Small punch test

High-Temperature Ductility of TiC as Evaluated by Small Punch Testing and the Effect of CraCi Additive... 

Recently, a modified small punch testing (MSP) method has been developed for mechanical evaluation of ceramic and ceramic/metal composite materials used in FGMs [5]. In the present study, the MSP method was applied to evaluate TiC-based ceramics, which are employed as ceramic-side materials in a TiC/Ni3Al FGM. Because the TiC/Ni3Al FGMs apparently show different damage behavior at temperatures from 1208 to 1373 K, the fracture strength and deformation of TiC-based ceramics were measured at these two critical temperatures. The differences in the behaviors of different TiC sintered bodies and their... 

In the small punch tests (Figs. 11.18 and 11.19), the indentation force versus displacement responses of the punch head were recorded. These punch experiments were performed both at 20°C and at 200°C. Figure 11.20 illustrates representative results from these tests. 

Figure 11.18 Micrograph of a deformed and failed specimen used in a small punch test.

After the DNF model had been calibrated using the uniaxial data, it was validated by simulating the small punch tests. By using the same material parameters that were found in the calibration step (Table... 

Under biaxial drawing conditions of the small punch test (Edidin and Kurtz 2001), the large-deformation mechanical behavior of polyethylene also... 

Representative small punch test data conducted at room temperature at a rate of 0.5 mm/min. 

Edidin A.A., and S.M. Kurtz. 2001. Development and validation of the small punch test for UHMWPE used in total joint replacements. In Functional biomaterials. N. Katsube, W. Soboyejo, and M. Sacks. Eds. Winterthur, Switzerland Trans Tech Publications. 

This chapter reviews the development and application of miniature specimen mechanical testing techniques, based on the small punch test, to the characterization of UHMWPE components for total joint replacement. The development of the small punch test as applied to UHMWPE was motivated by two clinically relevant and related problems the relationship between process and system variables and polymer degradation, and the relationship between mechanical properties and the ensuing wear of the arthroplasty bearing. To a first order approximation, the polymer degradation problem was motivated by mechanical failure of tibial plateau bearings, and the wear problem was motivated by the clinical need to reduce the prevalence of small-particle mediated late-onset osteolysis in total hip arthroplasty systems. 

Four basic metrics are obtained from a load-displacement curve of a material subjected to the small punch test. These include e initial stiffness, peak load, ultimate load, and the maximum displacement at failure. A fifth derived metric, integral work to failure (WTF), is found by integrating the area imder the... 

Chapter 13 Development and Application of the Small Punch Test to UHMWPE... 

Schematic of specimen preparation and small punch test. Typically, cores of net diameter are taken with a custom coring tool set to 0.250 0.001 inches and then sliced into specimens on a lathe. Following facing operations, the final specimens are [19.7-20.0 mils] thick. Specimens are then inserted into a capturing die apparatus through which the hemispherical punch passes. The closed die is mounted to the crosshead of the testing machining and forced over the fixed punch. Dimensions provided here in English units because the test was originally developed in the United States.

Comparison of GUR 1050 in three conditions as described by the respective load-displacement curves. Longevity and DURASUL are commercially available formulations of highly crosslinked UHMWPE, which exhibit the characteristic geometric strain hardening in the drawing phase of the small punch test. Free radical quenching by remelting UHMWPE above its f>eak melt transition typically reduces the observed peak load as exhibited here (Edidin and Kurtz 2001). 

Characteristic features observed on load-displacement curves obtained using the shear punch apparatus. An initial and hardening stiffness in addition to the peak load are the primary metrics used to perform analytical comparisons. Like the conventional small punch test, the shear punch test also may be interpreted qualitatively. (Adapted from Kurtz et al. 2002.)... 

Maximum hysteresis exhibited as a function of ioad for each of the materials tested by Villarraga and colleagues during the development of cyclic small punch test. (Adapted from Villarraga et al. 2002.)... 

ASTM F 2183-02. 2002. Standard test method for small punch testing of ultra-high molecular weight polyethylene used in surgical implants. West Conshohocken, PA American Society for Testing and Materials. 

Kurtz S.M., J.R. Foulds, C.W. Jewett, et al. 1997. Validation of a small punch testing technique to characterize the mechanical behavior of ultra-high molecular weight polyethylene. Biomaterials 18 1659-1663. 

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