Plastics failure analysis

S. Ding, M.T.K. Ling, A. Khare, and L. Woo, Activation energies of polymer degradation. In J. Moalli (Ed.), Plastic Failure Analysis and Prevention, Plastics Design Library, Norwich, NY, 2001, pp. 219-225. 

Mohomed, K. Bohnsack, D.A. Differential scanning calorimetry as an analytical tool in plastics failure analysis. Am. Lab., 3, 45, 2013. 

Wulpi, D. J., Understanding How Components Fail, 2nd Edition, ASM, 1999. Wypych, G., Plastics Failure Analysis and Prevention, PDL, 2001. 

Moalli J. Plastics failure analysis and prevention. Norwich, NY William Andrew Publishing/ Plastics Design Library 2001. Available from http //knovel.com/web/portal/browse/display EXT KNOVEL DISPLAY bookid-382 VerticalID-0. 

Ezrin M, Lavigne G. Gas chromatography/ mass spectroscopy for plastics failure analysis. Paper presented at ANTEC, Chicago 1991. 

THE ROLE OF ANALYTICAL AND PHYSICAL METHODS IN PLASTICS FAILURE ANALYSIS... 

There is no shortage of analytical and physical methods for plastics failure analysis. The keys to successful utilization are an understanding of their strengths and limitations, and intopretation of results in the light of polymer science and technology. 

Plastics failure analysis, analytical methods in plastics failure analysis, physical m ods in plastics failure analysis. 

There is the microtoming optical analysis test. In this procedure thin slices (under 30 tixri) of the plastics are cut from the product at any level and microscopically examined under polarized light transmitted through the sample. Rapid quality and failure analysis examination occurs by this technique. This technique has been used for many years in biological studies and by metallurgists to determine flaws, physical and mechanical properties. Examination can be related to stress patterns, mechanical properties, etc. 

The acoustic microscopy s primary application to date has been for failure analysis in the multibillion-dollar microelectronics industry. The technique is especially sensitive to variations in the elastic properties of semiconductor materials, such as air gaps. SAM enables nondestructive internal inspection of plastic integrated-circuit (IC) packages, and, more recently, it has provided a tool for characterizing packaging processes such as die attachment and encapsulation. Even as ICs continue to shrink, their die size becomes larger because of added functionality in fact, devices measuring as much as 1 cm across are now common. And as die sizes increase, cracks and delaminations become more likely at the various interfaces. 

PLASTEC is one of 20 information analysis centers sponsored by the Department of Defense to provide the defense community with a variety of technical information services applicable to plastics, adhesives, and organic matrix composites. For the last 21 years, PLASTEC has served the defense community with authoritative information and advice in such forms as engineering assistance, responses to technical inquiries, special investigations, field trouble shooting, failure analysis, literature searches, state-of-the-art reports, data compilations, and handbooks. PLASTEC has also been heavily involved in standardization activities. In recent years, PLASTEC has been permitted to serve private industry. 

Failure during peel is occurring cohesively in the plastic. SEM analysis shows fractured plastic on both the polyetherimide and metal side of the peel for both ULTEM 1000 (Figure 14) and ULTEM 2312 (Figure 15). Glass fibers can also be found on the metal side of the peel for ULTEM 2312. 

S. Okikawa, M. Sakimoto, M. Tanaka, T. Sato, T. Toya, and Y. Kara, Stress Analysis of Passivation Film Crack for Plastic Molded LSI Caused by Thermal Stress, Proc. Internet ional Society for Testing and Failure Analysis, Oct. 1983, Los Angeles, CA. 

Acta Metallurgica et Materialia Cement and Concrete Research Composite Structures Computers and Structures Corrosion Science Engineering Failure Analysis Engineering Fracture Mechanics European Journal of Mechanics A B International Journal of Fatigue International Journal of Impact Engineering International Journal of Mechanical Sciences International Journal of Non-Linear Mechanics International Journal of Plasticity... 

Polymers are often used in conjunction with other materials as composites. The most familiar types are the fiber-filled composites such as fiberglass and the carbon-, boron-, or Kevlar-filled advanced composites. Granular-filled composites such as those using clay as extenders in some plastics or ground quartz added to dental plastics to increase their wear resistance also represent an important class of materials. In these cases the presence of a second phase as well as the interface between polymer and filler increases the complexity of the failure analysis. 

Failure of parts, irrespective of plastic t5 e, is an inevitable fact of the operation of chemical plants. Fluoropolymers are no exception in spite of their excellent chemical, thermal, and mechanical properties. These plastics form the processing surfaces of equipment where they are exposed to the most aggressive and corrosive chemicals. The repeated exposure of fluoroplastics to these chemicals, in addition to other factors, can affect the integrity and surface quality of the parts. The chapters dealing with properties and part fabrication techniques of fluoropolymers should be consulted extensively. An understanding of the limitations of fluoropolymers and flaws created by fabrication methods is required for successful failure analysis of parts. 

External loads are imposed on a bonded joint or structure by the dead weight of the structure and its contents, accumulated snow, wind, and people. The average stresses in a joint created by these loads can be calculated from structural analysis, but the maximum stress at joint edges is more difficult to determine. These stresses have been examined in some detail. Discussions by Walsh and others [63] and Glos and Horstmann [40] of the effects of external forces on the stresses in bonded wood lap joints are notable. Walsh and others applied plastic failure and fracture mechanics criteria to study the effects of the ratio of lap length (T) to primary member thickness (T) on the average failure stress of... 

Von Mises stress is originally formulated to describe plastic response of ductile materials. It is also applicable for the analysis of plastic failure for coal undergoing high strain rate. The von Mises yield criterion suggests that the yielding of materials begins when the second deviatoric stress invariant J2 reaches a critical value. In materials science and engineering the von Mises yield criterion can be also formulated in terms of the von Mises stress or equivalent tensile stress, a scalar stress value that can be computed from the stress tensor ... 

A particular distinction between the mechanical behaviors of metals and plastics (URPs and RPs) is explained in order to avoid a possible confusion that could have arisen from the preliminary review. A typical stress-strain curve for a metal exhibits a linear elastic region followed by yield at the yield stress, plastic flow, and ultimately failures at the failure stress. Yield and failure occur at corresponding strains, and one could define yield and failure in terms of these critical strains. This is not common practice because it is simpler in many cases to restrict step (a) to a stress analysis alone. By comparison, it may appear strange that it was stated that plastics failure criteria are usually defined in terms of a critical strain (rather than stress) and, by comparison with the metals case, switching back from strain to stress may appear to be a minor operation. 

Ottenbrite RM, Kim SW (2001) Polymeric drugs and drug delivery systems. CRC, Boca Raton Piggott M (2002) Load bearing fibre composites. Kluwer Academic, Dordrecht Portnoy RC (1998) Medical plastics degradation resistance and failure analysis. Society of Plastics Engineers, USA... 

V. Shah, Handbook of Plastics Testing and Failure Analysis 3rd ed Expanded ed. Wiley-Interscience Hoboken, NJ, 2007. 

A. Lustiger, Understanding Environmental Stress Cracking in Polyethylene, in Medical Plastics Degradation, Resistance Failure Analysis ed. R.C. Portnoy (SPE, Plastic Design Library, Rice RC, Tritsch DE, 1998), pp. 66-71... 

---