ALLVAR Alloy 30 Design Allowable Properties are here!
From analysis to manufacturing high quality products, engineers need accurate material property data. As a material supplier, ALLVAR understands and has been hard at work collecting reliable material properties for ALLVAR Alloy 30. Now customers that need statistically significant data sets to meet quality requirements can confidently use ALLVAR Alloy 30 in their system designs. The result is ALLVAR Alloy 30’s potential can be unlocked in the most demanding applications where statistically significant design allowable properties are necessary.
What is a design allowable property?
A Material Design Allowable is a statistically significant material property that can be used in a design. Through rigorous testing and statistical analysis of a material and its properties, design allowables give reliable, statistically significant material property data that engineers and designers rely on to meet the performance and quality requirements of demanding applications. These data provide a lower tolerance
There are several types of statistically determined allowable properties known as S-, B- and A-Basis. Each of these can be seen in the corresponding graph. S-basis data assumes the data are normally distributed and uses a minimum of 30 samples. The S-Basis value is then equal to or below 99% of samples with a 95% confidence interval. For applications that require greater statistical rigor, between 100 and 300 samples are required to characterize the type of distribution. In the example, we shows a Weibull distribution for A- and B- There are several types of statistically bases. The B-Basis value is then less conservative where 90% of samples will be equal to or above the B-Basis value with a 95% confidence interval. The A-Basis value is more conservative with 99% of samples being equal to or above the A-Basis value with a 95% confidence interval.
ALLVAR Alloy 30 has taken the next step to be an aerospace-approved material
For determining A- and B-Basis statistical properties, a minimum of 100 tests from 10 heats of materials are needed for each material property. As part of a NASA SBIR Phase II contract, 10 heats of ALLVAR Alloy 30 were manufactured and over 400+ samples cut and tested. These include ultimate tensile strength, tensile yield, compressive yield, elastic modulus, shear modulus, Poisson’s ratio, and shear strength. Each test was performed per the ASTM standards specified by the MMPDS (Metallic Materials Properties Development Standardization) Handbook, formerly known as MIL-HDBK-5. Additionally, compressive and tensile yield and tensile and compressive modulus were tested between -70°C and 100°C. While official S-, B-, and A-basis design allowables can only be determined through Battelle Memorial Institute, these data are valuable to engineers who always wanted to integrate ALLVAR Alloys into their designs, but could not due to material property uncertainty.
More material properties to come: Microyield, Microcreep, and Low Cryogenic CTE Data
When our customers request new data and products, the ALLVAR team listens! We have also tested microyield and microcreep properties for ALLVAR Alloy 30. More to come on that soon. From there, we are working towards CTE data for customers working in the coldest cryogenic environments. Stay tuned for more information!
