News from the CMSC Laboratory

A new controller was installed on the TA Instruments thermal analysis station during the last quarter of 1992. The new controller, dubbed The Thermal Analyst 2200, is based on the IBM Personal System/2 Model 90 486 computer. The TA 2200 replaces the sluggish TA 9900 unit which used the 8088 chip. The TA Instruments thermal analysis station is capable of simultaneously executing differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and dynamic mechanical analysis. In addition to much faster speed of data analysis, the new unit brings upgrades in software as well. A listing of current software programs for thermal analysis is presented below:

The CMSC Laboratory is also equipped with a Perkin Elmer DSC 7 that has two kinetics programs as well as purity determination software.

In February, a laser extensometer was added to the United Testing Systems electromechanical screw drive test frame. Previously, tensile modulus was measured with a clip extensometer that attached to the tensile specimen. Because of their fragility, the clip extensometer required removal prior to coupon fracture which prevented collection of the full stress:strain behavior of the material. With laser extensometry, the entire specimen deformation through failure can be collected. The laser extensometer is fully compatible with all software on the UTS controller.

If you have question regarding thermal analysis or mechanical testing capabilities in CMSC Laboratory, please call Mike Rich at 353-4696.

Upcoming Conferences with the Society of Plastic Engineers

April 21 - 28: Hanover, Germany, Hanover Fair '93.

Call: Kurt Marttila (609) 987-1202.

April 25 - 28: San Francisco, California, SPI Structural Plastics Division Conference, Fairmont Hotel.

Call: Jack Murphy (202) 371-1022.

May 2 - 5: Boca Raton, Florida, SPI Sheet Producers Division Conference, Boca Raton Resort & Club.

Call: Allen Weidman (202) 371-5234.

May 6 - 12: Dusseldorf, Germany, Interpack '93

Call: Anne Meerboth (312) 781-5675.

May 10 - 13: New Orleans, Lousiana, SPE ANTEC, Convention Center/Hilton.

Call: Jeff Forger (203) 775-0471.

June 8 - 12: Kuala Lumpur, Indonesia, Plastics and Rubber '93.

Fax Willy Viethen 44 (071) 413 8277.

June 14 - 16: Schaumburg, Illinois, Plastics Recycling Conference, (SPE, Chicago Section and Recycling Division), Schaumburg Marriott Hotel.

Call: SPE at (708) 991-4629.

Implementing President Clinton's National Technology Policy

A reprint from SACMA-USACA's recommendations on implementing President Clinton's National Technology Policy

The U.S. advanced materials industry, as represented by SACMA (Suppliers of Advanced Composite Materials Association) and USACA (United States Advanced Ceramics Association) wholeheartedly endorses the six-point National Technology Policy promulgated by President Clinton. The Office of Science and Technology Policy, the U.S. Department of Commerce, Defense and Energy, as well as the National Center for Advanced Technologies, the Aerospace Industries Association of America and the Council on Competitiveness all have identified advanced materials as critical to maintaining the international competitiveness of U.S. manufacturing industries. SACMA and USACA advanced three material National Technology Demonstration and Utilization Initiatives focused on Surface Transportation, Public Works, and Commercial Aircraft. We believe these initiatives would provide the greatest impetus toward reaching the Clinton policy's broadly stated goal of "helping Americans [to] develop and quickly utilize new technologies," while building our nation's 21st century infrastructure.

INITIATIVE I

The national surface transportation network uses far more petroleum than any other sector of the American economy and is a major source of the "greenhouse gases" that effect the environment. A long term solution to this problem requires a comprehensive plan to develop and deploy new vehicular and mass transit systems (i.e., electric vehicles, Maglev, "intelligent highways", etc.) and improve existing ones (e.g., lighter cars).

The Lightweight Automobile Initiative

Goal: Increase auto fuel economy and decrease noxious emissions.

Means: Assist U.S. car companies in the adoption of advanced, lightweight materials and technologies.

INITIATIVE II

Based on the wealth of existing technology and since government is the customer, the application of advanced materials to public works construction and repair should be a prime initial target for partnerships among government, industry, and academia. Advanced materials have many advantages over traditional building materials and could extend the service life of both new and existing structures - bridges, highways, buildings, water and sewer systems, and other public works projects - thereby reducing costs and conserving energy resources. The knowledge and experience gained from the programs recommended here will spark other initiatives and increase investment in the broader civil engineering arena. The Federal government should allocate $200 million over the next four years to conduct such programs.

