When vibration testing laboratories face large broadband load challenges, maintaining test accuracy while balancing structural rigidity and mass loading becomes a critical engineering dilemma. Unholtz Dickie's (UD) lightweight magnesium alloy head expanders provide a specialized solution designed to address these technical challenges.
Through optimized material properties and geometric structures, this product line demonstrates exceptional performance in enhancing vibration table productivity and expanding testing boundaries.
Core Engineering Advantages
Manufactured from high-performance magnesium alloy, these expanders offer superior strength-to-weight ratios, maintaining structural rigidity while minimizing dead weight. This reduces strain on vibration table armatures and effectively increases system resonant frequencies, ensuring stable output up to 2,000 Hz. Additional key features include:
- High adaptability: Supports multiple geometric configurations (circular, square, rectangular, octagonal) for optimal load distribution based on test specimen shape
- Environmental compatibility: Designed for harsh thermal chamber requirements, easily integrating with various temperature/humidity environmental chambers for coupled mechanical-environmental testing
- Structural stability: Selected models feature guide bearings and additional load support systems for high-performance vibration tables (H560B-16, R16, K170-16, T2000), effectively counteracting overturning moments from large loads
- Economic efficiency: Standardized plug-in mounting hole patterns significantly reduce fixture changeover time, improving laboratory throughput
Technical Specifications and Selection Criteria
Data analysis indicates an inverse relationship between head expander resonant frequency and load size. The following table outlines core parameters of UD's standard series for engineering reference:
| Model | Dimensions (in) | Armature Match (in) | Weight (lb) | Resonant Frequency (Hz) |
|---|---|---|---|---|
| HE12-2424-8 | 24×24×8 | 12 | 110 | 1400 |
| HE16-2424-6.5* | 24×24×6.5 | 16 | 100 | 1500 |
| HE16-2828-6.5* | 28×28×6.5 | 16 | 160 | 1100 |
| HE16-3232-10* | 32×32×10 | 16 | 252 | 1050 |
| HE16-3636-10* | 36×36×10 | 16 | 282 | 900 |
| HE16-4040-12* | 40×40×12 | 16 | 410 | 720 |
| HE16-4444-12* | 44×44×12 | 16 | 440 | 625 |
| HE16-4848-12* | 48×48×12 | 16 | 490 | 530 |
| HE24-3232-7 | 32×32×7 | 24 | 214 | 900 |
| HE24-3636-7 | 36×36×7 | 24 | 241 | 740 |
| HE24-4040-9.5 | 40×40×9.5 | 24 | 360 | 650 |
| HE24-4444-9.5 | 44×44×9.5 | 24 | 405 | 550 |
| HE24-4848-9.5 | 48×48×9.5 | 24 | 452 | 480 |
*Models marked with asterisk support guide bearings and additional load support for heavy load testing scenarios.
Selection Recommendations
Engineers should prioritize test specimen center-of-gravity height and frequency response requirements. For high-frequency testing, thinner, lighter models maintain higher resonant points. For large specimens or high center-of-gravity applications, models with guide bearing support ensure lateral stability and prolong equipment service life. Custom sizing services are available for specialized testing requirements beyond standard specifications.
