The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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This paper describes a mesoscopic approach of using beam and shell
finite elements to model the forming of composite parts using an
SMC woven fabric. Nonlinear constitutive models are implemented
in ABAQUS/Explicit via user-defined material subroutines to describe
the shear and tensile mechanical behavior of the woven fabric.
Both single-ply and multiple-ply layups are modeled.
Saturated- and unsaturated-polyester resins containing glycols made
from renewable or recycled sources are being developed as a way
to become less dependent on petroleum-based glycols. In this study
SMC performance of standard-density Class A automotive SMC
containing polyester resins produced from petroleum-based glycols was
compared to standard-density Class A automotive SMC containing
polyester resins produced from renewable-source glycols. The evaluation
included processing aesthetics and adhesion performance. Finally a
new low-density Class A automotive SMC containing polyester resins
produced from renewable-source glycols will be introduced.
Research on the use of soybeans to produce polyurethane polyols
unsaturated polyester resins and thermoplastic fibers has been funded
by the United Soybean Board (USB). The USB funds a wide range of
activities including research and development of new industrial products
made from soy. These developments have resulted in new patented
technology. Commercialization of this technology has resulted in the
production of unsaturated-polyester resins for fiberglass-reinforced
composites and urethane polyols for polyurethane foams. The commercial
applications of these bio-based polymers are found in a wide range
of applications in the transportation markets.
In order to advance the commercialization of natural fiber reinforced
plastics for automotive use a partnership was formed between
academia natural fiber processor material supplier and OEM.
This partnership improved the communication along the supply chain
and resulted in optimized material properties to meet OEM specifications
and application part performance. Several products have been
developed that meet current material specifications offer significant
weight savings over conventional mineral- and glass-reinforced composites
and are competitively priced.
External trends have continued to drive end users in consumer
and industrial applications to seek renewably sourced and sustainable
solutions to use in more and more demanding applications. To meet
this need a portfolio of renewably sourced engineering materials
was developed. The products are designed to provide performance
and functionality equivalent to or better than today’s petroleumbased
materials while reducing the environmental footprint.
The portfolio includes glass-reinforced thermoplastic grades for
high strength and stiffness.
A unique approach to toughening thermosets has been identified by
introducing small amounts of amphiphilic block copolymer. The result
is a good viscosity-Tg-toughness balance. In this work the fracture
behavior of these modified epoxies was carefully studied in an attempt
to understand the toughening mechanisms that exist. The findings
suggest that cavitation in even these nano-sized spherical micelles is the
primary mechanism of toughening. These findings were also found to
be a strong function of the cross-link density of the host network with
higher levels of plastic deformation at the crack tip being observed in
the low-cross-link density systems. Glass-fiber-reinforced composites
made with epoxies modified with these toughening agents were found
to have improved fatigue resistance.
In today’s environment there is an ever-increasing desire to ‘circle the
square’ reaching high-performance durability light weight and manufacturing
flexibility without increasing and even trying to lower overall
system costs. This presentation will discuss a new enabling technology
platform engineered towards these ends: cross-linked thermoset acrylics.
These are non-flammable zero-emission systems that contain no volatile
or hazardous components at any stage of their life cycle. They are easy
to use in molding processes and ideally suited for today’s ‘greener’ lightweight
automotive composites. Their application in natural fiber
composites will also be outlined in the presentation.
The direct process of producing long-fiber-reinforced thermoplastics
(LFT-D) is highly innovative and economical for producing semi-structural
and structural components as well as cosmetic parts with grained
surfaces. The advanced plastic-hybrid developments with tailored LFT
and E-LFT technologies fulfill crashworthiness requirements. Similiarly
the direct processing of fiber-reinforced thermosetting materials – direct
strand molding compound (D-SMC) – is focused on the reproducible
manufacturing of the compound resulting in a constant part production
at a high level minimizing material costs and expensive post-mold operations
and paint processes as well as reducing logistical costs. The high
flexibility in composing the recipe in selecting the resins fillers and reinforcements
result in the high degree of freedom of this process.
Joining is often one of the critical steps in the fabrication of composite
products. However the low polarity and inert characteristics of
polypropylene composite surfaces cause many problems in the assembly
of these composites with dissimilar materials. In order to overcome the
adhesion issues an epoxy-based primer was developed and the compatibility
of several commercial adhesives with the primer was evaluated.
Results showed very-good lap-shear strength of up to 15 MPa with
substrate failure. The performance of the primer was also evaluated
between -30 and 80°C and after conditioning in humidity. While lapshear
strength decreased with increasing temperature it remained
unchanged after conditioning. Finally different practical approaches to
apply the primer film to a polypropylene continuous-fiber composite
were investigated including techniques to apply the primer during and
after composite consolidation.
The moulding system FIBRETEMP describes a procedure to heat
moulding surfaces efficiently with a consistent distribution of temperature.
The heart of this invention the use of carbon fibres to conduct
electricity as well as integrating the heating element and the structure
within the surface to be heated. These moulds are highly energyefficient
and extraordinarily dimensionally stable while also being
produced at low cost. This technology has already been proven in
manufacturing composite parts and has nearly halved cycle time for
some applications due to its efficient heating characteristics.