The Advanced Materials Bridge Initiative

Goal: Increase the safety and service life of new and existing bridge structures.

Means: Assist U.S. public works sector in the adoption of advanced materials technologies.

INITIATIVE III

Commercial aircraft is one of the few remaining positive contributors to the U.S. balance of trade. However, intense foreign competition and dedicated efforts on behalf of foreign government/industry teams threaten to erode this advantage. The application of advanced materials will be essential in developing next generation commercial aircraft capable of satisfying global consumer needs. Nonetheless, because of the costs and risks associated with the introduction of new technologies, commercial aircraft companies are reluctant to rapidly expand the use of advanced materials in new aircraft designs. To ensure that the U.S. remains the dominant force in the supply of commercial aircraft the following programs are recommended. The Federal government should allocate and additional $250 million over the next four years to support these programs.

The Lightweight Aircraft Initiative

Goal: Maintain U.S. preeminence in commercial aircraft.

Means: Assist U.S. aircraft industries in expanding use of advanced, lightweight materials technologies.

Center for Fundamental Materials Research Call for MRG-Type Proposals 1993-1994

The CFMR was established at MSU at the beginning of the fall term, 1985. Its purpose is to promote fundamental materials research on campus that will serve to enhance Michigan's economic development. Research supported by the center focuses on a relatively small number of "thrust areas" in a mode similar to that used at NSF Materials Research Laboratories. As these thrust areas mature and access other sources of funding, other research projects will be supported.

Proposals are invited for submission to the MSU Center for Fundamental Materials Research for funding in the 1993-94 academic year. There are three types of proposals to be funded by the CFMR during this period. These are: MRG-type proposals, multi-investigator proposals, and single-investigator proposals. Proposals in the latter two categories were the only types supported in previous years. The Center is soliciting pre-proposals for MRG-type grants. Multi and single-investigator proposals will be requested at a later date.

The CFMR currently funds projects in four major areas. These areas and the names of the individuals who coordinate their activities are indicated below. Information concerning these projects can be obtained by contacting the appropriate area coordinator or the Director, Brage Golding (355-9708.)

Area I: Layered Materials

Coordinator: Michael Thorpe (355-9279)

Area II: Small Structures and Surfaces

Coordinator: Brage Golding (355-9708)

Area III: Sensor Materials

Coordinator: Jeffrey Ledford (355-9715, ext. 208)

Area IV: Electronic, Photonic, and Magnetic Materials

Coordinator: James L. Dye (355-9715, ext. 288)

The submission procedure for an MRG-type proposal (with four or more investigators) consists of three procedures with different deadlines:

Step 1: Submission of a proposal no longer than 4 pages.

Deadline April 2, 1993 5:00 p.m., rm. 435 Chemistry Bldg.

Step 2: Oral presentations of the MRG-type proposals (open to all CFMR faculty members.) The CFMR Advisory Committee will invite groups to submit full proposals.

Deadline April 10, 1993 time and place to be announced

Step 3: Full proposals due

Deadline May 14, 1993 5:00 p.m., rm. 305 Physics

All proposals must be double spaced, printed in no smaller than 12 point font, and utilize one inch margins. For more information on the content of submission materials, please call the Composite Center at (517) 353-5466.

The 9th Annual ASM/ESD Advanced Composites Conference and Exposition

The 9th Annual ASM/ESD Advanced Composites Conference and Exposition (ACCE), sponsored by ESD, the Engineering Society and ASM International, will provide a dynamic forum for the exchange of structural composite technology among the automotive and commercial transportation, aerospace, defense, marine, and recreational industries. The 1993 program will include tutorials and technical sessions addressing design, materials science and other related topics within the composites industry. Papers will be published in the conference proceedings, which will be distributed at the event.

