Mechanical Response of High Performance Polymers: Abpbo, Abpbi and Abpbt

1992 ◽  
Vol 291 ◽  
Author(s):  
Tahir Çağin

ABSTRACTLight weight, high strength fibers and films produced from stiff chain polymers are good candidates for use as structural materials. Over the last decade, considerable success has been achieved in synthesizing high strength fibers and films. Due to their thermal and oxidative stability aromatic heterocyclic stiff chain polymers such as ABPBO, ABPBT, and ABPBI are especially good candidates. We first describe the finite theory of elasticity as applied in atomistic modelling and simulations of anisotropic solids and then use this description to investigate the mechanical response of these crystalline polymers as a function of applied hydrostatic pressure and uniaxial tension and compression along the chain direction in molecular mechanics simulations. In addition to these finite stress-strain experiments, I will also present the results of the first elastic stiffness matrix calculations performed on these high performance polymers.

2010 ◽  
Vol 56 (1) ◽  
pp. 3-18 ◽  
Author(s):  
A. P. Fantilli ◽  
H. Mihashi ◽  
P. Vallini ◽  
B. Chiaia

Abstract The ductility of High Performance Concrete (HPC) can develop both in tension and compression. This aspect is evidenced in the present paper by measuring the mechanical response of normal vibrated concrete (NC), self-compacting concrete (SC) and some HPCs cylindrical specimens under uniaxial and triaxial compression. The post-peak behaviour of these specimens is defined by a non-dimensional function that relates the inelastic displacement and the relative stress during softening. Both for NC and SC, the increase of the fracture toughness with the confinement stress is observed. Conversely, all the tested HPCs, even in absence of confinement, show practically the same ductility measured in normal and self-compacting concretes with a confining pressure. Thus, the presence of HPC in compressed columns is itself sufficient to create a sort of active distributed confinement.


1993 ◽  
Vol 305 ◽  
Author(s):  
W. Wade Adams ◽  
Ruth Pachter ◽  
Peter D. Haaland ◽  
Thomas R. Horn ◽  
Scott G. Wierschke ◽  
...  

AbstractNew polymers with exceptional properties are needed for applications in high-performance structures, novel electrical, optical and electro-optical devices, and for multi-functional smart materials. Concurrently, new computational capabilities and methods for properties prediction and analysis have enabled the study of a variety of polymer chain architectures to examine the principles that govern their high-performance properties. By semi-empirical and ab initio computational methods, flexible, stiff-chain, rigid-rod, and biological structures could be analyzed. Single chain molecular stress-strain curves for axial tension and compression were calculated, and the strain dependence of the molecular modulus and vibrational frequencies were compared to measurements of molecular deformation, such as IR and Raman spectroscopy. However, of special interest is the distinctly different response of alpha-helical biopolymer chains to strain. Indeed, in this study we compare on a theoretical basis the ‘spring-like’ microscopic mechanical response of alpha-helical biopolymers having a reinforcing intra-molecular hydrogen bonding network to analogous synthetic extended chain polymers, especially poly(para-phenylene terephthalamide) (PPTA) [KEVLARTM]. The theoretical verification of the absence of compressive buckling in alpha-helical biopolymer chains rationalizes the molecular elasticity and resistance to ‘kinking’ of those strands, manifested by the prevalence in Nature for coiled coils. The understanding of the structure-tofunction relationship in biopolymers explaining the role of the alpha-helix in these systems as a requirement for superior compressive mechanical properties, may enable new guidance for the synthesis of motifs consistent with molecular frameworks optimized by Nature.


Author(s):  
Sengshiu Chung ◽  
Peggy Cebe

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.


Author(s):  
A. L. Rusanov ◽  
L. G. Komarova ◽  
M. P. Prigozhina ◽  
V. A. Tartakovsky ◽  
S. A. Shevelev ◽  
...  

Alloy Digest ◽  
1973 ◽  
Vol 22 (9) ◽  

Abstract BERYLCO 25 is the standard high-performance beryllium copper alloy most widely used because of its high strength, hardness and excellent spring characteristics. BERYLCO 25 is the updated version of BERYLCO 25S (Alloy Digest Cu-3, November 1952). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-271. Producer or source: Kawecki Berylco Industries Inc..


Alloy Digest ◽  
1990 ◽  
Vol 39 (2) ◽  

Abstract ARMCO PH 13-8Mo is designed for high-performance applications requiring high strength coupled with excellent resistance to corrosion and stress corrosion. It has excellent toughness, good transverse properties and excellent forgeability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-224. Producer or source: Baltimore Specialty Steels Corporation. Originally published May 1969, revised February 1990.


Alloy Digest ◽  
2019 ◽  
Vol 68 (2) ◽  

Abstract Strenx 100 is a high-strength, high-performance structural steel with a minimum yield strength of 690 MPa (100 ksi). It meets the requirements of ASTM A514 Grade S. Strenx 100 is a US Customary steel similar to Strenx 700 (Alloy Digest SA-779, February 2017). This datasheet provides information on composition, physical properties, and tensile properties. Filing Code: SA-838. Producer or source: SSAB Swedish Steel Inc..


Alloy Digest ◽  
2016 ◽  
Vol 65 (2) ◽  

Abstract Outokumpu Type 630 is a martensitic age hardenable alloy of composition 17Cr-4Ni. The alloy has high strength and corrosion resistance similar to that of Type 304 stainless steel. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1238. Producer or source: Outokumpu High Performance Stainless.


1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.


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