The relationship between the resin and fiber properties in polypropylene
long fiber thermoplastics is further analyzed in the second part of
this work. The properties of the maleic anhydride grafted polypropylene
additives (coupling agents) are studied and correlations between
the maleic anhydride content melt flow and base polymer used is
presented. Polypropylene long fiber thermoplastics pellets were
compounded with various coupling agents. The materials were then
molded and tested. The results of the study are presented.
While numerous advances have been made in the manufacturing
methods of long-fiber thermoplastics (LFTs) their dynamic response in
terms of fatigue and vibration damping has been a subject of limited
study. There is presently no standardized design information for a
composites / automotive designer for use of LFTs in situations of longterm
fatigue and vibration. The behavior of E-glass fiber / polypropylene
LFT composites has been characterized for their fatigue behavior and
vibration response in the present study. The work provides an understanding
of the influence of extrusion / compression-molded long fibers
and the fiber orientation that is generated during their processing.
Results will be useful to designers in accounting for fatigue life and
damping factors.
The deterioration of macroeconomic conditions has severely impacted
automotive production and the autoplastics supply chain. Thermoplastic
composites – especially long-glass-fiber versions – will benefit from
these conditions via the development and implementation of new resin
and compound technology as well as advances in fabrication technology
adapted to the requirements of a new automotive paradigm and new
applications. Our outlook is for gains in high-performance long-glass
(and other fiber) reinforced-PP compounds in competition with shortglass
and mineral-filled compounds.
For over 50 years the auto industry has been gradually replacing steel
with plastics and molded composites. Substantial progress has been
made particularly in applications where significant parts consolidation
is possible using composites. The need is greater than ever for further
substitution of composites for steel but large performance gaps
between steel and composites limit the rate of progress. Current
gap factors include: stiffness and strength molding thickness process
cycle time ability to weld to steel and cost. This presentation will
address approaches for eliminating each of these gap elements for
non-appearance parts using a systems approach based on new
thermoplastic composite technologies.
Composite parts made from long-fibre-reinforced thermoplastic (LFT)
material systems are known for their high impact and tensile strength.
And due to the benefits of the outstanding price to performance relationship
of the in-line compounded (ILC) direct-LFT (LFT-D) technology
used for production of composites based on the use of polypropylene
and glass fibres it has achieved consistently more applications in the
automotive industry. But LFT-based automotive applications are mainly
used for parts with large surfaces which can contribute significantly to
the total amount of VOCs and odor inside a car. The current work
explains a feasible approach of using commercial additives – provided as
a complete system – in combination with VOC- and odor-reducing
additives to further enhance the mechanical and outgasing properties of
the PP / GF composites produced by LFT-D / ILC technology.
Fast and cost-efficient design of higher quality lighter and more energy
efficient vehicles is one of the key success factors for today’s automotive
industry. Predictive CAE and the use of composites materials offering
good weight to mechanical-performance ratio are two ingredients that
will help the industry moving forward profitably. We will introduce the
DIGIMAT nonlinear micromechanical-modeling technology which can be
used to predict the nonlinear behavior and failure of multi-phase materials
based on their underlying microstructure (e.g. fiber content fiber orientation
fiber length etc.). The multi-scale material-modeling process used to
model the reinforced plastic part will then be presented.
An integrated approach linking process to structural modeling has been
developed to predict the nonlinear stress-strain responses and damage
accumulations in injection-molded long-fiber thermoplastics (LFTs).
The approach uses Autodesk® Moldflow® Plastics Insight’s fiber orientation
results predicted by a new fiber-orientation model developed for
LFTs and maps these results to an ABAQUS® finite-element mesh for
damage analyses using a new damage model for LFTs. The damage
model which has been implemented in ABAQUS via user-subroutines
combines micromechanical modeling with a continuum damagemechanics
description to predict the nonlinear behavior of LFTs due to
plasticity coupled with damage. Experimental characterization and
mechanical testing were performed to provide input data to support
and validate both process modeling and damage analyses.
Dielectric cure monitoring has been used in thermoset laboratories for
decades to characterize materials. Historically attempts to take the
technology to the production floor where the benefits can be
maximized in production tools have failed due to shortcomings in
sensor durability and system reliability. Breakthroughs in dielectric
sensor design have resulted in the development of durable in-mold
sensors that can operate on the production floor. Thermoset molders
can now “see” changes in flow and cure inside their production tools
allowing automatic “real-time” adjustments for process variation and
enabling significant gains in productivity and quality. Benefits to compression
and injection molders include: 10-25% reductions in cycle time
improvements in quality and reduction of scrap and a better understanding
of flow and cure rates inside the mold.
Often times a composite component can be used to replace a metallic
component providing a significant reduction in weight while providing
little or no loss in strength or stiffness. For automotive engineers to
further utilize composites in new applications it is important to
understand the mechanical behavior of the material in all the critical
loading directions. This paper focuses on the relevant tests necessary
to characterize the mechanical properties of a pultruded carbon fiber
composite material. The mechanical properties evaluated include
tension compression interlaminar shear and fatigue testing in the fiber
direction. Included is a discussion on key aspects of the testing in order
to ensure reliable results. Also a set of design criteria is developed for
the use of the material according to the measured properties.
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
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