Abstract Submission

The 100-200 word abstract should include a description of the content, conclusions and significance of the paper; proposed title of the paper; authors (and any co-author's) name, company, complete address, telephone and fax numbers. Proposed topics include design methods for composites, materials science and engineering, liquid molding, fiber preforming, pultrusion, process automation and control, recycling of composites, composites coatings, tooling for composites, fiber/matrix interfaces, and noise and vibration control. Abstracts should be submitted no later than April 23, 1993 to:

ESD Conferences

2350 Green Rd., Ste. 190

Ann Arbor, MI. 48105

Phone: (313) 995-4440

Fax: (313) 663-7835

All authors will be notified of accepted papers by May 6, 1993. Manuscripts submitted for inclusion in the proceedings must be received by ESD no later than July 1, 1993. Please contact the Composite Materials and Structures Center at 353-5466 for a copy of the abstract submission form.

Composite Center Joins the Navy!

The CMSC has completed a membership agreement to join the Great Lakes Composites Consortium (GLCC) as a "partner". The GLCC is a US Navy funded Center of Excellence for Composites Manufacturing Technology. Its primary focus is to solve problems in reducing manufacturing process costs, maintenance and repair, non-destructive testing and design for manufacturing. As such it maintains an industry consortium which sets a technical agenda in consultation with the Navy Manufacturing Technology program. Member firms (including Universities and their faculty) can conduct funded research under approved topics. One unique capability of the GLCC is its "teaching factory" which is scheduled to open soon in Kenosha, Wisconsin. This facility will be set up to train personnel in the manufacture of composite materials. These are 4 Principal Members in the GLCC: Grumman Corporation, Northrop Corporation, McDonnell Corporation and Rockwell International Corporation. 10 Supporting Members and 31 Associate Members and Partners make up the rest of the consortium. Announcements of forthcoming research opportunities will be made through the CMSCourier.

Elastic Behavior of Composite Materials

Funded by the Research Excellence Fund

The properties of composite materials can be tailored to optimize the design of objects as diverse as tennis racket frames and aircraft wings. The design process is often carried out empirically, based on prior experience and/or theoretically by using either analytical or numerical methods. The calculation of the effective properties of composite materials is a complex problem, since there are many factors which influence these properties: the material constants of constituents, the shape, size, and geometric arrangements of reinforcement, the boundary conditions between the reinforcing fibers (inclusions) and the remaining material (matrix), and other.

In our study we are interested in theoretical prediction of the local stress fields and of the effective elastic properties of composites. Our approach has been to use the knowledge base from mechanics, involving the solution of various simple geometries and the subsequent development of effective medium theories, and from physics which has developed new methods to deal with randomness at the atomic level. We have put these two approaches together in a cross disciplinary effort to try to better predict the elastic behavior and failure modes of composites.

We have developed a computer program of finite difference type to study tranverse cross-sections of an unidirectional fiber reinforced composite containing hundreds of fibers. Using these simulations we can calculate "exactly" both the local and the effective properties of composites. We focus on the random geometric arrangement of fibers since the random distribution is least understood and it most closely represents the geometry of a typical unidirectional composite. Also, it is almost intractable by using finite or boundary element methods because the average over many Monte Carlo generated samples is required to obtain meaningful statistics. The advantage over our scheme is a fixed mesh, while remeshing would be required for finite and boundary element approaches. An improtant aspect of our numerical work is the ability to produce stress contour maps, from which the high stress areas can be visually observed and the critical paths identified. From these the damage initiation and propagation can be studied. The "damage" means either plastic yielding or cracking.

From these simulations we have been able to understand when certain approximate and commonly used effective medium theories are applicable and when they are not. As a result of these computer simulations, some new powerful theorems have been developed that describe the properties of these composites. One such intersting result is that the effective area elastic modulus of a material containing holes is independent of Poisson's ratio of the matrix. Now, we are beginning a study of composites with inclusions having sharp corners by using conformal mapping and computer techniques.

In addition, this work is leading to a better understanding of different failure modes, and in particular to a very simple model for the stress distribution under hydostatic loading. Under hydrostatic loading, the stresses are concentrated in the narrow regions (necks) between fibers and are largely determined by the local geometry. In contrast, under uniaxial loading, the regions of large stress are determined by longer range cooperative effects and are therefore much harder to predict from the geometry of the fibers.

