This may be achieved by analytical methods, continuum mechanics, finite element analysis (FEA), or direct strain measurement. Researchers focusing on sheet metal forming frequently need to determine the strains in the sheet. Microscale strains from sheet bulge hydroforming experiments for 11, 5, and 1 mm diameter dies are used to show that the strains measured are reasonable and consistent.
With care, the errors were reduced to less than 1% of strain. The maximum variation in the mesoscale and microscale strain measurement static bulge testing was ☒.4% and more typically ☑.3% of true strain. Provided reasonable care is taken, the inherent error in undeformed parts is 0.76% of true strain for samples with 127 µm grids using the strain measurement system described. In addition, a strain grid measurement method using an optical microscope and digital camera is described and an error analysis was performed. The gridding methodology was shown to be accurate with high repeatability. This article evaluates the strain measurement and strains resulting from multiscale sheet metal hydroforming operations for annealed 0.2-mm-thick ASTM 304 stainless steel using a simple method for producing microscale grids that has been previously described. However, microscale strain grid measurement has the advantage over digital image correlation when the researchers wish to avoid polishing and etching the surface of the sheet metal to make the grain structure visible for digital image correlation and where tooling interferes with obtaining images of the workpiece in real time. The cost of these systems is preventing smaller research and development organizations from entering this challenging area or they are sacrificing the ability to determine strains and evaluate material behavior at the microscale.
Larger organizations are utilizing commercially available microscale digital image correlation systems to measure the strains on these scales.
Meso- and microscale sheet metal forming represents new and attractive solutions to many manufacturing problems for product miniaturization. All subjects Allied Health Cardiology & Cardiovascular Medicine Dentistry Emergency Medicine & Critical Care Endocrinology & Metabolism Environmental Science General Medicine Geriatrics Infectious Diseases Medico-legal Neurology Nursing Nutrition Obstetrics & Gynecology Oncology Orthopaedics & Sports Medicine Otolaryngology Palliative Medicine & Chronic Care Pediatrics Pharmacology & Toxicology Psychiatry & Psychology Public Health Pulmonary & Respiratory Medicine Radiology Research Methods & Evaluation Rheumatology Surgery Tropical Medicine Veterinary Medicine Cell Biology Clinical Biochemistry Environmental Science Life Sciences Neuroscience Pharmacology & Toxicology Biomedical Engineering Engineering & Computing Environmental Engineering Materials Science Anthropology & Archaeology Communication & Media Studies Criminology & Criminal Justice Cultural Studies Economics & Development Education Environmental Studies Ethnic Studies Family Studies Gender Studies Geography Gerontology & Aging Group Studies History Information Science Interpersonal Violence Language & Linguistics Law Management & Organization Studies Marketing & Hospitality Music Peace Studies & Conflict Resolution Philosophy Politics & International Relations Psychoanalysis Psychology & Counseling Public Administration Regional Studies Religion Research Methods & Evaluation Science & Society Studies Social Work & Social Policy Sociology Special Education Urban Studies & Planning BROWSE JOURNALS
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