This study proposes a chiral mechanical metamaterial-based energy harvester capable of broadband vibration attenuation and energy harvesting across all polarizations of elastic waves at low frequencies. The design incorporates a complete bandgap and defect structure to achieve simultaneous attenuation and energy harvesting for flexural, longitudinal, and torsional waves. Theoretical eigenfrequency analysis and numerical simulations were used to systematically develop the complete bandgap and defect structure, ensuring compatibility with the overall structure. The proposed chiral mechanical metamaterial with defect (CMMD) demonstrated significant performance improvements, achieving 20.5 times higher electrical output power for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The CMMD's design enables efficient energy harvesting and wave attenuation across all polarizations, making it suitable for applications in energy harvesting and wave attenuation. The study highlights the potential of chiral mechanical metamaterials in various mechanical systems, including structural health monitoring, biomedical devices, and wireless communications. The CMMD's performance was validated through experimental measurements, showing good agreement with numerical predictions. The system's versatility is anticipated to be applicable in various mechanical systems, including structural health monitoring, biomedical devices, and wireless communications. The CMMD's ability to harvest energy from both flexural and longitudinal-torsional waves within the same frequency band, while effectively attenuating all-polarized elastic waves across a broadband range, positions it as a versatile solution for energy harvesting and wave attenuation applications. The study also demonstrates the effectiveness of the CMMD in attenuating and harvesting elastic waves, with the output power being 20.5 times greater for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The results highlight the successful design and implementation of chiral mechanical metamaterials in wave attenuation and energy harvesting applications, spanning various wave polarizations. The versatility of the design approach presented in this study is a key factor in expanding its potential applications, as it can be applied to a wide variety of chiral structures. This adaptability is crucial for the development of innovative solutions across multiple fields. The study also demonstrates the effectiveness of the CMMD in attenuating and harvesting elastic waves, with the output power being 20.5 times greater for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The results highlight the successful design and implementation of chiral mechanical metamaterials in wave attenuation and energy harvesting applications, spanning various wave polarizations. The versatility of the design approach presented in this study is a key factor in expanding its potential applications, as it can be applied to a wide variety of chiral structures. This adaptability is crucial for the development of innovative solutions across multiple fields.This study proposes a chiral mechanical metamaterial-based energy harvester capable of broadband vibration attenuation and energy harvesting across all polarizations of elastic waves at low frequencies. The design incorporates a complete bandgap and defect structure to achieve simultaneous attenuation and energy harvesting for flexural, longitudinal, and torsional waves. Theoretical eigenfrequency analysis and numerical simulations were used to systematically develop the complete bandgap and defect structure, ensuring compatibility with the overall structure. The proposed chiral mechanical metamaterial with defect (CMMD) demonstrated significant performance improvements, achieving 20.5 times higher electrical output power for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The CMMD's design enables efficient energy harvesting and wave attenuation across all polarizations, making it suitable for applications in energy harvesting and wave attenuation. The study highlights the potential of chiral mechanical metamaterials in various mechanical systems, including structural health monitoring, biomedical devices, and wireless communications. The CMMD's performance was validated through experimental measurements, showing good agreement with numerical predictions. The system's versatility is anticipated to be applicable in various mechanical systems, including structural health monitoring, biomedical devices, and wireless communications. The CMMD's ability to harvest energy from both flexural and longitudinal-torsional waves within the same frequency band, while effectively attenuating all-polarized elastic waves across a broadband range, positions it as a versatile solution for energy harvesting and wave attenuation applications. The study also demonstrates the effectiveness of the CMMD in attenuating and harvesting elastic waves, with the output power being 20.5 times greater for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The results highlight the successful design and implementation of chiral mechanical metamaterials in wave attenuation and energy harvesting applications, spanning various wave polarizations. The versatility of the design approach presented in this study is a key factor in expanding its potential applications, as it can be applied to a wide variety of chiral structures. This adaptability is crucial for the development of innovative solutions across multiple fields. The study also demonstrates the effectiveness of the CMMD in attenuating and harvesting elastic waves, with the output power being 20.5 times greater for flexural waves and 511.4 times for longitudinal-torsional waves compared to the defectless chiral mechanical metamaterial. The results highlight the successful design and implementation of chiral mechanical metamaterials in wave attenuation and energy harvesting applications, spanning various wave polarizations. The versatility of the design approach presented in this study is a key factor in expanding its potential applications, as it can be applied to a wide variety of chiral structures. This adaptability is crucial for the development of innovative solutions across multiple fields.