driving forces of functioning, transformation in modern geospace. It has been revealed that objective factors of territorial system monodevelopment act as system-forming factors and directly influence the level of viability and viability of monosystem and its subsystems, determine differences of preconditions of monodevelopment of territorial system. It is manifested in territorial-component and territorial-functional aspects on the socio-economic, natural resource and demographic potentials of the territorial system. Practical meaning. The results of this study are the basis for scientific and theoretical research of the territorial system of monodevelopment, the methodological basis for revealing the features of formation, functioning and transformation (improvement, stimulation and regulation) of spatial structures in modern geospatial.

Integrated Product and Process Design for a Flapping Wing Drive Mechanism

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Wojciech Bejgerowski ◽  
Arvind Ananthanarayanan ◽  
Dominik Mueller ◽  
Satyandra K. Gupta
Keyword(s):  
Power Transmission ◽  
Transmission Efficiency ◽  
Flapping Wing ◽  
Point Of View ◽  
Design Stage ◽  
Molding Process ◽  
Drive Mechanism ◽  
Battery Capacity ◽  
Product And Process ◽  
The Impact

Successful realization of a flapping wing micro-air vehicle (MAV) requires development of a light weight drive mechanism that can convert the continuous rotary motion of the motor into oscillatory flapping motion of the wings. The drive mechanism should have low weight to maximize the payload and battery capacity. It should also have high power transmission efficiency to maximize the operational range and to minimize weight of the motor. In order to make flapping wing MAVs attractive in search, rescue, and recovery efforts, they should be disposable from the cost point of view. Injection molded compliant drive mechanisms are an attractive design option because of manufacturing scalability and reduction in the number of parts. However, realizing compliant drive mechanism using injection molding requires use of multipiece multigate molds. Molding process constraints need to be considered during the design stage to successfully realize the drive mechanism. This paper describes an approach for determining the drive mechanism shape and size that meets both the design and molding requirements. The novel aspects of this work include (1) minimizing the number of mold pieces and (2) the use of sacrificial shape elements to reduce the impact of the weld-lines on the structural performance. The design generated by the approach described in this paper was utilized to realize an operational flapping wing MAV.

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