It is hoped that this work will soon find practical use in the industrial design of composites. Collaborations have begun with Ford Motor Company Research, who are providing a partial financial support for this work, and with Armstrong World Industries, Inc.

Selected references for further reading:

Materials Available for Education and Research

The CMSC has obtained a large amount of material that can be used for educational and research projects. At this time, the Center has 600 pounds of sized AS4 carbon fibers on nominal 4 pound spools. Also available is several hundred pounds of carbon fiber/epoxy unidirectional prepreg. Contact Mike Rich at (517) 353-4696 for additional information.

Nondestructive Evaluation of Composite Material by Ultrasonic Techniques

By B. Ho (Associate Professor, Electrical Engineering), R. Zapp (Associate Professor, Electrical Engineering), E. Sheu (Graduate Assistant, Electical Engineering), B. Hsu (Graduate Student, Electrical Engineering)

Funded by the Research Excellence Fund

Composites, or fiber reinforced materials, are inherently inhomogenous due to the fabrication process, environmental exposure and handling damage. In the auto and aerospace industries, they are subjected to intense structural demands. In order to evaluate reliability, ultrasonic nondestructive testing can provide valuable information about the mechanical properties of the sample.

In the past few years, we have developed ultrasonic imaging techniques which greatly improve range resolution. The techniques employ high frequency sampling of the r.f. echo for amplitude and phase processing. A laboratory microprocessor controlled ultrasonic imaging system has been built and operated. A second portable imaging system is under construction for on-site inspections. The range resolution achievable approaches the theoretical limit of an operating wavelength (the wavelength is 0.67mm at an operating frequency of 2.25 MHz). Higher resolution can be realized by increasing the operating frequency and the corresponding sampling frequency. Currently, a 40 Mega samples per second system is in use, with a range resolution of approximately 0.5 mm.

In a fiber reinforced composite the fiber-matrix gives fiber composites their structural integrity. It is at the layer interfaces where manufacturing defects develop because of the differences between thermal expansion coefficients of reinforcement and matrix. These defects cause local high stress concentrations and serve as sites for damage initiation and progression. However, depending upon the loading conditions certain manufacturing defects may not be critical. They may not grow in size during the life cycle of a composite structure. On the other hand, other defects may grow with applied load and cause reduction in the load carrying capacity. Although fiber-reinforced matrix composites laminates have a high stiffness-to-weight ratio, they are susceptible to transverse low-velocity impact. Depending on the extent of the damage, the strength of the materials can be significantly reduced. Conventional techniques for detecting impact damage include edge-replication, x-ray and ultrasonic imaging. Only the ultrasonic method can be classified to be truly nondestructive.

Most imaging systems for material characterization are based on pulse echo data. The quality of the image is limited by the coupling and the attenuation of the acoustic signal. We have developed a technique to detect the attenuation profile of the material. By using both the reflections and the transmissions from transducers placed on opposite sides of the sample we can uniquely determine the attenuation profile. Such imaging provides information on the homogenity of the material structure as well as on nonlocalized damage.

Monitoring and controlling temperature profiles in material processing is very critical to the success of the product. Present techniques for temperature monitoring require semiconductor sensors such as thermistors of thermocouples. These are invasive in nature. Noninvasive techniques such as use of ultrasonics have been proposed as a means to monitor and characterize temperature changes in material. However, previous sensitivities and accuracies were rather poor due to limited measurement capabilities. With our improved time resolution (velocity accuracy), we are able to profile the temperature in layered materials.

In a conventional ultrasonic imaging system, either mechanical or transducer array scanning is used. Many technical difficulties are encountered in those scanning methods. Consequently, a truly real-time, instantaneous imaging was not possible. Recently, we have been developing an imaging system without any scanning mechanism by diffracting a laser beam from an ultrasound beam. Synchronized pulsing of both beams is required. A preliminary analysis of the second order Bragg's diffraction has been carried out. The results indicate that it is possible to obtain a cross- sectional view of various depths from the surface of the target. The ultrasonic techniques developed here can easily be transferred to other areas such as biomedical and seismic applications.

