# Effect of Loading Rate on Tensile Strength and Fracture Stress of Chocolate

## TL;DR

This study examines how different loading rates affect the tensile strength and fracture stress of various types of chocolate.

## Contribution

The novel contribution is the investigation of chocolate fracture properties under varying loading rates using the Brazilian test and SHPB technique.

## Key findings

- Tensile fracture stress increases with higher loading rates in all chocolate types.
- Fracture sensitivity is lower at low loading rates compared to high loading rates.
- Fracture initiation occurs in the middle of the chocolate specimen.

## Abstract

The fracture properties of five types of chocolate (dark, extra dark, milk, white, and ruby) were investigated using an indirect tensile test known as the Brazilian test. Two different loading rates of 0.0017 m/s and around 12 m/s were used through the universal testing machine TIRATEST and split Hopkinson pressure bar (SHPB) technique. Results show that the tensile fracture stress increases with the loading rate. The sensitivity of the fracture stress at low‐loading rates is lower than that at the high‐loading rates. The obtained results can be used in industry for the correct processing of chocolate products and their transport. The presented methods can be also used to detect defects in chocolate products.

Five different chocolates (extra dark, dark, milk, white, and ruby) were tested using two approaches (low/high‐loading rate) to determine their mechanical behavior. Records of chocolate deformation from a high‐speed camera were presented. Fracture of specimens starts in the middle of the specimen and tensile fracture stress increases with the loading rate.