U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Material Measurement Laboratory / Materials Science and Engineering Division

Mechanical Performance Group

Projects/Programs

Displaying 1 - 14 of 14

Automotive Lightweighting

Ongoing
The US auto industry spends $600M per year fixing and tweaking forming dies that do not make correct parts. The primary reason that the dies are inaccurate is that the computer models of the dies utilize materials models that are inaccurate. Upon surveying our industrial partners, we determined that
xform

Cruciform Multiaxial Mechanical Testing

Ongoing
A new ARRA funded cruciform test machine is being installed in the NIST Center for Automotive Lightweighting. Its capabilities include 500kN load per axis, two DIC strain mapping systems (one for large field mapping and one for zooming in to study localizations or features), a high resolution, high

Crystal Plasticity Modeling of Yield Surface Evolution

A robust multiaxial constitutive law is needed to predict stresses within parts formed from sheet metal to be able to compensate for such phenomena as elastic springback. Ideally, the constitutive law would not need to be "trained" using empirical mechanical property data alone, but would be able to

Dynamic Plasticity: Non-Equilibrium Mechanics

Ongoing
The optimization of high-speed machining processes through powerful finite element modeling techniques is an important pathway to American manufacturing competitiveness in an increasingly competitive global marketplace. Quantitatively accurate simulations of machining rely on robust constitutive

Fundamentals of Deformation

Ongoing
• We have provided general users from industry, academia and national laboratories with a completely new class of X-ray imaging techniques for materials studies (ultra-small-angle X-ray scattering imaging), that we developed from basic concept to DOE-supported operations at the Advanced Photon
Picture for Hardness and Coating Thickness Standardization and Measurements Project Including Equipment and Standards Organizations

Hardness Standardization and Measurements

Ongoing
DESCRIPTION Purpose: Provide measurement traceability for the Knoop, Rockwell, and Vickers hardness scales and for coating thickness measurements that are based on magnetic methods. Goals: Harmonization of hardness and coating thickness testing protocols, in pursuit of reduction of measurement

High Rate Testing

Ongoing
This project involves sample geometry and metrological development for high rate servohydraulic testing. (Content to be uploaded soon)

Marciniak Multiaxial Testing

Ongoing
This X-ray system can measure the full 3D stress tensor of the sheet in situ under multiaxial tension. The test is performed by raising the punch to stretch the sheet incrementally, then a hold is placed while the stress measurement is made. This step takes 2-4 minutes depending on the accuracy

Physical Infrastructure: Connections

Completed
The NIST Physical Infrastructure Program will provide the critical measurement science needed to assess the condition of aging physical infrastructure and guide cost-effective strategies for its maintenance, repair, and replacement. Infrastructure management challenges in the U.S. have received

Springback

Springback, or the elastic change in shape when a part is released from the manufacturing process, has been a problem for decades and accounts for a significant fraction of the expense that the US auto industry spends each year trying out die sets for new body designs. The inability to predict the

Tension-Compression Testing

Ongoing
The inability to reliably predict the mechanical behavior of new automotive alloys during forming has generated strong demand for more advanced constitutive relationships and property data necessary to calibrate them. There is a particular need for models that incorporate combined kinematic and

Uniaxial Tension Beyond Necking

Ongoing
A major limitation of the uniaxial tensile test (ASTM E8) is that after a certain amount of tensile strain, the sample eventually undergoes a mechanical instability - it forms a neck. Although the sample continues to plastically deform, the stress can no longer be unambiguously determined as load

X-ray Stress Measurement

Ongoing
X-ray diffraction is commonly used to measure a materials crystal structure, crystal lattice orientation, and the spacing of the lattice planes. Our X-ray systems are designed to measure the spacing of one or two specifically selected lattice plane reflections for a given material. The systems use

Yield Surface Measurement

Ongoing
The overarching philosophy for this project is to develop standard tests that produce clean multiaxial yield data for sheet metal that will be of use to the automotive industry in lightweighting efforts. To this end, it is required that the sheet being tested remain in the as-received condition (no