CMSC Joins the Army

The CMSC has just agreed to enter into a cooperative research and development agreement (CRADA) with the Army Tank Automotive Command (TACOM) located in Warren, Michigan. This agreement allows the CMSC and MSU faculty to use equipment and facilities at the TACOM facility. As a direct result of this agreement a Liquid Controls Resin Transfer Molding System has been transferred to the CMSC to be used in the fabrication of thick section 3D composite panels for ballistic testing. In exchange for the fabrication of these panels, students and faculty have use of the equipment for composite liquid molding research.

CMSC Post-Doctoral Research Associate Position

After three years of outstanding contributions to the CMSC, Dr. Pedro Herrera-Franco has left the CMSC to return to Mexico. Pedro has contributed immensely not only in research but in the training and supervising of students on mechanical testing of composite materials. The CMSC is now seeking a qualified candidate to fill the position of research associate in composite experimental mechanics.

Position Requirements: Ph.D. degree with major field in Mechanics, or Materials Science and/or Engineering. Previous experience as a postdoctoral research associate is desirable. Candidate must have training in both micromechanics and macromechanics as well as experience in the experimental mechanics of composite materials and ability to operate mechanical and hydraulic materials testing machines. Experience in photoelastic methods for strain measurement is desirable. Finite element and/or finite difference methods capability is necessary. The candidate must have a publication record indicating facility in the named areas.

The candidate will be expected to conduct research on various polymeric, metallic and ceramic composites using standard ASTM or related experimental test methods for measuring static and dynamic mechanical and fracture properties at variable temperature and humidity conditions. The candidate will be expected to participate in a collaborative program exploring the relationship between fiber-matrix adhesion and composite properties. Familiarity with fiber-matrix adhesion measurement methods will be expected. The candidate will be expected to prepare research proposals as well as interpret, analyze and present the results of this research for publication in the archival literature, technical reports and presentation at national meetings.

For more information contact Professor L.T. Drzal at the Composite Center, (517) 353-5466.

Important REF Funding Information

The next REF funding cycle will begin on July 1, 1993 instead of the usual October 1st start date. The Request for Proposals will be issued around April 15th with proposals due by May 15th. It is anticipated that the reviewing cycle will be completed and funding announcements will be made by June 15th. This is an opportunity for renewal of existing projects (depending on progress) and initiation of new projects. The highest priority in funding will be given to proposals having commitments for matching funds from industrial or government sources.

CMSC Faculty Publication List

The last component of the new CMSC brochure is now available. A yearly listing of publications by students and faculty has been compiled and published as a separate pamphlet in the CMSC brochure. This listing covers all publications arranged chronologically and grouped by years from 1989 to 1992. It is anticipated that this listing will be continually updated yearly. Over this four year period, over three hundred publications have been made. Copies are available on request from the CMSC office, (517) 353-5466.

Calendar of Events

April 1993

American Institute of Aeronautics of Astronautics - Introduction and Methodology of Space Cost Engineering,

Washington, DC

Dates: 4/28-30/93

Society of Manufacturing Engineers - Manufacturing and Fabrication of Composite Parts

Los Angeles, California

Dates: 6/14-15/93

Society of Manufacturing Engineers - Resin Transfer Molding (RTM) Tooling and Manufacturing Course.

Los Angeles, California

Dates: 6/16/93

First Biomass Conference of The Americas: Energy, Environment, Agriculture, and Industry (Provide a national and international forum to support the development of a viable biomass industry.)

Burlington, Vermont

Dates: 8/30-9/2/93

Abstract due: 3/1/93

Paper due: 6/1/93

U.S. Department of Energy - Tenth International Symposium on Alcohol Fuels (examine scientific and technical advances for the use and production of alcohol fuels)

Colorado Springs, Colorado

Dates: 11/7-10/93

Abstract due: 3/31/93

Paper due: 7/15/93

Materials Research Society -Technical Symposia, Short Courses, Equipment Exhibit and Table-Top Display (Each symposium will provide a forum for scientist and engineers to exchange information and ideas at the forefront of materials research.)

Boston, Massachutes

Dates: 11/29-12/3/93

Abstract due: 6/20/93

Society of Manufacturing Engineers "Tooling for Composites '94" Conference and Exhibit

Anaheim, California

Dates: 1/17-20/94

Abstract due: 4/26/93

Composite Materials and Structures Center
College of Engineering
Michigan State University
East Lansing, MI 48824-1326

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